Feasibility of performing a virtual patient examination using three-dimensional ultrasonographic data acquired at remote locations.

OBJECTIVE: To evaluate the feasibility of performing three-dimensional ultrasonographic studies that meet American Institute of Ultrasound in Medicine and American College of Radiology ultrasonographic examination guidelines with review off-line and at remote locations. METHODS: One hundred patients were studied at 2 institutions using high-end two-dimensional clinical ultrasonographic scanners and commercially available three-dimensional ultrasonography for a variety of organ systems (first- and second-trimester fetus, abdomen, and female pelvis). We evaluated several parameters, including measurements, completeness of organ visualization, abnormalities identified, image quality, number of volumes required, and discrepancies between interpretations. RESULTS: Overall, three-dimensional ultrasonography could produce diagnostic-quality results comparable with those of two-dimensional ultrasonography. Three-dimensional ultrasonographic image quality was lower than that of two-dimensional ultrasonography. Two- and three-dimensional ultrasonographic measurements were comparable (<5% difference), as was the extent of organ visualization, although some structures were challenging for both two- and three-dimensional ultrasonography. In general, organs completely imaged in the scanner field of view required 1 to 1.5 volumes, whereas larger organs required between 3 and 6 volumes. Differences among reviewers' interpretations highlighted the need for standardization of acquisition and reviewing protocols for sonographers and physicians. CONCLUSIONS: Our results show that it is clinically feasible to acquire three-dimensional ultrasonographic data at one site and to obtain accurate interpretation by off-line review at another within the context of providing high-quality clinical diagnostic studies.

The single umbilical artery in a high-risk patient population: what should be offered?

OBJECTIVE: To determine whether fetal echocardiography is warranted in cases of single umbilical artery in a population at risk for aneuploidy. METHODS: All cases of fetal single umbilical artery identified over a 2-year period were reviewed for other sonographically detected abnormalities, fetal echocardiographic results, and karyotype. RESULTS: Sixty-five cases of single umbilical artery were diagnosed on the basis of initial sonograms. Five were subsequently shown to have 3-vessel cords (8% false-positive diagnosis; incidence, 1.2%). Excluding 3 from twin gestations, 57 cases formed the study population. Thirty-one fetuses (54%) were initially thought to have isolated single umbilical arteries, and 26 (46%) had nonisolated single umbilical arteries. Fetal echocardiography was performed in 29 cases (51%), 24 (83%) with normal findings and 5 (17%) with abnormal findings. Four (50%) of 8 nonisolated single umbilical arteries had abnormal echocardiographic findings versus 1 (5%) of 21 apparently isolated single umbilical arteries (P < .05; odds ratio, 20). Karyotypes in 36 cases (63%) showed 25 (69%) euploid and 11 (31%) aneuploid fetuses. An apparently isolated single umbilical artery was never associated with an abnormal karyotype. Eleven (50%) of 22 fetuses with nonisolated single umbilical arteries had aneuploidy (P < .005). The side of the missing umbilical artery did not correlate with other sonographically detected abnormalities, abnormal fetal echocardiographic findings, or aneuploidy. CONCLUSIONS: The rate of cardiac malformations seen with apparently isolated single umbilical arteries is significant, and fetal echocardiography should be performed.

New modalities for imaging the fetal heart.

Improvement in the prenatal diagnosis of congenital heart disease requires familiarity with advances ultrasound equipment and features and any new imaging methods that can effectively provide cardiac information from the fetus. This article discusses imaging the fetal heart with transvaginal ultrasound, Doppler ultrasound, intrauterine sonography, three-dimensional ultrasound (3DUS) and magnetic resonance imaging.

Evaluation of the lower extremity veins in patients with suspected pulmonary embolism: a retrospective comparison of helical CT venography and sonography. 2000 ARRS Executive Council Award I. American Roentgen Ray Society.

