3D ULTRASOUND IN THE EXAMINATION OF THE FETAL BRAIN

A study of the embryonic and foetal brain is a crucial phase of the ultrasound examination during pregnancy. Application of 3D ultrasound in obstetrics began in 1989 volume acquisition and Multiplanar rendering (so called 3D ultrasound); successively (1991) with the increase in the use of “surface rendering” of the foetal facies.
In one of our studies, the use of 3D ultrasound (3D) on 987 foetuses with physiological brain was of no diagnostic use in examining the foetal brain. In fact, it is not possible to obtain a 3D reconstruction either of an individual encephalic structure or of the brain in toto. On the contrary, Multiplanar ultrasound (so called 3D ultrasound) (Mp rendering (so called 3D ultrasound)) turned out to be the method of choice for an analysis of the foetal brain as it allowed for the following:
· Selection of sagittal and frontal planes, difficult to obtain in free-hand B-Mode;
· Visualisation of brain structures otherwise difficult to study in free-hand B-Mode;
· Multiplanar comparison of individual brain structures on the 3 orthogonal scans by using the stereotaxic voxel (marker dot).

Table 1
Ultrasound scans available for ultrasound signal evaluation in B-Mode vs. V-Mode (Volume-Mode).

Brain Structures Visible in echo B-Mode (2D)
1. Interhemispheric fissure
2. Cavum septi pellucidi (CSP)
3. Third ventricle (3V)
4. Thalami
5. Lateral ventricles: Anterior and posterior horns
6. Cerebellum
7. Cisterna magna
8. Sylvian fissure

More rarely

9. Fourth ventricle
10. Corpus callosum (CC): Percentage of visualisation 5%

Brain Structures Visible in Volume-Mode (Multiplanar ultrasound (so called 3D ultrasound) or Mp rendering (so called 3D ultrasound)):
1. Interhemispheric fissure
2. Cavum septi pellucidi (CSP)
3. Third ventricle (3V)
4. Thalami
5. Lateral ventricles: Anterior and posterior horns
6. Cerebellum
7. Cisterna magna
8. Sylvian fissure
9. Fourth ventricle
10. Corpus callosum (CC): Percentage of visualisation 92%
11. "Architecture" of relation between CC. CSP and 3V
12. Sylvian aqueduct
13. Area of fornix and choroid plexus of the 3rd ventricle
14. Mesencephalon
15. Lamina quadrigemina
16. Cingulate gyrus (GC - cingulate scissure)
17. Brainstem (medulla, pons e mesencephalon)
18. Area of tubercola quadrigemina and epiphysis
19. Early foetal brain structures (Study in progress with Prof. Laurini, University of Lausanne)

EXAMPLES OF BRAIN STRUCTURES VISIBLE IN MP ULTRASOUND: REFORMATTED SAGITTAL AND FRONTAL SCAN

An expert sonographer can ascertain whether a physiologic foetal brain is normal in 30-40 seconds, using a test in B-Mode: In these cases, the multiplanar option may be of little use for a routine brain exam, however, we believe it important for the operator to have knowledge of the morphology of the structures that can be seen on the little familiar sagittal and frontal planes, their spatial architecture and the multiplanar comparison technique in Mp rendering (so called 3D ultrasound), so that he may recognize any alterations undergone by these structures in pathologic conditions (Our group: Multiplanar ultrasound in the examination of physiologic brain. Abstract from the World Congress on Ultrasound Procedures ISUOG 2002 - New York - In Press).

The scientific community should consider and evaluate the need to introduce a second level exam for the pathologic or suspected pathologic brain (Table 2), using Multiplanar ultrasound (so called 3D ultrasound), just as introduced a while ago for the foetal heart (Iaccarino M. Sciaudone G. et al, Ferrara - 2001).

Table II
Illustration of possible use of Multiplanar ultrasound (so called 3D ultrasound) as a tool for second level inquiries in the study of the pathologic or suspected pathologic foetal brain (Our group: Multiplanar ultrasound in the examination of the foetal brain affected by Dandy Walker malformation: New ultrasonographic signs useful for postnatal prognosis – Abstract - Oral Presentation - 12 World Congress on Ultrasound Procedures ISUOG 2002 - New York).

LEGENDS OF FIGURES

Fig. 001a. Illustration of the 3 planes (transversal, frontal and sagittal) used to examine the foetal encephalon.
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Fig. 001a. Illustration of the 3 planes (transversal, frontal and sagittal) used to examine the foetal encephalon. To indicate out how the transversal plane is used routinely in B-mode ultrasound for this study, as is the frontal plane but less frequently. The sagittal plane is scarcely used due to the difficulty that it presents when trying to obtain this scan. Transabdominal volume ultrasound (V-Mode) allows for viewing of 95% in this plane with clear definition compared to 12-15% allowed by classic bidimensional ultrasound (B-Mode).

Fig, 001b
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Fig. 001b. Illustration of various transversal sections of the encephalus available from bidimensional ultrasound.
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Fig, 001b Illustration of various transversal sections of the encephalus available from bidimensional ultrasound.

Fig. 001c
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Fig. 001c. Complete diagram showing transversal and frontal planes used to scan the foetal encephalus in B-Mode.
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Fig, 001c Complete diagram showing transversal and frontal planes used to scan the foetal encephalus in B-Mode. Notice how the transversal scans are not as difficult to obtain routinely in bidimensional ultrasound. 3D ultrasound, however, allows easy viewing of the sagittal plane and, at the same time, compares the three orthogonal scans of any given point of the encephalus by the stereotaxic voxel (marker dot). CF= Frontal horn; CO= Occipital horn; CSP= Cavum septi pellucidi; NT= Thalamic Nucleus; TV= Third ventricle VL= Lateral ventricles.

Fig. 001d
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Fig. 001d. Sagittal foetal section of physiologic foetal brain during 28th week of pregnancy.
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Fig. 001d. Sagittal foetal section of physiologic foetal brain during 28th week of pregnancy. The encephalic structures visible are indicated by arrows. 1 = cingulate gyrus; 2 = corpus callosum; 3 = CSP; 4 = fornix; 5 = choroid plexus of the 3rd ventricle; 6 = 3V; 7 = inter-thalamic adherence; 8 = mesencephalon; 9 = lamina quadrigemina; 10 = epiphysis; 11 = parieto-temporal sulcus; 12 = habenula; 13 = Sylvian aqueduct.

Fig. 001e
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Fig. 1e. Same as preceding case. Structure of the posterior cranial fossa.
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Fig. 1e. Same as preceding case. Structure of the posterior cranial fossa: 1 = mesencephalon; 2 = pons; 3 = medulla; 4 = 4th ventricle; 5 = cerebellum; 6 = lamina quadrigemina.

Fig. 001f
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Fig. 1f. Comparison between physiologic pregnancy on 21st week and post-mortem anatomical findings during same period.
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Fig. 1f. Comparison between physiologic pregnancy on 21st week and post-mortem anatomical findings during same period. Clearly visible are various structures of the posterior cranial fossa difficult to see in B- Mode. 4 = cerebellum; 5 = lamina quadrigemina; 6 = epiphysis; 8 = corpus callosum; 11 = 3V; 12 = 4th ventricle; 13 = Sylvian aqueduct; 14 = habenula; 15 = cisterna magna; 16 = choroid lamina of the 3rd ventricle.

Fig. 002a
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Fig. 2a. Pregnancy at 12th week gestation. 3D ultrasound. Physiologic encephalon: trans-abdominal examination.
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Fig. 2a. Pregnancy at 12th week gestation. Trans-abdominal volume. Multiplanar ultrasound (so called 3D ultrasound). In A (sagittal scan), several encephalic structures are highlighted by markers. To improve image, click on MOVIE. Note that the number of encephalic structures visible during this period by trans-abdominal scan is lower than the number of structures that are visible by trans-vaginal scan (see Fig. 3a and MOVIE 3a). 1 = corpus callosum; 2 = fornix; 3= commissured lamina; 4 = infundibulum; 5 = Sylvian aqueducts; 6 = cerebellum; 7 = lamina quadrigemina; 8 = thalami; 9 = 3rd ventricle.

Fig. 2b. Same as preceding case without markers.

Fig. 2c. Same as preceding case. Note cerebellum biometry of the latero-lateral diameter (10.1mm).

Fig. 3a
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Fig. 3a. Pregnancy at 13th week gestation. 3D ultrasound. Trans-vaginal volume. Multiplanar ultrasound (so called 3D ultrasound). Physiologic foetal brain.
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Fig. 3a. Pregnancy at 13th week gestation. Trans-vaginal volume. Multiplanar ultrasound (so called 3D ultrasound). Physiologic foetal brain. Encephalic structures still developing, have yet to assume their final macroscopic shape.
In A (frontal): 22. meninx + falx cerebri; 23. area sulcus terminalis; 24. choroid plexus; 25. fornix; 26. thalamus; 27. initial hippocampus; 28. sub thalamic area; 29. muscula dorsalis-cervicalis; 30. vertebra; 31. medulla; 32. pons (oblique section); 33. third ventricle.
In B (sagittal): 1. nose and choana; 2. nasal cavities and paranasal sinuses; 3. rhinopharynx 4. oropharynx; 5. oral cavity; 6. tracheal-esophagal area; 7. floor of median cranial fossa; 8. floor of anterior cranial fossa; 9. longitudinal cerebral fissure; 10. CC; 11. thalamus; 12. hypothalamic area; 13. lateral ventricle; 14. habenula; 15. lamina quadrigemina; 16. aqueduct; 17. cerebellum; 18. fourth ventricle; 19. pons; 20. lower olea area; 21. spinal medulla area.

Fig. 3b. Same as preceding case without markers.

Fig. 4a
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Fig. 4a. Pregnancy at 16th week gestation. Multiplanar ultrasound (so called 3D ultrasound). Physiologic foetal brain examined by trans-vaginal volume.
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Fig. 4a. Pregnancy at 16th week gestation. Trans-vaginal volume. Multiplanar ultrasound (so called 3D ultrasound). Foetal brain. In A (sagittal scan), the blue arrows indicate the corpus callosum: At this time it is still in development stage and only the anterior section is completely formed while posterior section is still not visible. The red arrows indicate the area of the fornix and the choroid plexus of the third ventricle, showing acceptable definition. In C, note the cerebellum, measuring 15.40mm. 3V = third ventricle; 4V = fourth ventricle; AS = Sylvian aqueduct; C = Cerebellum; CSP = Cavum septi pellucidi.

Fig. 4b
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Fig.4b. Same as preceding case. The stereotaxic voxel (marker dot) is in the CSP.
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Fig.4b. Same as preceding case. The stereotaxic voxel (marker dot) is in the cavum septi pellucidi, noticeable in the comparison of 3 orthogonal scans. 3V = third ventricle; 4V = fourth ventricle; AS = Sylvian aqueduct; C = Cerebellum; CSP = Cavum septi pellucidi.

Fig. 4c
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Fig. 4c. Same as preceding case. 3D ultrasound. The stereotaxic voxel (marker dot) is positioned in correspondence with the 3rd ventricle.
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Fig. 4c. Same as preceding case. 3D ultrasound. The stereotaxic voxel (marker dot) is positioned in correspondence with the 3rd ventricle, visible in the classic and familiar transversal planes (planes B and C) as well as the sagittal plane. In A, the stereotaxic voxel (marker dot) indicating multiplanar comparison is in effect located in the structure interpreted as the 3rd ventricle; this is confirmed by comparing with the position of the stereotaxic voxel (marker dot) in planes B and C. 3V = third ventricle; 4V = fourth ventricle; AS = Sylvian aqueduct; C = Cerebellum; CSP = Cavum septi pellucidi; T = Thalami.

