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.

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.

Ossification of the fetal spine.

The neural arch ossification centers in the distal fetal spine were evaluated with ultrasound (US) during the second trimester of pregnancy in 239 fetuses. Ossification of the neural arch centers occurred in a predictable pattern and in a caudal direction. An additional vertebral level became ossified every 2-3 weeks from L-5 through S-5 after 16 weeks gestational age; by 22 weeks, S-2 was ossified in all fetuses studied. Radiographic and histologic correlation was performed in one fetus, and the method of establishing vertebral level with US proved accurate. In addition, the origin of the echoes at US corresponded to the histologic ossification centers. In 95% of the fetuses, S-1 was at the top of the iliac wing. Therefore, the level of ossification in the distal fetal spine could be rapidly assessed. Ossification to S-2 by 22 weeks, with a normal transverse configuration, normal overlying integument, and normal cranial structures, should lead to reassurance in excluding neural tube defects, except for distal sacral lesions.