OBJECTIVE: In patients undergoing a combined CT angiographic and CT venographic protocol, the accuracy of helical CT venography for the detection of deep venous thrombosis was compared with that of lower extremity sonography. MATERIALS AND METHODS: Patients who had undergone a combined CT angiographic and CT venographic protocol and sonography of the lower extremities within 1 week were identified. The final reports were evaluated for the presence or absence of deep venous thrombosis. Statistical measures for the identification of deep venous thrombosis with helical CT venography were calculated. In each true-positive case, the location of the thrombus identified with both techniques was compared. All false-positive and false-negative cases were reviewed to identify the reasons for the discrepancies. RESULTS: Seventy-four patients were included. There were eight patients (11%) with true-positive findings, 61 patients (82%) with true-negative findings, four patients (5%) with false-positive findings, and one patient (1%) with a false-negative finding. When comparing helical CT venography with sonography for the detection of lower extremity deep venous thrombosis, the sensitivity measured 89%; specificity, 94%; positive predictive value, 67%; negative predictive value, 98%; and accuracy, 93%. Of the eight true-positive cases, five had sites of thrombus that were in agreement on both CT venography and sonography. Of the five discordant cases, four were false-positives and one was a false-negative. Possible explanations for all discrepancies were identified. CONCLUSION: Compared with sonography, CT venography had a 93% accuracy in identifying deep venous thrombosis. However, the positive predictive value of only 67% for CT venography suggests that sonography should be used to confirm the presence of isolated deep venous thrombosis before anticoagulation is initiated. In addition, interpretation of CT venography should be performed with knowledge of certain pitfalls.

Fetal lip and primary palate: three-dimensional versus two-dimensional US.

PURPOSE: To determine if three-dimensional (3D) ultrasonography (US) improves the ability to define the location and extent of facial clefting prenatally compared with two-dimensional (2D) US. MATERIALS AND METHODS: Thirty-one fetuses suspected of having a facial cleft were examined prospectively with 2D and 3D US. Follow-up was performed in all fetuses. RESULTS: Twenty-eight fetuses had a cleft lip at birth. The location of the cleft lip was correctly identified in all fetuses with 3D US and in 26 of 28 with 2D US. Twenty-two fetuses had a cleft primary palate. Nineteen and nine of 22 cleft palates were identified by using 3D and 2D US, respectively. Three fetuses suspected of having a facial cleft at 2D US had a normal palate at 3D US and at birth. CONCLUSION: Three-dimensional US is useful to identify the location and extent of facial clefting. The advantages of 3D US are the following: (a) The face may be viewed in a standard orientation, (b) the defect may be viewed systematically by using an interactive display, and (c) the rendered image provides landmarks for the planar images. Patient decisions may be affected, since they can view the abnormality on a recognizable 3D rendered image.

Fetal skeletal dysplasia: three-dimensional US--initial experience.

PURPOSE: To compare the prenatal ultrasonographic (US) features of skeletal dysplasia by using two-dimensional (2D) and three-dimensional (3D) US to determine whether 3D US can reveal additional diagnostic information. MATERIALS AND METHODS: Seven pregnant women suspected of having skeletal dysplasia were examined by using 2D US and 3D US. Data regarding the thorax, spine, face, limbs, hands, and feet were compared. Multiplanar and volume-rendered US images were evaluated. RESULTS: The skeletal dysplasias studied included camptomelic dysplasia (n = 2), thanatophoric dysplasia (n = 1), osteogenesis imperfecta (n = 1), arthrogryposis (n = 2), and short-limbed dysplasia (n = 1). Three-dimensional US, by allowing review in a standard anatomic orientation, was better than 2D US in depicting abnormal spatial relationships such as short ribs, splayed digits, and absent bones. Three-dimensional US enabled the acquisition of additional information in two fetuses with facial abnormalities and in two fetuses with scapular aplasia or hypoplasia (one fetus had both facial and scapular anomalies); it enabled a specific diagnosis in one fetus. The archiving capabilities of 3D US allow the review and manipulation of data after the patient has left the clinic. CONCLUSION: In three of seven patients, 3D US provided additional information in the evaluation of skeletal dysplasias, as compared with 2D US.

Three-dimensional ultrasound in the evaluation of fetal anomalies.