Fig. 5
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Fig. 5. Pregnancy at 17 weeks, 6 days gestation. Trans-abdominal volume. Multiplanar ultrasound (so called 3D ultrasound). Physiologic brain.
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Fig. 5. Pregnancy at 17 weeks, 6 days gestation. Trans-abdominal volume. Results of Multiplanar ultrasound (so called 3D ultrasound). Physiologic brain. On sagittal plane (A) obtained by computerized reformatting, brain structures are not visible by normal transversal scanning. CSP = CSP; CM = Cisterna Magna; CERV = Cerebellum (vermis); 4V = 4th ventricle; AS = Sylvian aqueduct; 3V = 3rd ventricle (the arrow indicates the caudal area at the entry to the AS); F+P3: Area of the fornix and of the choroid plexus of the 3rd ventricle (at this time the two structures are not distinguishable by TA examination) separating the CSP from the 3V; CC = Corpus callosum; GC = Cingulate gyrus (see Fig. 7). In B (frontal scan at height of 3rd ventricle) the yellow arrows indicate lateral ventricles; green arrows indicate the cingulate gyrus.

Fig. 6
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Fig. 6. 3D ultrasound. Same as preceding case: The stereotaxic voxel (marker dot) is located on the CSP.
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Fig. 6. 3D ultrasound. Same as preceding case: The stereotaxic voxel (marker dot) is located on the CSP, which may be examined simultaneously on 3 orthogonal scans. On plane A (sagittal scan) it is possible to examine the physiologic spatial organisation of the endocranial structures. On plane B (coronal scan), we note the physiologic relation of the CSP with the anterior horns of the ventricles. AHLV = Anterior horns of cerebral ventricles; CSP = Cavum septi pellucidi; CM = Cisterna magna; CERV = Cerebellum (vermis); 4V = 4th ventricle; AS = Sylvian aqueduct; 3V = 3rd ventricle; CC = Corpus callosum; GC = Cingulate gyrus.

Fig. 7
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Fig. 7. Same as preceding case: 3D ultrasound. Magnification of some details.
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Fig. 7. Same as preceding case: 3D ultrasound. Magnification of some details. (A) represents the sagittal plane, (B) the frontal plane, (C) transversal. The stereotaxic voxel (marker dot) point common to the 3 intersected planes is located on the cavum septi pellucidi: The cingulate gyrus, which begins developing during this period, can be seen above the corpus callosum as can most of the pericallous and cingulate sulcus. CC = Corpus callosum; GC = Cingulate gyrus; CSP = Cavum septi pellucidi; AHLV = anterior horns of cerebral ventricles.

Fig. 8
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Fig. 8. Same as preceding case. 3D ultrasound. The stereotaxic voxel (marker dot) (or marker dot) points to the cerebellum
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Fig. 8. Same as preceding case. 3D ultrasound. The stereotaxic voxel (marker dot) (or marker dot) points to the cerebellum which is examined by sagittal (plane A), frontal (plane B) and transversal oblique (plane C) scan. In B, we note that the cerebral vermis completely occupies all the space between the two cerebral lobes, excluding any partial cerebellar agenesis of the cerebellar vermis (see further down) Cereb = cerebellum; Vermis = Cerebellar vermis; CM = Cisterna Magna.

Fig. 9
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Fig. 9. Pregnancy at 28th week gestation. TA Multiplanar rendering (so called 3D ultrasound). Arrows indicate the cerebellar hemispheres and the cerebellar vermis in a physiologic case.
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Fig. 9. Pregnancy at 28th week gestation. TA Multiplanar rendering (so called 3D ultrasound). Foetal brain. On plane A (median sagittal), the red arrow points to the cisterna magna; on planes B and C they indicate, respectively, the posterior coronal plane and transversal plane 1 in which the yellow arrows indicate the cerebellar hemispheres and the red arrow indicates the cerebellar vermis that takes up all the space between the 2 hemispheres, excluding the presence of a partial or total Dandy-Walker syndrome.

Fig. 10
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Fig. 10. Pregnancy at 21st week gestation. Frontal trans-cerebellar scan is used to exclude partial agenesis of the vermis.
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Fig. 10. Pregnancy at 21st week gestation. Trans-abdominal volume. Multiplanar ultrasound (so called 3D ultrasound). Physiologic brain. In A (frontal scan) we note the frontal trans-cerebellar scan used to exclude partial agenesis of the vermis. In B (sagittal scan) encephalic structures are highlighted. These will become visible in the next illustration and by clicking on MOVIE.
1 = epiphysis; 2 = Sylvian aqueduct; 3 = lamina quadrigemina; 4 = cisterna magna; 5 = 4th ventricle; 6 = cerebellum; 7 = medulla; 8 = pons; 9 = mesencephalon (cerebral peduncles); 10 = interthalamic area (3rd ventricle) 11 = fornix; 12 = corpus callosum; 13 cingulate gyrus.

Fig. 11. Same as preceding case without markers.

Fig. 12a
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Fig. 12a Pregnancy at 27th week gestation. Volume-Mode. Multiplanar ultrasound (so called 3D ultrasound). Physiologic foetal brain. The stereotaxic voxel (marker dot) is located in the third ventricle
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Fig. 12a. Pregnancy at 27th week gestation. Volume-Mode. Multiplanar ultrasound (so called 3D ultrasound). Physiologic foetal brain. The stereotaxic voxel (marker dot) is located in the third ventricle, visible simultaneously on the 3 orthogonal scans. In A transversal scan, in B sagittal scan, in C frontal scan.
1 = cingulate gyrus; 2 = corpus callosum; 3 = cavum septi pellucidi; 4 = fornix; 5 = epiphysis; 6 = quadrigeminal tubercles; 7 = cisterna magna; 8 = 4th ventricle; 9 Sylvian aqueduct; 10 = pons; 11 = mesencephalon; 12 = 3rd ventricle; 13 = anterior commissure; 14 = anterior horn of cerebral ventricles; 15 = thalamus; 16 = putamen + globus pallidus; 17 = fornix; 18 = hypothalamus; 19 = external capsule; 20 = extreme capsule; 21 = insula; 22 = claustrum; 23 = corpus nuclei caudati; 24 = interhemispheric septum; 25 = choroid plexus; 26 = posterior ventricular horn; 27 = Sylvian fissure.
This illustration should be compared with the subsequent one in which markers have not been included.
To improve visibility of structures, click on MOVIE.

Fig. 12b. Same case and same image as preceding, without markers.

Fig. 12c
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Fig. 12c. Pregnancy at 27th week gestation. Trans-abdominal volume. Physiologic foetal brain. 3D ultrasound. The stereotaxic voxel (marker dot) is located on the cavum septi pellucidi.
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Fig. 12c. Pregnancy at 27th week gestation. Trans-abdominal volume. Physiologic foetal brain. 3D ultrasound. The stereotaxic voxel (marker dot) is located on the cavum septi pellucidi. In A, the red arrows indicate the corpus callosum, which is sufficiently visible for study. Note that the voxel point for multiplanar comparison is located on the cavum septi pellucidi. In A, the red arrows highlight the corpus callosum while the green arrows indicate the cingulate gyrus that follows the same path as the corpus callosum. On plane B (coronal scan), we note the cingulate gyrus (1), the anterior horns of the cerebral ventricles (2), the temporal horns of the cerebral ventricles and the cavum septi pellucidi (4). On plane C (transversal scan), the same structures are visible: We note the two circumvolutions of the gyrus (arrow 1) in front of the frontal horns of the cerebral ventricles (arrow 2), right and left, following the curve of the cavum septi and, in turn, the corpus callosum. Cerv = cerebellum; 3V = 3rd ventricle.

Fig. 12d
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Fig. 12d. Pregnancy at 23rd week gestation. 3D ultrasound. Foetal brain. Lateral view. Large legend
Fig. 12d. Pregnancy at 23rd week gestation. 3D ultrasound. Foetal brain. Lateral view. The occipital (O), temporal (T), parietal and frontal (F) lobes are visible. 1 = medulla; 2 = pons; 3 = Sylvian fissure; 4 = upper temporal sulcus; 5 = cerebellum. The mesencephalon is not visible.

Fig. 12e
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Fig. 12e. Median sagittal section of the brain, in toto.
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Fig. 12e. Median sagittal section of the brain, in toto. The following brain structures can be seen. 1 = medulla; 2 = pons; 3 = mesencephalon; 4 = area of the ocular nerve and chiasma; 5 = fornix; 6 = Cavum septi pellucidi; 7 = cingulate gyrus; 8 = corpus callosum; 9 = parietal/occipital fissure; 10 = epiphysis; 11 = lamina quadrigemina; 12 = Sylvian aqueduct; 13 = 4th ventricle.

Fig. 12f
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Post-mortem examination of foetal brain at 24th week. Trans-ventricular and trans-thalamic section.
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Fig. 12f. Post-mortem examination of foetal brain at 24th week. Trans-ventricular and trans-thalamic section. The following structures are visible. 1 = area of hyppocampus; 2 = Sylvian fissure; 3 = fornix; 4 = Caudate nucleus; 5 = anterior horn of lateral ventricle; 6 = Cavum septi pellucidi; 7 = interhemispheric fissure; 8 = 3rd ventricle.

Fig. 13
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Fig. 13. Pregnancy at 32nd week gestation. Multiplanar ultrasound (so called 3D ultrasound) of physiologic encephalon. On sagittal scan the corpus callosum is highlighted by the red arrows
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Fig. 13. Pregnancy at 32nd week gestation. TA ultrasound. Multiplanar ultrasound (so called 3D ultrasound). Foetal brain. On plane A, (sagittal scan) the corpus callosum is highlighted by the red arrows, the fornix columns (yellow arrow) that separate the CSP (orange arrow) from the 3rd ventricle (green arrow). The white arrow points to the cerebellum. On plane B (median coronal), we note the 3rd ventricle (red arrow) between the two thalami (T) and, marked by the stereotaxic voxel (marker dot), the posterior section of the CSP (orange arrow) that appears to be circular in the transversal section, the circumvolutions of the gyrus (green arrows) and a transversal section of a supra-marginal cerebral convolution (yellow arrows). On plane C, the 3rd ventricle (red arrow) is visible.

Fig. 14
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Fig. 14. Same as preceding case. 3D ultrasound. The stereotaxic voxel indicates the CSP.
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Fig. 14. Same as preceding case. 3D ultrasound. The comparative voxel indicates the CSP on plane A (sagittal scan). Note the CC (red arrows), CSP (yellow arrow), fornix, 3V (blue arrow). On plane B (coronal), note the CSP (yellow arrow), anterior horns of the lateral ventricles (green arrows), revolutions of the gyrus (red arrows) and the transversal section of a supra-marginal cerebral convolution (blue arrows). On plane C, note the CSP (yellow arrow) and the 3V (blue arrow).

