Supplementary Material for: Real-Time Volume Contrast Imaging in the A Plane with a Four-Dimensional Electronic Probe Facilitates the Evaluation of Fetal Extremities in Midtrimester Sonograms

<i>Objective:</i> To evaluate the efficiency of real-time volume contrast imaging in the A plane (VCI-A) of fetal extremities, compared with conventional two-dimensional ultrasound (2D). <i>Methods:</i> This was a randomized controlled trial of 100 patients undergoing midtrimester sonography. The fetal limbs were imaged with either 2D or VCI-A with a four-dimensional (4D) electronic probe. Time required for the examination, number of images stored, and quality of the documentation were compared. During the study, 6 fetuses with abnormal extremities were scanned with both 2D and VCI-A, and the diagnostic accuracy and quality of the images were also compared. <i>Results:</i> In the VCI-A group, the fetal extremities were imaged more rapidly (2.3 ± 1.1 vs. 3.3 ± 0.9 min, <i>p</i> < 0.0001), less images were required to document the examination (5.6 ± 1.4 vs. 7.3 ± 1.6), and an optimal documentation was more frequently obtained (84 vs. 54%, <i>p</i> < 0.0001) compared with the 2D group. In malformed fetuses, a precise diagnosis was achieved with both techniques, although images obtained with VCI-A were found to be of superior quality. <i>Conclusions:</i> Real-time VCI-A with a 4D electronic probe is an effective tool for imaging the fetal extremities in midtrimester examinations and carries some advantages over conventional 2D sonography.