OBJECTIVES: To determine the additional information and clinical impact provided by three-dimensional ultrasound (3D US) imaging of fetal anomalies compared to conventional 2-dimensional ultrasound (2D US). MATERIALS AND METHODS: Sixty-three patients with 103 anomalies were scanned prospectively with both 2D and 3D US. Each anomaly was reviewed by one or more fetal imaging specialists to determine whether the 3D US data were advantageous, equivalent, or disadvantageous when compared with 2D US images. Clinical impact and pathologic or clinical outcome were determined in all cases. RESULTS: The 3D US images provided additional information in 53 anomalies (51%), were equivalent to 2D US images in 46 anomalies (45%), and were disadvantageous in four anomalies (4%). The 3D US was most helpful in evaluating fetuses with facial anomalies, hand and foot abnormalities and axial spine and neural tube defects. Planar images derived from 3D US volume data sets generally were more helpful for diagnostic purposes, whereas rendered 3D US images were more useful as a point of reference and were better appreciated by patients in understanding fetal abnormalities. Additional information provided by 3D US images impacted clinical management in 5% of patients. The 3D US images were disadvantageous in two fetuses with multiple anomalies and two with cardiac anomalies. CONCLUSION: The 3D US offered diagnostic advantages in about one-half of the selected cases studied and had effect on patient management in 5% of cases. This modality can be a powerful adjunctive tool to 2D US in providing a more comprehensible, 3D US impression of congenital anomalies. Thus, 3D US is currently most helpful as a targeted study complementing 2D US.

Artifacts and the visualization of fetal distal extremities using three-dimensional ultrasound.

OBJECTIVES: To demonstrate that acoustic shadowing in 3D US may give rise to artifacts simulating limb defects and provide a solution to eliminate its occurrence. METHODS: Twenty second trimester fetuses (gestational age 15-24 weeks) were scanned with three-dimensional ultrasound (3D US) using a sagittal acquisition plane. Fetal tibia/fibula and radius/ulna pairs were assessed for completeness of imaging. A further 20 fetuses (gestational age 20-26 weeks) were scanned in both axial and sagittal planes and the results compared to verify clear visualization of both bones. RESULTS: Shadowing from adjacent structures produced an apparent limb defect in 55% of the first 20 fetuses imaged only sagittally (18% of limb pairs). Acquiring data from more than one orientation avoided this artifact. CONCLUSIONS: The 3D US is subject to the same artifacts as two-dimensional (2D US) in terms of acoustic shadowing, although their presentation may be different. Awareness of this fact is essential for correct interpretation of 3D US studies. Three-dimensional scanning protocols should be modified to ensure that fetal structures are adequately visualized by acquiring volume data in more than one acquisition orientation.

Utility of minor ultrasonographic markers in the prediction of abnormal fetal karyotype at a prenatal diagnostic center.

OBJECTIVE: This study was undertaken to assess the value of minor ultrasonographic markers in predicting significant karyotypic abnormalities. STUDY DESIGN: A total of 2743 fetuses (14-24 weeks' gestation) prospectively underwent a detailed ultrasonographic survey before genetic amniocentesis. Criteria for 8 minor ultrasonographic markers were established. Odds ratios for significant karyotypic abnormalities in the presence of minor ultrasonographic markers were calculated with the chi(2) and Fisher exact tests. RESULTS: Of the fetuses, 14.6% had a single minor ultrasonographic marker, 2.1% had >/=2 minor ultrasonographic markers, and 2.7% had >/=1 major ultrasonographic abnormality. One hundred four fetuses (3.8%) had an abnormal karyotype. Compared with a normal ultrasonographic examination result a single minor ultrasonographic marker increased the risk of karyotypic abnormality 5.7-fold (95% confidence interval, 3.5-9.3), whereas multiple minor markers increased the risk of an abnormal karyotype 12-fold (95% confidence interval, 5.5-26.5). When they were identified ultrasonographically in isolation, echogenic bowel, 2-vessel umbilical cord, echogenic intracardiac foci, choroidal separation, and choroid plexus cysts were statistically associated with an abnormal karyotype. When minor markers were identified in clusters of >/=2, echogenic bowel, short femur, 2-vessel umbilical cord, echogenic intracardiac foci, and mild ventriculomegaly were significantly predictive of karyotypic abnormality. With respect to the a priori aneuploidy risk of 1:26 and the a priori Down syndrome risk of 1:50, a normal ultrasonographic examination result reduced the risks to 1:67 and 1:120, respectively. The use of minor ultrasonographic markers in addition to major ultrasonographic abnormalities increased the detection of karyotypic abnormality from 27.9% to 68.3%. For trisomy 21 the sensitivity rose from 16.4% to 67. 3%. CONCLUSIONS: Significant karyotypic abnormality risk assessment by ultrasonography was greatly enhanced by the addition of minor ultrasonographic markers. Further, clusters of minor ultrasonographic markers greatly increased the likelihood of karyotypic abnormality compared with a single minor marker. A completely normal ultrasonographic examination result reduced the risk of an abnormal karyotype by 62%. Inclusion of minor ultrasonographic markers in the genetic sonogram in a high-risk population will allow the detection of 68% of fetuses with karyotypic abnormalities with a false-positive rate of 17%.