-----PATHOLOGIES OF POSTERIOR CRANIAL FOSSA------

Fig. 15a
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Fig. 15a. Pregnancy at 23rd week gestation. TA ultrasound. Multiplanar ultrasound (so called 3D ultrasound). Complete agenesis of cerebellar vermis (complete Dandy-Walker).
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Fig. 15a. Pregnancy at 23rd week gestation. TA ultrasound. Multiplanar ultrasound (so called 3D ultrasound). Complete agenesis of cerebellar vermis (complete Dandy-Walker). On plane A (coronal) the red arrows indicate the cerebellar lobes. The yellow arrow highlights a minimal residue of the cerebellar vermis, which is missing. The yellow arrow highlights the extended cisterna magna. On plane B (median sagittal) the green arrow highlights the extended cisterna magna, the yellow arrow highlights the remains of the cerebellar vermis identified by multiplanar comparison, blue arrows 1 and 3 highlight, respectively, the CSP and the 3V, separated by the fornix columns (arrow 2). In C we note the classic transversal oblique plane with cerebellar lobes (red arrows), including the reduced remnants of the cerebellar vermis.

Fig. 15b
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Fig. 15b. Pregnancy at 20th week gestation. Multiplanar ultrasound (so called 3D ultrasound). Foetus affected by serious cystic hygroma associated with complete Dandy-Walker.
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Fig. 15b. Pregnancy at 20th week gestation. Trans-abdominal volume examined by Multiplanar ultrasound (so called 3D ultrasound). Foetus affected by serious cystic hygroma and complete agenesis of cerebellar vermis with hypoplasia of cerebellar lobes (compatible with complete DW). In A, note compression of brainstem to the floor of the clivus.

Fig. 16a
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Fig. 16a. Pregnancy at 18th week gestation. 3D ultrasound. Foetus affected by Dandy Walker variant.
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Fig. 16a. Pregnancy at 18th week gestation. 3D ultrasound. Foetus affected by Dandy Walker variant. Stereotaxic voxel (marker dot) is located on the residual area of the vermis. Note clarity of sagittal scan highlighting graphic signs not easily visible in B-Mode. 1 = residual vermis; 2 = area in which no vermis is present (4th ventricle dilated); 3 = medulla; 4 = pons; 5 = mesencephalon; 6 = 3rd ventricle; 7 = fornix; 8 = corpus callosum; 9 = CSP.

Fig. 16b
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Fig. 16b. Same as preceding case and same volume. 3D ultrasound. The stereotaxic voxel (marker dot) now points to 4th dilated ventricle.
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Fig. 16b. Same as preceding case and same volume. 3D ultrasound. The stereotaxic voxel (marker dot) now points to 4th dilated ventricle (or minus vermis area), which can be viewed simultaneously on the 3 orthogonal scans.

Fig. 17a
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Fig. 17a. Pregnancy at 23rd week gestation. 3D ultrasound. Arachnoid cyst of posterior cranial fossa. Confirmed at birth.
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Fig. 17a. Pregnancy at 23rd week gestation. Multiplanar ultrasound (so called 3D ultrasound). Sub cerebellar dilatation: Results compatible with arachnoid cyst of posterior cranial fossa. Confirmed at birth.

Fig. 17b
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Fig. 17b. Pregnancy at 33rd week gestation. Multiplanar ultrasound (so called 3D ultrasound). Arachnoid cyst in posterior cranial fossa.
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Fig. 17b. Pregnancy at 33rd week gestation. Multiplanar ultrasound (so called 3D ultrasound). Arachnoid cyst in posterior cranial fossa. The stereotaxic voxel (marker dot) is located in the 3rd ventricle.
1 = corpus callosum; 2 = CSP; 3 = fornix; 4 = choroid plexus of the 3rd ventricle; 5 = epiphysis; 6 = lamina quadrigemina; 7 = cerebellum; 8 = extended 4V; 9 = extended Sylvian aqueduct; 10 = 3V; 11 = thalami; 12 = cerebellar lobes; 13 = cerebellar vermis; 14 = arachnoid cyst of posterior cranial fossa.

Fig. 17c. Same case and same image as preceding illustration, without markers.

Fig. 17d
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Fig. 17d. 3D ultrasound. Same as preceding case with stereotaxic voxel (marker dot) on enlarged 3rd ventricle.
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Fig. 17d. 3D ultrasound. Same as preceding case with stereotaxic voxel (marker dot) on enlarged 3rd ventricle. Arachnoid cyst in posterior cranial fossa. See captions Fig. 17b.

Fig. 17e. 3D ultrasound. Same case and same image as preceding illustration, without markers.

Fig. 18a
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Fig. 18a. Pregnancy at 23rd week gestation. TA ultrasound. 3D ultrasound. Cerebellar infarction.
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Fig. 18a. Pregnancy at 23rd week gestation. TA ultrasound. 3D ultrasound. Cerebellar infarction. The yellow arrow indicates acute cerebellar infarction on 3 scans (hyper-echoic cerebellum).

Fig. 18b
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Fig. 18b. Same as preceding case. 3D ultrasound. In A, note the CC (red arrows), the CSP (green arrow) and hypo-echoic area, located underneath the CSP, at height of 3rd ventricle
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Fig. 18b. Same as preceding case. 3D ultrasound. In A, note the CC (red arrows), the CSP (green arrow) and hypo-echoic area, located underneath the CSP, at height of 3rd ventricle (blue arrow – marked by stereotaxic voxel (marker dot) which appears to be dilated compared with transversal section. Area of infarction appears to involve the mesencephalon and thalami which appear insufficiently evident upon comparison of planes A and C. The CC, CSP and 3V appear to prolapse toward the bottom.

Fig. 19a
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Fig. 19a. Pregnancy at 21st week gestation. Foetus affected by Chiari II examined by Multiplanar ultrasound (so called 3D ultrasound): Massive cerebral prolapse.
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Fig. 19a. Pregnancy at 21st week gestation. Foetus affected by Chiari II: Massive cerebral prolapse. In transversal section (C) no sign of banana due to intense prolapse; on plane A however (sagittal plane), one can see the prolapsed cerebellum resting on the rachis. 1 = corpus callosum shifted downward; 2 = CSP; 3 = mesencephalic area; 4 = prolapsed cerebellum resting on rachis; 5 = 4V; 6 = rachis; 7 = pontine area resting on rachis.

Fig. 19b
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Fig. 19b. Post-mortem examination of pregnancy at 21 week gestation. Foetus affected by malformation, type Chiari II.
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Fig. 19b. Post-mortem examination of pregnancy at 21 week gestation. Foetus affected by malformation, type Chiari II. Posterior opening of calvarial vault and coronal removal of posterior occipito-rachial section, highlighting posterior cranial fossa. O = occipital area; P = parietal area; T = temporal area; 1 = pathologic encephalic stem; 2 = dorsal muscles, sub cutis and cervico-occipital cutis; 3 = exposed rachis.

Fig. 19c
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Fig. 19c. Same as preceding case upon completion of rachis and cranial removal.
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Fig. 19c. Same as preceding case upon completion of rachis and cranial removal. Rear view of foetal brain highlighting encephalic structures of posterior cranial fossa: The cerebellum appears to protrude toward the bottom due to the cerebral prolapse. O = occipital area; 1 = cerebellum; 2 = brain stem; 3 = spinal chord.

Fig. 19d
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Fig. 19d. Foetal brain at 21st week of pregnancy affected by Chiari II malformation. Lateral view highlights prolapse of cerebellum toward the rachis.
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Fig. 19d. Foetal brain at 21st week of pregnancy affected by malformation type Chiari II. Lateral view highlights prolapse toward the rachis of cerebellum (5), brain stem (2, 3, 4) and spinal chord, secondary to rachischisis (spina bifida) and consequent myelomeningocele.
Occipital(O), temporal (T), parietal and frontal (F) lobe. 1 = spinal chord; 2 = medulla; 3 = cerebellum. Mesencephalon and pons not visible.

Fig. 19e
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Fig. 19e. Post-mortem examination of normal brain at 21st week of pregnancy for comparison with following illustration of pathologic foetus affected by Chiari II
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Fig. 19e. Post-mortem examination of normal brain at 21st week of pregnancy for comparison with following illustration of pathologic foetus affected by Chiari II. Note normal endocranial structures in coronal section. T = thalami; 1 = cerebral ventricular horns; 2 = 3rd ventricle (interthalamic area); 3 = mesencephalic area; 4 = pons; 5 = medulla.

Fig. 19f
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Fig. 19f. Post-mortem examination of foetus affected by Chiari II: coronal section.
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Fig. 19f. Post-mortem examination of foetus affected by Chiari II: coronal section. Note pathologic dilation of cerebral ventricles caused by cerebellar prolapse and consequent compression of flow of spinal fluid. T = thalami; 1 = ventricular horns; 2 = 3rd ventricle.

---------PATHOLOGIES OF MEDIAL CRANIAL FOSSA -------

Fig. 20a
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Fig. 20a. Pregnancy at 23rd week. Multiplanar ultrasound (so called 3D ultrasound). Agenesis of corpus callosum. The stereotaxic voxel (marker dot) is located in the third ventricle.
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Fig. 20a. Pregnancy at 23rd week. Multiplanar ultrasound (so called 3D ultrasound). Agenesis of corpus callosum. The stereotaxic voxel (marker dot) is located in the third ventricle, shifting upward. A, sagittal scan, B frontal scan, C transversal scan. In C, the arrow indicates absence of the cavum septi pellucidi at height of third anterior of the median line. On left, note image visible in A: The broken green line, indicated by the green arrow, denotes absence of fornix between the remaining space corresponding to the cavum septi pellucidi (1) and the space corresponding to the third ventricle shifted upward (2); also visible is the Sylvian aqueduct (3) and the 4th ventricle located in front of the third median of the cerebellum (5). Note absence of the cavum septi pellucidi with respect to the figure on the right. Image on the right displays encephalic structures of a physiologic foetal brain: Visible are the corpus callosum (CC), the Cavum septi pellucidi (1) the fornix (green and indicated by a green arrow), the third ventricle (2), the Sylvian aqueduct (3) the 4th ventricle (4) and the cerebellum (5). The fornix separates the cavum septi pellucidi from the third ventricle. T = Thalami.

Fig. 20b
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Fig. 20b. Pregnancy at 23rd week gestation. Multiplanar ultrasound (so called 3D ultrasound). Agenesis of corpus callosum. The stereotaxic voxel (marker dot) is located in the fourth ventricle
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Fig. 20b. Pregnancy at 23rd week gestation. Multiplanar ultrasound (so called 3D ultrasound). Agenesis of corpus callosum. The stereotaxic voxel (marker dot) is located in the fourth ventricle in front of the third superior of the cerebellum. A, sagittal scan, B frontal scan, C, transversal scan (the yellow arrow indicates the 4th ventricle, marked by the multiplanar comparison voxel). The image reproduces the image visible in A: Note the cavum septi pellucidi (1), the space corresponding to the third ventricle shifted upward (2); also visible are the Sylvian aqueduct (3) and the 4th ventricle in front of the third median of the cerebellum (5). Note absence of Cavum septi pellucidi.

Fig. 20c
Legend for icons:
Fig. 20c. Same case as in previous figure and same volume. Multiplanar ultrasound (so called 3D ultrasound). Agenesis of the corpus callosum.
Large legend
Fig. 20c. Same case as in previous figure and same volume. Multiplanar ultrasound (so called 3D ultrasound). Agenesis of the corpus callosum. A, sagittal scan, B, frontal scan, C, transversal scan. In A, the broken green line indicates the selection level of transversal plane in C to view sign of the ‘drop’. In C, the anterior horn is measured and is found to be narrower with respect to the posterior horn. In B, both anterior horns are measured and sizes may be superimposed.

