Objective: To determine the diagnostic accuracy of virtual autopsy using whole-body postmortem ultra-high field magnetic resonance imaging (MRI) at 7 Tesla (T), using a short T2-weighted imaging (T2-WI) protocol, compared with classical autopsy, for detecting structural abnormalities in small second-trimester fetuses.
Methods: Thirty consecutive fetuses at 13-19 weeks' gestation (weight, 17-364 g) were included following spontaneous pregnancy loss or termination of pregnancy. After fixation in 10% formaldehyde solution (48 h to 1 week), all fetuses were scanned using a two-dimensional turbo high-resolution T2-WI protocol with multislice relaxation time, followed by an invasive autopsy. The diagnostic accuracy of virtual autopsy vs classical autopsy was calculated for 990 anatomical structures (30 fetuses × 33 items). Sensitivity, specificity, positive and negative predictive values and Cohen's κ coefficient of agreement, with their 95% CIs, as well as the McNemar test, were used to evaluate the accuracy and agreement of the two diagnostic methods. Analysis was stratified by anatomical segment (nervous, pulmonary, cardiovascular, digestive, renal, facial and skeletal) and across three gestational-age intervals (13-14, 15-16 and 17-19 weeks).
Results: Considering classical autopsy as the gold standard, virtual autopsy had a sensitivity of 92.04% (95% CI, 85.42-96.29%) and a specificity of 97.87% (95% CI, 94.64-99.42%), with a positive predictive value of 96.30% (95% CI, 90.78-98.56%) and a negative predictive value of 95.34% (95% CI, 91.61-97.45%), achieving a diagnostic accuracy of 95.68% (95% CI, 92.73-97.68%) for detecting structural abnormalities in second-trimester fetuses. Cohen's κ for virtual vs classical autopsy was 0.907. The diagnostic ability of virtual autopsy at 7 T for malformed fetuses was superior to that of classical autopsy for analyzing the nervous system in small fetuses with pronounced autolysis, equivalent to that of classical autopsy when analyzing pulmonary, cardiovascular and renal systems and inferior when evaluating the fetal intestines. The sensitivity of virtual autopsy at 7 T for describing structural abnormalities increased with gestational age.
期刊介绍:
Ultrasound in Obstetrics & Gynecology (UOG) is the official journal of the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) and is considered the foremost international peer-reviewed journal in the field. It publishes cutting-edge research that is highly relevant to clinical practice, which includes guidelines, expert commentaries, consensus statements, original articles, and systematic reviews. UOG is widely recognized and included in prominent abstract and indexing databases such as Index Medicus and Current Contents.