Prevalence of aneuploidy with a cardiac intraventricular echogenic focus in an at-risk patient population.

The objective of this study was to determine the relative risk for aneuploidy in the presence of a cardiac intraventricular echogenic focus in a patient population at high risk for aneuploidy. A retrospective cohort study was conducted on patients referred to a fetal diagnostic center who were undergoing amniocentesis. Records and second trimester sonograms were reviewed. Approximately 5100 comprehensive prenatal sonograms were obtained over a 2 year study period. Karyotyping by amniocentesis was done in 2412 women; 84 of the karyotypes (3.5%) were abnormal. Fetuses with no ultrasonographic findings suggestive of aneuploidy had a 1.4% (28 of 1940) prevalence of significant chromosomal abnormalities. An intraventricular echogenic focus was found in 149 of the women with karyotype analysis; 15 had an abnormal karyotype. Fetuses with intraventricular echogenic foci had a relative risk of 3.30 of aneuploidy when compared to fetuses without echogenic cardiac foci. The presence of an isolated intraventricular echogenic focus carried a relative risk of 4.08 compared to those fetuses in which ultrasonography had no finding associated with aneuploidy. In conclusion, these preliminary data indicate that presence of an intraventricular echogenic cardiac focus carries an increased risk of fetal aneuploidy.

Three-dimensional ultrasound examination of the fetal hands: normal and abnormal.

PURPOSE: To assess particular features of fetal hand evaluation using three-dimensional ultrasound, and to determine whether any advantage is offered by three-dimensional over two-dimensional ultrasound in fetal hand evaluation. METHODS: Three-dimensional fetal data were collected prospectively from 44 hands in 40 fetuses from a predominantly high-risk patient population. All had a concurrent two-dimensional ultrasound examination of the hands. Diagnoses from two- and three-dimensional ultrasound examinations were compared and additional information from the three-dimensional volume assessment was noted. Three-dimensional assessment of distal forearm bones, wrist position, finger configuration and number of metacarpals and digits was recorded. RESULTS: Hands were appropriately identified as normal (32/32) or abnormal (12/12) by both two- and three-dimensional ultrasound. Three-dimensional ultrasound provided additional information when compared to two-dimensional ultrasound in both normal and abnormal hands, including the provision of three orthogonal planes with one volume acquisition, allowing rotation of the volume so that hands could be evaluated in planes not possible during two-dimensional imaging, assessment of a hand with loosely curled fingers as normal, the ability to evaluate thumb and fingers simultaneously, and improved assessment of abnormal hands. CONCLUSIONS: Three-dimensional ultrasound offers the potential to provide greater information in fetal hand evaluation for both normal and abnormal hands.

Three-dimensional ultrasonography of the fetal distal lower extremity: normal and abnormal.

The objective of this study was to compare two-dimensional and three-dimensional ultrasonographic evaluation of fetal distal lower extremities. Data from two-dimensional and three-dimensional ultrasonographic examinations from 40 distal lower extremities in 33 fetuses from a predominantly high-risk patient population were compared. Three-dimensional ultrasonography routinely provided three orthogonal planes (coronal, sagittal, and axial) for distal lower extremity evaluation. Specific features of distal lower extremity evaluation were not different using two-dimensional and three-dimensional ultrasonography. Rotation of the rendered volume provided assistance in assessing all but one of 40 distal lower extremities. Time from image acquisition to assessment for two views (coronal and sagittal) was longer with three-dimensional ultrasonography (8.2 min) than with two-dimensional ultrasonography (3.2 min). Confidence in the diagnosis of abnormal distal lower extremities was slightly improved using three-dimensional ultrasonography compared to two-dimensional ultrasonography. Pregnancy management was assisted in three of the four cases with isolated limb anomalies. In conclusion, three-dimensional ultrasonography improves the ability to evaluate the fetal distal lower extremity because of the multiplanar nature of volume assessment and the ability to rotate volume data sets. In addition, it provides assistance in counseling families, particularly for cases involving isolated limb anomalies.

Three-dimensional ultrasonography of normal fetal heart: comparison with two-dimensional imaging.