Fig. 20d. Same as preceding case. Measurement of posterior horn. Size greater than anterior horn.

Fig. 21
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Fig. 21. Pregnancy at 28th week gestation. TA ultrasound. Multiplanar rendering (so called 3D ultrasound). Cyst of cavum septi pellucidi.
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Fig. 21. Pregnancy at 28th week gestation. TA ultrasound. Multiplanar rendering (so called 3D ultrasound). Cyst of cavum septi pellucidi. Patient arrived for observation with suspected partial agenesis of the corpus callosum because of the irregular shape in transversal scan. On plane A (median sagittal) note non original scan obtained by computerised reformatting visualising the corpus callosum (CC= red arrow), CSP (yellow arrow) and 3V (blue arrow). The green arrow points to the fornix columns that separate the CSP from the 3rd ventricle. On plane B (coronal), we note CSP is extended and irregular (yellow arrow). Along sides note AHLV proximal right to probe (red arrow). C displays the transversal scan in which the yellow arrow highlights the extended cavum septi pellucidi.

---------HYDROCEPHALUS---------------

Fig. 22
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Fig. 22. Pregnancy at 20th week gestation. Trans-abdominal volume. Hydrocephalus examined by Multiplanar rendering (so called 3D ultrasound) on sagiptal scan.
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Fig. 22. Pregnancy at 20th week gestation. Trans-abdominal volume. Hydrocephalus examined by Multiplanar rendering (so called 3D ultrasound) on sagiptal scan. Note in A (sagittal scan) dilation of 3rd ventricle, AS and 4V.
1 = 4V; 2 = AS; 3 = 3V; 4 = cerebellum; 5 = lamina quadrigemina distorted by compression of enlarged Sylvian aqueduct; 6 = CSP compressed between the two ventricular horns.

Fig. 23a
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Fig. 23a. Pregnancy at 25th week gestation. Trans-abdominal volume. Multiplanar rendering (so called 3D ultrasound). Hydrocephalus. The stereotaxic voxel (marker dot) is placed in 3rd ventricle.
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Fig. 23a. Pregnancy at 25th week gestation. Trans-abdominal volume. Multiplanar rendering (so called 3D ultrasound). Hydrocephalus. The stereotaxic voxel (marker dot) is placed in 3rd ventricle. A (sagittal scan) highlights encephalic structures rarely visible by free-hand B-Mode. To improve view of structures, click on MOVIE of this illustration and the subsequent one without markers. B: Frontal scan; C (transversal scan), measurement of posterior horn ( = 16mm).
CC = corpus callosum; 1 = CSP; 2 = fornix; 3 = 3 ventricle; 4 = mesencephalon, pons and medulla; 5 = 4th ventricle; 6 = cerebellum; 7 = Sylvian aqueduct; 8 = cisterna magna; 9 = lamina quadrigemina; 10 = epiphysis.

Fig. 23b. The preceding illustration repeated here without markers.

Fig. 23c. Same as preceding case, same volume differently reformatted. Stereotaxic voxel (marker dot) positioned in CSP. 1 = CSP.

Fig. 24a
Legend for icons:
Fig. 24a. Pregnancy at 25th week gestation. Trans-abdominal volume. Multiplanar ultrasound (so called 3D ultrasound). Hydrocephalus.
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Fig. 24a. Pregnancy at 25th week gestation. Trans-abdominal volume. Multiplanar ultrasound (so called 3D ultrasound). Hydrocephalus.
The fetus (who was not screened for foetal malformations during the second trimester) was suspected for agenesis of the corpus callosum because of lack of CSP visualisation. The stereotaxic voxel (marker dot) is positioned in the 3rd dilated ventricle.
A (sagittal scan) highlights corpus callosum (1- red arrow), the CSP (2) (this latter does not clearly appear in this plane because of the compression between the anterior horns), the fornix (3 - green arrow) separating the CSP from the enlarged third ventricle (4): 3V appears as a hypo-echoic area rather than typically echoic because of the hydrocephalus. The margins are unclear due to the physiological inter-thalamic adherence. B (sagittal scan) displays third ventricle as dilated (4). See following illustration.

Fig. 24b
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Fig. 24b. Same as preceding case and same volume differently reformatted. 3D ultrasound. The stereotaxic voxel (marker dot) is positioned in the CSP.
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Fig. 24b. Same as preceding case. Same volume. 3D ultrasound.The stereotaxic voxel (marker dot) is positioned in the CSP: Comparison of A and C put in evidence the CSP (2) compressed between the two anterior horns. In A, the 3rd ventricle appears to be dilated but normally positioned respect of the CSP. CSP and 3V are separed by the fornix (green arrow - 3).

EXPERT ZONE – HEART

MULTIPLANAR AND 3D ULTRASOUND IN THE STUDY OF THE FETAL HEART:
Our experience.
Zosmer, Campbell et al have demonstrated, under favorable conditions, the validity of volumetric data in the examination of some heart scans. These authors were able to obtain data on the apical and lateral volumes of the fetal heart of 54 patients, and have subsequently re-examined the images produced. These patients’ gestational ages were between 17 and 37 weeks; the most suitable scans were chosen for diagnosis. The main scans sought were the following:
• 4 chambers;
• Left long-axis ;
• Aortic crest;
• Short-axis;
• Ductal arch;
Surprisingly, the movements of the cardiac muscle and valve cause slight distortion and thus provide little indication on the quality of the ultrasonographic volume and the plane scans of the apical volumes. On the other hand the quality of the lateral cardiac volumes obtained is compromised by the cardiac movements. The most suitable period for a multiplanar (MP) echocardiographic examination seems to be between the 22nd and 27th gestation week. Volumetric Multiplanar ultrasound (so called 3D ultrasound) allows the reproduction of an ultrasound image of the fetal corporeal volume which can be easily examined with tomographic images, allowing the simultaneous comparison of the voxel point on multiplanar scans. These are particularly useful for structured anatomy examinations of regions with a defined spatial organization and measuring more than 2 or 3 mm (the limit being the ultrasound resolution) like fetal brain and heart. The use of these instruments is of great advantage when studying the heart, provided that the volume is significant. The possibility to compare one point on two or three orthogonal scans allows a more accurate examination of the cardiac connection, and more significant images, from a medic-legal point of view, than the B-Mode examination.
The advantages of a fetal echocardiacography using volumetric examination can be summarized as follows:
1. The possibility to examine and compare the position of the same point (voxel point) on 3 orthogonal planes. This is particularly useful to study fetal cardiac connections and to produce more exhaustive and precise comparative images that are more useful for medical legal purposes;
2. Volumes may be stored on 2 Gb Jaz discs, or on IBM-compatible PC by transferring the volume by a DICOM system, so as to carry out the examination at the end of the pregnancy or even later, if necessary;
3. Reduced examination time;
4. The data on the cardiac volume may be submitted to a more experienced examiner or to other centres (by storing the data on Syquest/Jaz removable disk or transmitting the data stored on the PC via telephone connection);
5. The data on fetal cardiac volume at a given gestational age may be stored for future retrieval. As a matter of fact, since some prenatal fetal heart pathologies can evolve, it may be useful to be able to evaluate a posteriori prenatal conditions for any possible medico-legal controversies;
6. Acquisition of material for didactic purposes (training of operators who specialise in fetal echocardiography.
OUR STUDIES OF THE FETAL HEART:
Our experience with 125 pregnancies confirms and partly expands Zosmer’s results. The scans we obtained and examined (see below) by a single volume are as follows:
• 4 chambers;
• Long left axis with voxel point, for multiplanar comparison, on the corresponding oblique short axis;
• Crossing of the long right axis with voxel point, for multiplanar comparison, on the corresponding oblique short axis;
• Crossing with the long right axis
• Right short axis;
• Ventricular short axis;
• Aortic arch with neck vessel;
• Pulmonary arch continuing into the ductus arteriosus;
• Pulmonary veins in the left atrium: The use of reformatted scans allow us to visualise a coronal section of the 4 pulmonary veins in the left atrium, and to compare the position of the voxel point on the corresponding transverse scan of the 4 chambers;
• Superior and inferior vena cava in right atrium, allowing us to compare the voxel point on the corresponding transverse scan of the 4 chambers.
The undergoing study still requires a statistical validation; nevertheless, its provisional results show that in 72% of cases it enabled a complete or nearly complete morpho-volumetric cardiac examination of fetal heart based on a single volume acquisition.
When the ultrasonographic volume is significant, it is possible to perform an exhaustive morpho-volumetric ultrasonography that traces the phases of a B-Mode Real-Time examination:
• Examination of the veno-atrial connection;
• Examination of the ventricular arterial connection;
• Examination of the atrio-ventricular connection and the atrio-ventricular valves.
The diagnostic value of the images of the cuspid valves, obtained with the volume examination, is still debated. As a matter of fact, Zosmer underlines that during a rapid volumetric acquisition (approx. 3 seconds) about 4 to 5 cardiac cycles may occur, which can invalidate the quality of the valvular images obtained. Actually, considering that the minimum time for a volumetric image corresponds to 3 seconds (about 4 to 5 cardiac cycles), the time needed to obtain the images of the single valve corresponds to less than 0.20 seconds, which is equal to less than half one cardiac cycle. Therefore the image of the valve can be influenced by negligible artifacts.
Actually pseudo-quadrimensional ultrasound has recently been introduced in commercially available V-Mode machines (see MOVIE below): unfortunately the acquisition system of multiple scans, in every single “slide” of the acquired volume, are not synchronized with fetal cardiac cycle: therefore the movies presents artifacts and are not actually useful neither for fetal multiplanar echocardiography nor for live 3D ultrasound of cardiac structures physiologically in movement, while in post-natal life, the synchronization of the acquired images with the cardiac cycle allows a good 3D ultrasound of post-natal heart.

In any case the evaluation of valvular movements through MP ultrasound (so called 3D ultrasound)is not actually advisable. The evaluation of the veno-atrial and ventricular-arterial connections can, however, in some conditions, take advantage of a volumetric examination of the fetal heart.
In our recent study we have examined the pulmonary veins connections to left atrium: it was possible to document the 4 pulmonary veins in LA in 46% of cases (Varvarigos E, Iaccarino M et al.: Multiplanar ultrasound (so called 3D ultrasound) in the identification of four pulmonary veins in left atrium. Abstract - ISUOG World Congress. New York, 2002).
The current limitations of the volumetric examination in fetal echocardiography consist of the acquisition mechanism: It is therefore necessary to perform a 'real-time volume' assessment at the end of the study, or to use any other method that allows the acquisition of a single volume in less than 0.1 second and to obtain a sequence of volumetric frames at the end of a study of the cardiac valves on both multiplanar volumetric examination and in 3D.
WHAT ARE WE EVALUATING?
Our team is studying cardiac ventricular ejection: The pulsatory ejection is the product of TPI (the integral of the Doppler spectrum curve) multiplied by the area defined by the aortic valve and pulmonary annulus, resulting by the reformatted plane sections showing the valvular circumference. The measurement of the resulting area is a reliable datum as it is taken from the measurement of the diameter or radius, which are calculated by regression to the circumference and not by direct measurement. In addition, we are devising a method to measure the residual cardiac volume (calculated from the segmentation of the cardiac chamber taken on 3 scans) and the holosystolic volume ejected from the heart (calculated as reported above).

