Stereoscopic evaluation of fetal bony structures.
OBJECTIVE
The purpose of this study was to assess the performance of stereoscopic compared with conventional viewing of 3-dimensional ultrasound (3DUS) data for evaluation of fetal bony structures.


METHODS
A series of 47 human fetuses were evaluated with conventional 3DUS scanning systems. Twenty-five volumes of the fetal head, thorax, and abdomen were acquired. Volume-rendered images of the fetal cranium and spine were displayed interactively on a real-time stereoscopic graphics workstation. Visualization parameters were interactively optimized. Both conventional and stereoscopic images were evaluated for the clarity of structure visualization (0, nonvisualized; 1, nondiagnostic; 2, adequate; and 3, excellent), the ability to identify key anatomic landmarks (eg, sutures, palate, vertebrae, and ribs), artifacts, and evaluation time.


RESULTS
Fetal bony structures, especially high-contrast structures, were readily identified with both conventional and stereoscopic. Overall, stereoscopic viewing provided a statistically significant improvement compared with conventional viewing (P < .01), improved conspicuity of complex bony structures, and added structural detail information that assisted in identification of complex anatomy in 14% of the fetal skull and 26% of the fetal spine cases. Overlapping structures were better identified on the volume-rendered stereoscopic display, with stereoscopic viewing improving differentiation of near and far structures. An interactive display and inclusion of a planar slice review further assisted in identification of structures. The evaluation times were comparable for the two methods.


CONCLUSIONS
The stereoscopic display of rendered 3DUS data adds valuable information that assists in identification of fetal bony structures, such as cranial sutures and spinal vertebrae, particularly in complex formations. The increasing availability of stereoscopic visualization workstations will offer an additional tool for fetal diagnosis and evaluation.
Nelson
Thomas R
TR
Department of Radiology, University of California San Diego, La Jolla, CA 92037-0610, USA. tnelson@ucsd.edu
Ji
Eun K
EK
Lee
Jong H
JH
Bailey
Michael J
MJ
Pretorius
Dolores H
DH
D001842:Bone and Bones / Q000000981:diagnostic imaging* / Q000196:embryology; D003867:Depth Perception; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D011247:Pregnancy; D016216:Ultrasonography, Prenatal / Q000379:methods*; D014584:User-Computer Interface