Thirty-one high-risk patients (16 to 35 weeks' gestation) underwent two-dimensional and three-dimensional ultrasonography to compare two-dimensional and non-cardiac-gated three-dimensional ultrasonography of the normal fetal heart. After normal two-dimensional studies, three-dimensional sonographic volumes were acquired without cardiac gating in transverse and longitudinal planes. Standard cardiac views were derived from three-dimensional data, analyzed, and rated as follows: (1) not identifiable, (2) identifiable but inadequate for diagnosis, (3) adequate, and (4) excellent. Two-dimensional ultrasonography demonstrated better yields of diagnostically acceptable images of basic echocardiographic views (four-chamber view, 100% for two-dimensional sonography versus 10 to 71% for three-dimensional sonography; right ventricular outflow tract, 42% for two-dimensional versus 6 to 26% for three-dimensional ultrasonography; left ventricular outflow tract, 71% for two-dimensional versus 13 to 45% for three-dimensional sonography). In one subject three-dimensional ultrasonography was superior to two-dimensional sonography in demonstrating an outflow tract. Aortic and ductal arches were not imaged with the two-dimensional technique but were available from the acquired three-dimensional volumes in 3 to 32% and 23%, respectively. False-positive and false-negative findings were observed on three-dimensional ultrasonograms. Overall, compared to two-dimensional ultrasonography, non-cardiac-gated three-dimensional sonography yielded inadequate reconstructed image quality of basic echocardiographic views (four-chamber view, right ventricular outflow tract, left ventricular outflow tract). Three-dimensional ultrasonography, however, shows potential for allowing nonechocardiographers to acquire some diagnostically acceptable views of the aortic and ductal arches.

False-positive diagnosis of spina bifida in a fetus with triploidy.

BACKGROUND: Neural tube defects can be difficult to diagnose using ultrasound. Cranial markers, such as the lemon and banana signs, are useful sonographic findings that alert the ultrasonographer to examine the spine more carefully. The false-positive rate for the banana sign has been reported previously as zero. CASE: A patient with elevated maternal serum alpha-fetoprotein presented for a fetal ultrasound examination. Findings on the scan included a lemon sign, a banana sign, an effaced cisterna magna, and splayed lumbar vertebrae. After pregnancy termination, no spinal abnormality was detected on autopsy. X-rays of the fetal spine demonstrated narrowing in the thoracic spine. The karyotype of the fetus was 69,XXY. CONCLUSION: The sonographic cranial findings suggestive of a neural tube defect were misleading in this case.

Three-dimensional ultrasound: display modalities in obstetrics.

Three-dimensional ultrasound (3DUS) has recently been introduced into clinical practice. Various techniques are available for display of the volume data. We review the importance of selecting the proper display option and rendering mode depending on the specific diagnostic question. Current display options include (1) arbitrary planar images similar to conventional two-dimensional US images, (2) surface rendering with emphasis on soft tissues or skeletal detail, (3) stereo viewing using liquid crystal glasses or red/blue glasses, and (4) cine review of gated studies. Rotation of volume data also is important in understanding/comprehending patient anatomy. The range of rotation angles varies depending on the clinical setting. Also data storage requirements increase as the number of views increases.

Three-dimensional ultrasound of the fetal spine.

OBJECTIVE: To describe normal fetal spinal anatomy displayed by three-dimensional ultrasound and to determine whether three-dimensional ultrasound improves visualization of specific spinal defects. METHODS: Fetuses (n = 28) (16 normal and 12 abnormal) were examined on standard two- and three-dimensional sonographic equipment. RESULTS: In 15 of 16 normal fetuses, the spine was visualized at least from the upper thoracic area to the lower sacrum in a single three-dimensional image, and in 14 normal fetuses continuity of the ribs and spine was depicted. Neural tube defects were identified on both two- and three-dimensional ultrasounds; however, three-dimensional ultrasound displayed the level of the defect more accurately in three of the five cases. Scoliosis was recognized easily on a single three-dimensional rendered image, whereas several two-dimensional redered image, whereas several two-dimensional images were needed for the examiner mentally to reconstruct the scoliosis. CONCLUSION: Three-dimensional ultrasound may become an important tool for imaging of the fetal spine. Additional studies are necessary to determine the efficacy and cost effectiveness of this technology. However, our preliminary data suggest that presentation of the spine as a continuous structure rather than in independent two-dimensional views makes visualization of the spatial relationship of the spinal anatomy and adjacent structures easier. The ability to review the volume data using techniques not available on two-dimensional ultrasound may enable physicians to determine the extent of neural tube defects with more accuracy.