LEGENDS OF FIGURES

Fig. 001
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Fig. 001. Schematic illustration of the acquisition of valvular sub-volume, based on a 4-chamber view.
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Fig. 001. Schematic illustration of the acquisition of valvular sub-volume, based on a 4-chamber view. In the center are the original unformatted scans. T1 and T2 are the acquisition of the ventricular proto and tele-diastole. T3 shows the ventricular systole. T4 and T5 illustrate a new cycle of ventricular proto and tele-diastole. The computerized translation of the original unformatted scans provides a sequence of images that enable the study of the valvular kinetics of the fetal heart.

Fig. 002
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Fig. 002. The scheme describes Multiplanar ultrasound (so called 3D ultrasound) applied to fetal heart examination.
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Fig. 002. The scheme describes Multiplanar ultrasound (so called 3D ultrasound) applied to fetal heart examination. The original unformatted scan (perspective 1) is composed of planes P1, P2, ...PN, the voxel points of which are simultaneously acquired at times T1, T2, ...TN. The two orthogonal scans, non original but reformatted (perspectives 2 and 3), are composed, on the contrary, of points acquired at different times T1, T2, ...TN, and therefore cannot be utilized for valve movement examination nor for any other dynamic structure evaluation.

Fig. 003
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Fig. 003. Pregnancy at 21st week gestation. Multiplanar rendering (so called 3D ultrasound). Four chamber view and inter-ventricular septum are visualised.
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Fig. 003. Pregnancy at 21st week gestation. Trans-abdominal examination. Multiplanar rendering (so called 3D ultrasound). In A (transversal scan) the four chamber view is visualised. The red arrows show the inter-ventricular septum. LA = left atrium; RA = right atrium; IVS= inter-ventricular septum; T= tricuspid.

Fig. 004
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Fig. 004. Comparison between left long axis view and right short axis by Multiplanar ultrasound (so called 3D ultrasound) and stereotaxic voxel.
Large legend:
Fig. 004. Same case and same volume as in previous figure. Scan A is selected and left long axis view is obtained by computerised, non original, reformatted translation. Notice the integrity of the IVS outlet septum. Stereotaxic voxel (red arrow in A and B), which is the point of intersection of the 3 orthogonal scans, allows the comparison and identification of the aorta on scan A (left long axis) with the same point of the aorta visualised on scan B (slightly oblique right short axis). The yellow arrow in A represents the direction of the aorta on scan A compared to the pulmonary artery (PA) of Fig. 5 (Scan A).
Ao = aorta; Polm= pulmonary artery; LV= left ventricle; Rv= right ventricle; Sp= rachis.

Fig. 005
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Fig. 005 Comparison between right long axis view and right short axis by Multiplanar ultrasound (so called 3D ultrasound) and stereotaxic voxel.
Large legend:
Fig. 005. Same case and same volume as in previous figure. Scan A is translated upwards: pulmonary artery continues in the ductus arteriosus. To point out how the pulmonary artery crosses the aorta of previous figure (scan A). The yellow arrow shows the direction of the aorta as indicated in plane A of Fig. 4 while the red arrow shows the direction of the pulmonary artery: it infers the physiological crossing over between 2 vessels. Notice the different position of the stereotactic voxel (red arrow) on scan B (pulmonary arch scan) from the aorta (Fig. 4 – scan B - Ao) to the pulmonary artery near the DA (present figure: scan B - Polm). Ao= aorta; Polm = pulmonary artery; Rv= right ventricle: Sp= rachis.

Fig. 006
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Fig. 006. 3D ultrasound. The stereotaxic voxel marks the pulmonary artery both on right long axis (scan A) and on the right short axis scan (scan B). Large legend:
Fig. 006. Same case and same volume as in previous figure. 3D ultrasound. Scan B is mildly rotated in order to obtain a right short axis scan from the previous pulmonary arch scan (scan B of previous figure). The stereotaxic voxel marks the pulmonary artery both on right long axis (scan A) and on the right short axis scan (scan B).
On scan A: arrow 1= pulmonary artery – stereotaxic voxel; arrow 2 = ductus arteriosus continuing to the descending aorta; arrow 3= right pulmonary artery. On scan B: arrow 1= DA; arrow 2= PA; arrow 3= RV; arrow 4 = aorta.

Fig. 007
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Fig. 007. 3D ultrasound. The volume is rotated in order to obtain a ventricular short axis on scan C
Large legend:
Fig. 007. Same case and same volume as in previous figure. 3D ultrasound. The volume is rotated in order to obtain a ventricular short axis on scan C: this scan is compared with scan A (4 chambers view). On scan A the yellow line put in evidence the level of the scan visualised on scan C. On scan C the typical circular form of the left ventricle and the 'bellows' form of the right ventricle are visualised. This multiplanar image, which make possible the comparison of different orthogonal scans of a same point (voxel), is unobtainable in B-Mode and is an original MP-image: that is very important for forensic purposes.
LV= left ventricle; RV= right ventricle; Sp= rachis.

Fig. 008a
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3D ultrasound. The volume is rotated in order to obtain a ventricular short axis on scan C
Large legend:
Fig 8a Same case and same volume as in previous figure. 3D ultrasound. Situs solitus (first scan). Comparison between the transversal scan (4 chamber - scan A) and longitudinal scan (pulmonary arch scan - scan B). Notice in B how the stereotaxic voxel is placed at the height of the heart.
Ao= Aorta; AS= left atrium; Sp= rachis in transverse section; VD= right ventricle; 1= right ventricle; 2= pulmonary artery; 3= DA; 4= descendant aorta; 5= aorta.

Fig. 008b
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Fig. 008b Situs solitus. 3D ultrasound. Comparison between the transversal scan of the abdomen and the longitudinal scan of the 'pulmonary arc'
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Fig. 008b Same case and same volume as in previous figure. Situs solitus. Comparison between the transversal scan of the abdomen (plane A) and the longitudinal scan of the 'pulmonary arc'(plane B). Notice in B that the stereotaxic voxel is positioned under the diaphragm. Ao= aorta; St= stomach; IVC= inferior vena cava ; 1= RV; 2= pulmonary artery; 3= DA; 4= descending aorta; 5= aorta.

Fig. 009
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Fig. 009 3D ultrasound. Longitudinal scan of the aortic arc is compared with transversal '4 chambers' scan.
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Fig. 009 Same case and same volume, differently reformatted, as in previous figure. 3D ultrasound. Longitudinal scan of the aortic arc (plane A) is compared with transversal '4 chambers' scan (plane B). The stereotaxic voxel (red arrow in A and B) marks the descending aorta. In B it’s possible to visualise the aortic arc in all its length and the 3 vessels of the neck. 1= innominate artery; 2= left carotid; 3= left subclavian artery. IVS = inter-ventricular septum; LV= left ventricle; RV= right ventricle; T= tricuspid valve.

Fig. 010a
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Fig. 010a 3D ultrasound. Comparison between the transversal '4 chamber' scan and the longitudinal scan of the 'pulmonary arc'
Large legend:
Fig. 010a Same case as previous figure. 3D ultrasound. Comparison between the tranverse '4 chamber' scan (plane A) and the longitudinal scan of the 'pulmonary arc' (plane B). In B the stereotaxic voxel (marker dot) is positioned above the diaphragm at the height of the heart. LA= left ventricle; RV= right ventricle; T= tricuspid; red arrows - IVS= inter-ventricular septum.

Fig. 010b
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Fig. 010a 3D ultrasound. Comparison between the transversal '4 chamber' scan and the longitudinal scan of the 'pulmonary arc'
Large legend:
Fig. 10b Same case as previous figure. 3D ultrasound. Transverse right 'long axis' scan (plane A) and longitudinal 'pulmonary arc' scan are compared (plane B). In B the stereotaxic voxel is positioned on the pulmonary artery which continues in the ductus arteriosus (DA). 1= pulmonary artery; 2= DA; 3= right branch pulmonary artery; 4= tract of DA which continues in the descending aorta.

Fig. 011
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Fig. 011 3D ultrasound. Comparison between the transversal '4 chamber' scan and the longitudinal scan of the 'pulmonary arc'
Large legend:
Fig. 011 Same case as previous figure. 3D ultrasound. Longitudinal scan of the inferior/superior vena cava in RA. Comparison of the transverse “4 chamber scan” (plane A) and the longitudinal scan of the inferior/superior vena cava (plane B). Notice in A and B how the stereotaxic voxel (marker dot) is positioned into the right atrium. For this reason the hypo-echogenic area detectable in (B) corresponds to the right atrium in (A). This multiplanar comparative image is exhaustive for the evaluation and documentation of correct systemic venous return in the right atrium and is obtainable only by B-Mode. AD= right atrium; AS; left atrium; Ao= aorta; IVC= inferior vena cava; Sp= rachis; T= tricuspid; VD= right ventricle; VS= left ventricle.

Fig. 012a
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Fig. 012a Pregnancy at 22nd week gestation, examined by Multiplanar ultrasound (so called 3D ultrasound). Visualisation of the inferior left pulmonary vein in left atrium.
Large legend:
Fig. 012a Pregnancy at 22nd week gestation, examined by Multiplanar ultrasound (so called 3D ultrasound). Evaluation of the four pulmonary veins in left atrium. In A (transverse scan), corresponding to the 4 chambers, the left atrium (La) and left ventricle (Lv) can be partially seen. In C (frontal scan) the 4 pulmonary veins can be seen by a non original reformatted coronal scan; this scan is not obtainable in B-Mode ultrasound. Notice how the stereotaxic voxel (marker dot) is positioned on the inferior left pulmonary vein: this latter is thus examinable by comparison on plane A (transverse) and C (frontal). 1= superior left pulmonary vein; 2= superior right pulmonary vein; 3= inferior right pulmonary vein; 4= inferior left pulmonary vein.

Fig. 012b
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Fig. 012b Pregnancy at 22nd week gestation, examined by Multiplanar ultrasound (so called 3D ultrasound). Visualisation of the inferior right pulmonary vein in left atrium.
Large legend:
Fig. 12b Same case as previous figure. The marker dot is positioned on the supposed inferior right pulmonary vein (IRPV): the comparison of C with the familiar transversal scan (plane A) by stereotaxic voxel, confirms the identification of the structure marked in C by the stereotaxic voxel as the IRPV visualised in A.
1= superior left pulmonary vein; 2= superior right pulmonary vein; 3= inferior right pulmonary vein; 4= inferior left pulmonary vein.

Fig. 012c
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Fig. 012c Pregnancy at 22nd week gestation, examined by Multiplanar ultrasound (so called 3D ultrasound). Visualisation of the superior left pulmonary vein in left atrium.
Large legend:
Fig. 12c Same case as previous figure. The stereotaxic voxel is positioned on the superior left pulmonary vein as can be seen from the comparison between the transverse scan (A) and the frontal scan (C).
1= superior left pulmonary vein; 2= superior right pulmonary vein; 3= inferior right pulmonary vein; 4= inferior left pulmonary vein.