Digital tapping of the superficial temporal artery: significance in carotid duplex sonography.

To determine whether tapping on the superficial temporal artery correctly identifies the ECA during carotid sonography, prospective evaluation of the reflection of the temporal tap on the spectral waveform was recorded and graded as 3+, 2+, 1+, or 0 in each ECA, ICA, and CCA, with 3+ being the most brisk response in each carotid system (ipsilateral CCA, ICA, and ECA). The pattern of response was evaluated in patients with and without hemodynamically significant (> than 50% diameter) stenoses in CCA, ICA, and ECA. The most frequent pattern of response to tapping on the superficial temporal artery was 3+ in the ECA, 2+ in the CCA, and 1+ or 0 in the ICA. This pattern was found in 41% (82/200) of systems overall. Whether or not stenoses were present in any branch of the extracranial carotid system, the strongest response (3+) was found in the ECA (58/200 [87%] with stenosis; 119/200 [89%] without stenosis, and lesser responses in the other arteries: 2+ in the CCA 31/200 [46%] with stenosis; 63/200 [47%] without stenosis, and 1+ or 0 in the ICA 58/200 [87%] with stenosis and 103/200 [77%] without stenosis). This pattern was unaltered by the degree of stenosis in the ECA or in the ICA. In 92.5% of the systems interrogated, the response was greater in the ECA than in the ICA. Tapping on the superficial temporal artery may be used as a reliable method of identifying the ipsilateral ECA even in instances of significant atherosclerotic disease in the ECA, CCA, or ICA.

Sonography of the fetal spine: technique, imaging findings, and clinical implications.

Sonographic evaluation of the fetal spine is an essential part of any fetal survey, and it is included in the current American Institute of Ultrasound in Medicine/American College of Radiology and American College of Obstetrics and Gynecology guidelines for obstetric sonography [1, 2]. In this paper, we review the current knowledge of anatomy of the normal fetal spine and the sonographic findings associated with spinal anomalies, with special emphasis on neural tube defects. Important cranial clues to a spine abnormality initially may be more obvious at sonography than the spine abnormality itself, and the general significance of these clues is provided. The expanding role of prenatal maternal serum and amniotic fluid testing is explored, as are the benefits and modifications these bring to sonographic evaluations. Finally, the potential benefits of the rapidly advancing technology of three-dimensional sonography are introduced.

Cephalocele detection in utero: sonographic and clinical features.

Sonographic and clinical features of 26 fetal cephaloceles were reviewed retrospectively. The most frequent reason for referral was elevated maternal serum alpha-fetoprotein levels. The smallest lesion identified was 0.4 x 0.5 cm (frontal, at 20 weeks); the largest was 9.0 x 10.0 cm (frontal, at 27 weeks). Twenty-four of 26 cephaloceles were detected on prenatal ultrasound examination; in 13 of these, more than 50% of the intracranial contents were exteriorized. Fifteen of 24 cephaloceles detected prenatally had a sulcal pattern (identified between 16 and 36 weeks' gestation); five were solid without a sulcal pattern (identified between 13 and 21 weeks' gestation), three were cystic, and one underwent a change in appearance from solid at 21 weeks to cystic at 26 weeks. Other cranial features were evaluated and included visible skull defect, seen in 23/24 (96%), ventriculomegaly, in 6/26 (23%); microcephaly, in 12/24 (50%); beaked tectal plate, in 6/16 (38%); and flattened basiocciput, in 9/24 (38%). Of the 26 cases, 14 had normal amniotic fluid volume, five had oligohydramnios and seven had polyhydramnios. Fetuses with oligohydramnios had the highest incidence of concurrent fetal abnormalities; four of five fetuses (80%) with oligohydramnios had additional structural abnormalities. In the overall population, a very high incidence of other abnormalities was found; 17/26 (65%) cases showed additional abnormalities, some of which were not detected by ultrasound. Five fetuses had Meckel-Gruber syndrome and three had amniotic band syndrome. Only one of the 18 karyotypes obtained was abnormal (trisomy 18). Survival was very poor; only two of the eight who survived until birth are currently living.