Fig. 012d
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Fig. 012d Pregnancy at 22nd week gestation, examined by Multiplanar ultrasound (so called 3D ultrasound). Visualisation of the superior right pulmonary vein in left atrium.
Large legend:
Fig. 12d Same case as previous figure. The stereotaxic voxel is positioned on the superior right pulmonary vein as can be seen from the comparison between the transverse scan (A) and the frontal scan (C).
1= superior left pulmonary vein; 2= superior right pulmonary vein; 3= inferior right pulmonary vein; 4= inferior left pulmonary vein.

EXPERT ZONE - FETAL SKELETON

3D ULTRASOUND AND MULTIPLANAR ULTRASOUND (so called 3D ultrasound) IN THE EXAMINATION OF FETAL SKELETON:
The three dimensional and Multiplanar ultrasound (so called 3D ultrasound) allows the operator to have numerous computed graphic windows to conduct a very accurate study of the different parts of the fetal skeleton.

Graphic window of Multiplanar ultrasound (so called 3D ultrasound).
This allows a multiplanar comparison of an acquired measurement. It is especially useful to:
• Study defects of the upper jaw and evaluate the extent of palatal damage, thus providing the plastic surgeon and perinatologist the means to schedule the most suitable correction procedure once the baby is born.
• Study the defects of the neural tube. The multiplanar comparison highlights the relationship of the pathognomonic ultrasonographic report of the sagittal scan (double interrupted track) with the transverse scan (open vertebral ring).
• Evaluate limb abnormalities. Lee has reported a case of phocomelia accurately detected by 3D ultrasound examination.

Graphic windows from '3D ultrasound'
This allows an in-depth study of the pathologies above mentioned, and provides graphic instruments that may be used to illustrate and explain the pathology to the parents.
There are various filters available for the acquisition of the different details :
• Maximum transparency filter - This is most appropriate to study the skeleton, as it is able to detect the highest echogenicity of the structure;
• X-ray filter: Gives a radiographic effect to the reconstruction, thus showing the gradations or areas of different echoic response;
• Surface filter: Allows the maximum definition of the proximal points but does not provide the 'depth effect'.

Our group has studied the application of 3D ultrasound for the evaluation of cranial sutures and fontanelles (M. Iaccarino, E. Vavarigos et al - ' 3D ULTRASOUND in the study of fetal cranial sutures and fontanelle', published in 'Giornale Italiano di Ostetricia e Ginecologia - CIC Edizioni Internazionale, 1999) and has shown how 3D ultrasound is useful in the evaluation of various parts of the fetal cranium.

FIGURE SKELETON

Fig. 001a
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Fig. 001a. Pregnancy at 19th week gestation. 3D ultrasound of calvarial vault which put in evidence the bregmatic and lambdoidean fontanels.

Fig. 001b
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Fig. 001b Schematic illustration showing the upper view of the cranium showing the sutures and the fontanelle.
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Fig. 001b Graphics showing the upper view of the cranium showing the sutures and fontanelle. 1= frontal suture; 2= coronal suture 3= bregmatic fontanelle; 4= sagittal suture;5= lambdoidean suture;6= lambdoidean fontanelle; F= frontal bone; P= parietal bone; O= occipital bone. From M.Iaccarino, E. Varvarigos et al ' 3D ULTRASOUND in the study of fetal cranium anatomy.' Giornale Italiano di Ostetricia e Ginecologia. In press.

Fig. 002a
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Fig. 2a Pregnancy at 17th week gestation. Transabdominal volume examined in 3D ultrasound. Lateral vision of cranial suture and fontanelle.
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Fig. 2a Pregnancy at 17th week gestation. Transabdominal volume examined in 3D ultrasound. Lateral vision of cranial suture and fontanelle. 1= coronal suture 2= anterior fontanelle 3= lambdoidean suture 4= posterior fontanelle 5= temporal area of the external acoustic meatus; 6= frontal-sphenoidal suture. F= frontal bone; O= occipital bone; P= parietal bone; Sf = sphenoidal bone; T= frontal bone; Z= zygomatic bone.

Fig. 002b
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Fig. 002b Schematic illustration of calvarial vault-lateral view: identification of fontanelle and sutures.
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Fig. 002b Schematic illustration of calvarial vault-lateral view. 1= bregmatic fontanelle 2= coronal suture 3= sphenoidal suture 4= spheno-squamous suture; 5=squamous suture;6= petro-squamous suture 7= mastoid fontanelle 8= mendosa suture; 9= lambdoidea suture F= frontal bone; Pa= parietal bone; P= petro-temporal bone; S= sphenoidal bone T= temporal bone.

Fig. 003a
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Fig. 003a Pregnancy at 17th week gestation. Normal upper jaw evaluated by Multiplanar rendering (so called 3D ultrasound).
Large legend
Fig. 003a Pregnancy at 17th week gestation. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound). In A the red arrow shows the stereotaxic voxel placed on the upper jaw: this gives as a result the visualisation of the normal upper jaw in C (red arrows – transversal scan). Notice also the alveolar cavities in C.

Fig. 003b
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Fig. 003b Pregnancy at 17th week gestation. Normal lower jaw evaluated by Multiplanar rendering (so called 3D ultrasound).
Large legend
Fig. 3b Same case as previously. In A stereotaxic voxel (yellow arrow) is now moved down to the lower jaw, completely visible in C (red arrows). In C notice also some alveolar cavities.

Fig. 004a
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Fig. 004a Pregnancy at 23rd week gestation. Cleft palate. Multiplanar ultrasound (so called 3D ultrasound) applied to the examination of the pathologic upper jaw.
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Fig. 004a Pregnancy at 23rd week gestation. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound). In A the green arrow shows the stereotaxic voxel positioned on the upper jaw corresponding to the cleft palate: in C the stereotaxic voxel confirms the cleft lip and cleft palate. Red arrows show the residual part of the upper jaw.

Fig. 004b
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Fig. 004b Pregnancy at 23rd week gestation. 3D ultrasound. Cleft palate. Stereotaxic voxel is now positioned on the physiologic lower jaw.
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Fig. 4b Same case as previous figure. 3D ultrasound. In A (frontal scan) the yellow arrow shows the stereotaxic voxel now placed on the lower jaw which appears completely normal in C (transversal scan): red arrows mark show the whole lower jaw and its alveolar cavities.

Fig. 005
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Fig. 005 Pregnancy at 26th week gestation. 3D ultrasound. Multiplanar examination of physiologic rachis.
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Fig. 005 Pregnancy at 26th week gestation. 3D ultrasound. Examination of the physiologic rachis by Multiplanar rendering (so called 3D ultrasound). In C the red arrow shows the closed vertebral ring.

Fig. 006
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Fig. 006 Pregnancy at 24th week gestation. 3D ultrasound. Multiplanar examination of vertebral anterior and posterior ossification centres.
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Fig. 006 Pregnancy at 24th week gestation. Transabdominal volume examined by Multiplanar ultrasound (so called 3D ultrasound). In A the yellow arrow shows the height of the transversal scan shown in C. In B the yellow arrow on the left shows the spina vertebrae while the right yellow arrow shows the vertebral body ) anterior ossification centre). In C is shown the transverse scan. The graphic shows the vertebral structures that can be visualised in A. 1= vertebral body; 2= lower lamina; 3= area of back muscles, visible in part on the scan; 4= lower articulation process (comparison in plane A); 5= spinal column.

Fig. 010
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Fig. 10 Pregnancy at 21st week gestation. Spina bifida examined by Multiplanar ultrasound (so called 3D ultrasound).
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Fig. 10 Pregnancy at 21st week gestation. Transabdominal volume examined by Multiplanar ultrasound (so called 3D ultrasound). In A and B: the yellow arrows indicate the stereotaxic voxel positioned in the area of spina bifida: this position gives as a results the ultrasonographic report of 'opened ring' in C (transversal scan).

Fig. 011
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Fig. 011 Same case as previous figure. 3D ultrasound. The stereotaxic voxel is now moved on the normal part of the rachis with spina bifida
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Fig. 011 Same case as previous figure. 3D ultrasound. The stereotaxic voxel is now moved on the normal part of the rachis with spina bifida: correspondent transversal scan (C) shows the report of a normal lumbar spine with ‘closed ring’.

Fig. 12 Same case as previous figure. 3D ultrasound of the spina bifida. Click over MOVIE.

EXPERT ZONE - 1ST TRIMESTER

3D ULTRASOUND AND MULTIPLANAR ULTRASOUND (so called 3D ultrasound) IN THE FIRST TRIMESTER OF PREGNANCY
Our experience.
The first studies in 3D ultrasound applied to the first trimester were carried out in Spain by Bonilla Musoles, who highlighted how this method improves the possibility to examine the result of conception in this period. The examinations carried out using three transvaginal scans allowed the early diagnosis of cases of meningocele and encephalocele, by improving the graphics of the information provided by the ultrasonographic signals. The first studies in Italy were carried out by Dodero and Sirito in collaboration with our group. These have shown how the acquisition of transvaginal ecographic volume reduces the time needed to examine a patient. The measurements acquired were then stored on a 88 MB Syquest disc. The patient was thus examined transvaginally for a time equal to the acquisition of the measurements (about 8 to 12 seconds). Subsequently it was possible to recall the volume and examine the data or send them to an external examiner. The availability of reliable and high-capacity hardware and software tools has allowed us to reduce by 150 times the time needed for the acquisition and manipulation of the computerized information (reformatting). The latest improvement in the mechanics of probe translating (vaginal and abdominal) and the introduction of digital systems – which have replaced the analogical ones – have considerably improved the examination of significant volumes.

Figure 1ST trimester

Fig. 001a.
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Fig. 001a Pregnancy at 8 weeks 5 days gestation. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound). CRL of the fetus is measured on the sagittal scan (A).
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Fig. 001a Pregnancy at 8 weeks 5 days gestation. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound). On plane A CRL of the fetus is measured on the sagittal scan (A). In plane B (frontal scan) the upper limbs and the extra-embryonic coeloma are visualised.

Fig. 002a.
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Fig. 002a Pregnancy at 11 weeks and 5 days. 3D ultrasound. The volume is reformatted in order to visualise fetal sagittal scan on plane A: measurement of the CRL.
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Fig. 002a Pregnancy at 11 weeks and 5 days. 3D ultrasound. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound). The volume is reformatted in order to visualise fetal sagittal scan on plane A: measurement of the CRL.

Fig. 003a.
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Fig. 003a 3D ultrasound. Bi-chorionic bi-amniotic twin pregnancy at 8th weeks gestation. Large legend
Fig. 003a 3D ultrasound. Bi-chorionic bi-amniotic twin pregnancy at 8th weeks gestation. The volume is reformatted in order to measure the CRL of both fetuses in C.

Fig. 4a Pregnancy at 11 weeks and 5 days gestation. 3D ultrasound. The volume is placed and magnified: nuchal translucency in measured in plane A (sagiptal scan).

Fig. 004a.
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Fig. 004b Pregnancy in 13th week. 3D ultrasound. Transabdominal volume. Pathologic nuchal translucency in fetus affected by hygroma.
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Fig. 004b Pregnancy in 13th week. 3D ultrasound. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound) and stereotaxic voxel (or marker dot). Pathologic nuchal translucency in fetus affected by hygroma. To point out in A and C the hygroma at the height of the neck while in B and C it's possible to visualise the abnormal nuchal translucency.

Fig. 005.
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Fig. 005 Pregnancy at 5th week gestation. 3D ultrasound. Transabdominal volume examined Multiplanar rendering (so called 3D ultrasound). Arcuate uterus.
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Fig. 005 Pregnancy at 5th week gestation. 3D ultrasound. Transabdominal volume examined Multiplanar rendering (so called 3D ultrasound). On plane A (reformed coronal) an arcuate uterus is visualised: the arrow indicates the initial pregnancy at the left part of uterine fundus.

Fig. 006.
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Fig. 006. Pregnancy at 5th week gestation in sub-septate uterus. Transabdominal volume examined with Multiplanar rendering (so called 3D ultrasound).
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Fig. 006. Pregnancy at 5th week gestation in sub-septate uterus. Transabdominal volume examined with Multiplanar rendering (so called 3D ultrasound). In A (non-original, reformatted frontal scan) the sub-septate uterus: the yellow arrow shows the sub-septum which takes place in the fundus and only in a part of uterine body; the red arrow shows the initial pregnancy in the left part of the uterus. In C (transverse scan) the yellow arrow shows the sub-septum while the green arrows show the endometrium separated from the sub-septum.

Fig. 007a.
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Fig. 007a Pregnancy at 7th week gestation in septate uterus. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound).
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Fig. 007a Pregnancy at 7th week gestation in septate uterus. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound). In A (non-original, reformatted frontal scan) the septum is visualised. In the left part of the uterus pregnancy is visualised while in the right one the decidual reaction. The yellow arrow shows the septum, the red arrow the two parts of the uterus separated by the septum and the green arrow shows the embryo placed inside the gestational cavity.

Fig. 007a.
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Fig. 007b Same case as in previous figure. 3D ultrasound. The red arrows show the two parts of the uterus separated from the septum
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Fig. 007b Same case as in previous figure. 3D ultrasound. The red arrows show the two parts of the uterus separated from the septum (green arrow). The yellow arrow shows the gestational sac.

Fig. 008.
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Fig. 8 Cervical pregnancy at 5th week gestation. 3D ultrasound.
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Fig. 8 Cervical pregnancy at 5th week gestation. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound). The comparison between the 3 orthogonal planes put in evidence the cervical position of the gestational sac, visible in B (sagittal plane) and C (transverse plane).

Fig. 9 Same case as above. 3D ultrasound. Magnification of pregnancy in cervix.

Fig. 010.
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Fig. 010 Pregnancy at 10th weeks gestation. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound). The red arrows show a large area of amnio-corial detachment.
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Fig. 010 Pregnancy at 10th weeks gestation. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound). The red arrows show a large area of amnio-corial detachment. Multiplanar examination put in evidence how the placental area is normal: only a placental edge is involved in the detached area: favourable prognosis. The area of detachment was reabsorbed in a month and pregnancy has continued with the birth of a live and healthy baby. E= fetus.

Fig. 011.
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Fig. 011 Pregnancy at 13th week gestation. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound). Anencephalic fetus. Click on MOVIE.
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Fig. 011 Pregnancy at 13th week gestation. Transabdominal volume examined by Multiplanar rendering (so called 3D ultrasound). Anencephalic fetus, where the absence of the calvarium can be seen on 3 orthogonal scan.

Fig. 012.
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Fig. 12 Pregnancy at 12nd week. Transvaginal volume examined by Multiplanar rendering (so called 3D ultrasound). Exencephalic fetus.
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Fig. 12 Pregnancy at 12nd week. Transvaginal volume examined by Multiplanar rendering (so called 3D ultrasound). Exencephalic fetus. On frontal scan (A) the arrow points out the absence of calvarium and the irregular shape of the brain.

EXPERT ZONE - GENITOURINARY APPARATUS

MULTIPLANAR AND 3D ULTRASOUND APPLIED TO THE STUDY OF THE GENITO-URINARY APPARATUS.
KIDNEYS
Examinations of the kidneys are carried out using three types of computerised graphic windows:
1. '3-scan' method, to study both kidneys from the coronal, sagittal, and transverse plane, in order to evaluate the presence, structure, integration and relationships with the adjoining organs. In the second and third trimesters the tests are particularly useful to evaluate abnormalities of the kidneys and renal pelvis;
2. Three intersecting planes (less useful);
3. 3D ultrasound: Our group has adopted 3D ultrasound to study the kidney as part of a speculative study to show the possibility to obtain a 3D ultrasound of the fetal kidney (although scanning examination results more useful).
The volumetric observation can be undertaken usually on the transverse plane of the two kidneys. Sometimes the position of the fetus does not allow both kidneys to be seen at the same time, in other cases the volumetric observation is limited to the affected kidney. The 3D images of Multiplanar ultrasound (so called 3D ultrasound) are compared to those obtained with 2D ultrasound. By means of multiplanar coordinates, the operator may choose to see any point in 3D vision. In our experience the use of volumetric examinations to study the kidneys (particularly using the multiplanar window) increases the definition of the images and thus provides the echographer with a more precise diagnosis.
BLADDER
The fetal bladder, always visible on 2D ultrasound when full, can be highlighted and measured easily with 3D ultrasound. In the adult, the bladder trigon can be seen in 3D, but repeated attempts to observe the fetal bladder trigon were not successful.
The 3D examination shows the bladder on 3 simultaneous orthogonal scans. Its position can be evaluated with respect to the neighbouring organs and distinguished from the pseudocystic pathological formation situated in the ileac hollow (hydrometrocolpus, persistent cloaca, anorectal atresia). The differential diagnosis of ovarian cysts is based on the simultaneous visualisation of the female sex organs, and of bilateral cysts with a transonic content distinct from the bladder.
URETHRA
In male fetuses, the volumetric examinations of the penis show the path of the penal urethra. The fetal penis is shown on all multiplanar scans at the same time, which enables to study the course of the urethra.

LEGENDS OF FIGURES

Fig. 001.
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Fig. 001. Pregnancy at 18th week gestation. Transabdominal volume examined by Mp rendering (so called 3D ultrasound). Normal kidneys
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Fig. 001. Pregnancy at 18th week gestation. Transabdominal volume examined by Mp rendering (so called 3D ultrasound). The red arrows show the edges of the kidneys on 3 orthogonal planes.

Fig. 002.
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Fig. 002. Pregnancy in 30th week gestation. Transabdominal volume examined by Mp rendering (so called 3D ultrasound). Normal kidneys
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Fig. 002. Pregnancy in 30th week gestation. Transabdominal volume examined by Mp rendering (so called 3D ultrasound). The red arrows show the edges of the kidneys on 3 orthogonal planes.

Fig. 003. Same case as in previous figure . 3D ultrasound of the fetal kidneys. The rachis is visualised between the kidneys.

Fig. 004
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Fig. 004. Pregnancy at 32nd week gestation. Bilateral dilatation of renal pelvis. Large legend
Fig. 004. Pregnancy at 32nd week gestation. Bilateral dilatation of renal pelvis. Green arrows puts in evidence the superior and inferior edges. Red arrow marks the two renal pelvis and their enlargement (13mm).

Fig. 005. Same case as in previous figure. 3D ultrasound. The rachis is visualised between the kidneys. P = enlarged renal relvis.

Fig. 006
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Fig. 006. Pregnancy at 29th week gestation. Transabdominal volume examined by MP rendering (so called 3D ultrasound). Renal cyst.
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Fig. 006. Pregnancy at 29th week gestation. Transabdominal volume examined by MP rendering (so called 3D ultrasound). Renal cyst. In A and B the green arrows mark the superior and inferior renal edges. In C the arrows marks anterior and posterior edges. Red arrows marks the cyst.

Fig. 007
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Fig. 007. Pregnancy at 27th week gestation. Transabdominal volume examined by MP rendering (so called 3D ultrasound). Left kidney with double pelvis and duplex collecting system. Large legend
Fig. 007. Pregnancy at 27th week gestation. Transabdominal volume examined by MP rendering (so called 3D ultrasound). Left kidney with double pelvis and duplex collecting system. In A and B the red arrow marks 2 renal pelvis of the same kidney while green arrows marks the superior and inferior edges of the kidneys. In C (transversal scan) red arrows marks anterior and posterior edges of superior pelvis of left kidney; violet arrows marks anterior and posterior edges of left kidney.

Fig. 008
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Fig. 008. Pregnancy at 27th week gestation. Transabdominal volume examined by MP rendering (so called 3D ultrasound). Monolateral agenesis of right kidney.
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Fig. 008. Pregnancy at 27th week gestation. Transabdominal volume examined by MP rendering (so called 3D ultrasound). Monolateral agenesis of right kidney. Left kidney is well visualised while right kidney area results as empty. In A, on the right side of the fetus, red arrows marks superior and inferior edges of adrenal gland: a renal aplasia is therefore excluded. Comparison between A and C (transversal scan) plane clearly put in evidence left kidney while right kidney is not visualised.

Fig. 009
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Fig. 9. Same case as in fig. 7. Transabdominal volume examined by MP rendering (so called 3D ultrasound). Ectopic ureterocele in duplex collecting system.
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Fig. 9. Same case as in fig. 7. Transabdominal volume examined by MP rendering (so called 3D ultrasound). Ectopic ureterocele in duplex collecting system.
Fl = Femour; St = Stomach.

Fig. 010a
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Fig. 010a. Pregnancy at 23rd week gestation. Transabdominal volume examined by MP rendering (so called 3D ultrasound). Ectopic pelvic right kidney.
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Fig. 010a. Pregnancy at 23rd week gestation. Transabdominal volume examined by MP rendering (so called 3D ultrasound). Ectopic pelvic right kidney. Multiplanar comparison put in evidence right kidney and absence of left kidney in renal area.

Fig. 010b
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Fig. 10b. Same case as in previous figure. Stereotaxic voxel is positioned in left renal area: left kidney is not visualised.
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Fig. 10b. Same case as in previous figure. Stereotaxic voxel is positioned in left renal area: left kidney is not visualised.

Fig. 010c
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Fig. 10c. Same case as in previous figure. Stereotaxic voxel is positioned in left pelvic area: Pelvis and ureter dilatation area clearly observed.
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Fig. 10c. Same case as in previous figure. Stereotaxic voxel is positioned in left pelvic area: frontal (A), sagiptal (B) and transversal (C) scan of left kidney are obtained. Pelvis and ureter dilatation area clearly observed.

EXPERT ZONE - UTERUS

MULTIPLANAR AND 3D ULTRASOUND IN GYNAECOLOGY: THE UTERUS
Introduction.
The use of 3D ultrasound techniques in gynaecology, particularly in the evaluation of the uterus, have introduced the so-called 'third scan' or frontal plane. This scan was not available with the conventional bidimensional ultrasound and is actually obtained selecting an ideal scan (chosen by the operator) and allowing calculation by V-Mode equipment workstation: Thus a “virtual” scan is visualized on the monitor.
The information provided by this virtual scan, and moreover the possibility to compare each single voxel on the three orthogonal intersected scans, provides the operator with better diagnostic tools in the following cases:

1. The physiological uterus – to evaluate the endometrium, the position of an IUD etc.
2. Identification of
· Primitive uterine malformations: Bicornuate, unicornuate, septated and subseptated uterus;
· Benign and malignant secondary uterine malformation: Neoformations, endometriosis etc.
On this page we show the advantages of using three dimensional and Multiplanar ultrasound (so called 3D ultrasound) to examine the physiological and pathological uterus.

LEGENDS OF UTERUS

Fig. 001
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Fig. 001 Transvaginal volume, examined by Multiplanar ultrasound (so called 3D ultrasound). Normal uterus: the so called ‘third plane’ (frontal plane).
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Fig. 001 Transvaginal volume, examined by Multiplanar ultrasound (so called 3D ultrasound). Normal uterus: the so called ‘third plane’ (frontal plane). Notice in C (non original reformatted frontal scan) the uterine fundus shown by the arrows.

Fig. 002a Transvaginal volume, examined by Multiplanar ultrasound (so called 3D ultrasound). IUD normal position. In A it is possible to see one of the two arms (the left) of the T-shaped IUD.

Fig. 002b Same case as in previous figure. 3D ultrasound of IUD. Surface filter. T-shaped IUD is clearly visualised.

Fig. 003a Transvaginal volume examined by Multiplanar ultrasound (so called 3D ultrasound). Sub-mucous uterine leiomyoma. Notice in A the sub-mucous fundal location of the leiomyoma.

Fig. 003b Transvaginal volume. 3D ultrasound with surface filter. Sub-mucous uterine fibroid.

Fig. 003c Same case as before: minimum transparency filter is applied. Click here to see 3D ultrasound MOVIE.

Fig. 003d Transabdominal volume, taken on 3 scans. Sub mucous uterine fibroid in virginal patient undergoing routinely examination.

Fig. 003e Same case as in previous figure. Transabdominal volume examined by Multiplanar ultrasound (so called 3D ultrasound). Sub-mucous uterine fibroid.

Fig. 004a
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Fig. 004a. Trans-abdominal volume examined by Multiplanar ultrasound (so called 3D ultrasound) of a 12 years old patient affected by marked pelvic pains. Unperforated hymen. Large legend
Fig. 004a. Trans-abdominal volume examined by Multiplanar ultrasound (so called 3D ultrasound) of a 12 years old patient affected by marked pelvic pains. Unperforated hymen with enlarged vagina due to hematic raising: confirmed at vaginal examination of the patient. Notice how vaginal enlargement is better appreciated on the non original reformatted frontal scan. Vaginal enlargement markedly involves both the 2 lateral fornix: this observation explains the intensive pains.

Fig. 004b Transabdominal volume. Hypoplastic uterus of a 22 years old patient affected by primitive amenorrhea.

Fig. 004c
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Fig. 004c Transvaginal volume examined by Multiplanar ultrasound (so called 3D ultrasound). Uterine and endometrial evaluation of menopausal woman undergoing HRT.
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Fig. 004c Transvaginal volume examined by Multiplanar ultrasound (so called 3D ultrasound). Uterine and endometrial evaluation of menopausal woman undergoing HRT. In A (frontal plane) it is possible to visualise part of the uterine fundus (red arrows). In B and C a measurement of the endometrium has been performed: compatible with the anamnesis.

Fig. 005a. Trans-abdominal volume of arcuate uterus examined by MP rendering (so called 3D ultrasound). Virginal patient. In A the frontal scan clearly states the presence of the fundal arcuate shape.

Fig. 005b
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Transvaginal volume examined by MP rendering (so called 3D ultrasound). Arcuate uterus.
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Fig. 005b Transvaginal volume examined by MP rendering (so called 3D ultrasound). Arcuate uterus. In C The arrows shows the endometrium which is divided in the upper part of the uterine cavity. Visualisation of the frontal scan enables the visualisation of the arcuate uterine fundus.

Fig. 006a
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Fig. 006a Transvaginal volume examined by MP rendering (so called 3D ultrasound). Sub-septate uterus. Large legend
Fig. 006a Transvaginal volume examined by MP rendering (so called 3D ultrasound). Sub-septate uterus. In A 1 and A2 (transversal scan) the endometrium is visualised: the uterine septum divides in two the upper part of uterine cavity; in C however, the non-original reformatted frontal scan is clearly seen. The curved arrow shows the septum dividing in 2 the upper part of uterine cavity. In B (sagittal scan): the arrow S put in evidence the sub-septum.

Fig. 6b Same case as the previous figure examined by MP rendering (so called 3D ultrasound). In D can be seen the septum shown by the arrow and uterine cavity divided in two parts.

Fig. 007
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Fig. 007. Transvaginal volume. Multiplanar rendering (so called 3D ultrasound). Septate uterus.
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Fig. 007. Transvaginal volume obtained from old Combison 530 machine. Multiplanar rendering (so called 3D ultrasound). Septate uterus. In A (Non original reformatted frontal scan) the arrow marks the uterine septum which completely divides the uterine cavity. In C (transverse scan) the two red arrows show the endometrium divided by the septum (yellow arrow).

Fig. 008
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Fig. 008 Same case as in previous figure. Septate uterus. 3D ultrasound. Large legend
Fig. 008 Same case as in previous figure. Septate uterus. 3D ultrasound with light gradient filter. The filter increases the contrast between the structures: a better view of the septum is obtained (red arrow).

Fig. 009 Same case as previous figure. 3D ultrasound with maximum transparency filter.

Fig. 010 Same case as previous figure. 3D ultrasound with surface filter.

Fig. 011
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Fig. 11 Transvaginal volume, examined by MP rendering (so called 3D ultrasound). Unicornuate uterus. Large legend
Fig. 11 Transvaginal volume, examined by MP rendering (so called 3D ultrasound). Unicornuate uterus: our original case. In A (frontal scan) the red arrows indicate the missing horn, while the yellow ones put in evidence the single horn, typically leaning to the right. These images are not obtainable in B-mode ultrasound. In B the corresponding sagittal plane shows the endometrial bilayer (arrows). On the lower right: 3D ultrasound of the unicornuate uterus, using X ray filter. The left ovary was not visualised even after intestinal preparation and clyster. The case was subsequently confirmed at hysterosalpingoscopy.

Fig. 011
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Fig. 011b Same case as in previous figure. Hysterosalpingoscopy which confirms previous suspect of unicornuate uterus.
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Fig. 011b Same case as in previous figure. Hysterosalpingoscopy of the unicornuate uterus which confirms previous suspect of unicornuate uterus.

Fig. 012a
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Fig. 012a Transabdominal volume examined by MP rendering (so called 3D ultrasound). Bicornuate uterus and ovarian cysts diagnosed in a virginal patient after V-Mode routinely examination.
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Fig. 012a Transabdominal volume examined by MP rendering (so called 3D ultrasound). Bicornuate uterus and ovarian cysts diagnosed in a virginal patient after V-Mode routinely examination for pelvic pains. In A and C (frontal scan) the bicornuate uterus is visualised and the two horns are numbered. In B and C an ovarian cyst is visualised in the Douglas.

Fig. 012b
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Fig. 12b Transvaginal volume examined by MP rendering (so called 3D ultrasound). Bicornuate uterus.
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Fig. 12b Transvaginal volume examined by MP rendering (so called 3D ultrasound). Bicornuate uterus. The graphic put in evidence the silhouette of the 3D image.
1= right horn; 2= left horn; C =uterine cervix. O = Right ovary.

Fig. 013
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Fig. 013 Transabdominal volume examined by MP rendering (so called 3D ultrasound). Endometrial benign neoplasm (polyp).
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Fig. 013 Transabdominal volume examined by MP rendering (so called 3D ultrasound). Endometrial benign neoplasm (polyp). The yellow arrows show the endometrium and the location of the polyp (red arrows). The result of the histological examination was endometrial hyperplasia.

Fig. 014
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Fig. 014 Same case as previous figure. 3D ultrasound with surface filter. Large legend
Fig. 014 Same case as previous figure. 3D ultrasound with surface filter. The red arrows indicate the margins which separate the miometrium and the endometrium. The yellow arrow shows the endometrial polyp and clearly the margins.

Fig. 015
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Fig. 015 Transvaginal volume examined by Mp rendering (so called 3D ultrasound). Endometrial polyp.
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Fig. 015 Transvaginal volume examined by Mp rendering (so called 3D ultrasound). Endometrial polyp. The yellow arrows indicate the endometrial polyp. Result of histological examination: endometrial hyperplasia.

Fig. 016
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Fig. 16 Same case as previous figure. 3D-rendering.
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Fig. 16 Same case as previous figure. 3D-rendering with surface filter. The yellow arrow shows the endometrial polyp with slightly irregular but clear margins.

Fig. 017
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Fig. 017 Transvaginal volume examined by MP rendering (so called 3D ultrasound). Endometrial carcinoma.
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Fig. 017 Transvaginal volume examined by MP rendering (so called 3D ultrasound). Endometrial carcinoma. In B the yellow arrows show the rear part of the carcinoma in which no areas of myometrial infiltration are visualised. The red arrows show the area of carcinoma infiltration in the anterior part of myometrial walls.

Fig. 018
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Fig. 018 Same case as previous figure. The diameter of the endometrium is measured on the sagittal scan: size (17.4 mm)
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Fig. 018 Same case as previous figure. The diameter of the endometrium is measured on the sagittal scan: size (17.4 mm) is greater than normal for a woman of 77 in menopause who has not undergone to HRT.

EXPERT - OVARIAN ANNEXES

MULTIPLANAR AND 3D ULTRASOUND IN GYNAECOLOGY - THE OVARY
The use of 3D ultrasound to study the ovary is still under examination. Feichtinger used 3D in infertile patients who had undergone ovarian stimulation to evaluate the volume of single cavity follicles. An indirect measurement of the volume was made; consequently, the follicle was aspirated and the actual volume of the follicular liquid was calculated.
Following are the details of the three scans needed for the examination of an ovary:
• To evaluate the correct position of the neighboring pelvic structure; in our experience this option is very useful to evaluate structures compatible with paraovarian cysts. (see fig.)
• Using the voxel point in multiplanar comparisons, to see any point of the ovary on three multiplanar scans at the same time. This option is particularly useful to study the ovarian mass, the structure of which, whether solid, multiloculated or complex, may be examined even with scans not available in B mode.
• Using 3D power, which allows to map the vessels of the neo-formation; this technique still presents some technical limitations related to the time of acquisition of the image, although the introduction of new digital vaginal ultrasound and the new MT software seems to have overcome this problem.

It is possible to obtain a power 3D ultrasound of the ovarian mass vessels: This option seems to be useful to evaluate neoplastic ovarian masses (Kurijak A., Kupesic S. et al. 1999)

LEGENDS – OVARY

Fig. 001
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Fig. 1 Trans-abdominal volume examined by MP rendering (so called 3D ultrasound). Policystic ovarian disease (PCOD).
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Fig. 1 Trans-abdominal volume examined by MP rendering (so called 3D ultrasound). Policystic ovarian disease (PCOD). The patient, who was virgin, complained of irregular menstruation, acne, hypertrichosis and slight hirsutism. The ultrasonographic examination clearly revealed the condition of the two ovaries (A and C), and their position respect of the uterus (B – arrow).

Fig. 002
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Fig. 2 Transabdominal volume. MP rendering (so called 3D ultrasound). Para-ovarian cysts.
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Fig. 2 Transabdominal volume. MP rendering (so called 3D ultrasound). Para-ovarian cysts. In A (longitudinal oblique scan) the cyst is close to a structure compatible with the ovary. From her case history we learn that the patient had undergone to E/P therapy for three months without result. Paraovarian cysts was suspected, later confirmed at laparoscopic surgery. Po = right paraovarian cyst ; Ov= right ovar