Virtual autopsy using 7T MRI vs classic fetal autopsy.xlsx

<b>Introduction:</b> Studies that analyses the diagnostic utility and clinic potential of whole-body fetal imaging using ultra-high magnetic are lacking. This study aimed to determine the diagnostic accuracy of virtual autopsy using ultra-high field magnetic resonance imaging at 7 T vs classic autopsy as the reference in the assessment of small second-trimester fetuses. Additionally, we tested a shorter T2‐weighted imaging protocol.<b>Material and methods:</b> Thirty consecutive fetuses (13–19 weeks of gestation, weighing 16–300 g) resulting from spontaneous and therapeutic terminations of pregnancy were considered. After fixation in 10% formalin solution (48 h to 1 week), all fetuses were scanned using a two‐dimensional turbo high-resolution multi-slice relaxation time T2‐weighted imaging protocol followed by an invasive autopsy. The diagnostic accuracy of virtual autopsy vs classic autopsy was calculated for 990 anatomic structures (30 fetuses × 33 items). Sensitivity, specificity, positive predictive value, negative predictive value, and Cohen’s k coefficient of agreement with their 95% confidence intervals, as well as the McNemar test, were used to define the agreement of the two diagnostic methods, overall, by anatomic segment (cerebral, pulmonary, cardiovascular, renal, facial, and skeletal), and across three gestational age intervals (13–14, 15–16, and 17–19 weeks).<b>Results</b>: Compared with classic autopsy, virtual autopsy had a sensitivity of 92.04% [95% confidence interval 85.42–96.29] and a specificity of 97.87% [94.64–99.42], with a positive predictive value of 96.30% [90.78–98.56] and a negative predictive value of 95.34% [91.61–97.45], achieving a diagnostic accuracy for detecting structural abnormalities in second-trimester fetuses of 95.68% [92.73–97.68]. Cohen’s k was 0.907. The diagnostic accuracy of the virtual autopsy at 7 T for malformed fetuses was superior for analyzing the cerebral system in small fetuses with pronounced autolysis; was equivalent to classic autopsy when analyzing pulmonary, cardiovascular, and renal systems; and was inferior for evaluating fetal intestines. The diagnostic sensitivity of virtual autopsy at 7 T for describing structural abnormalities increased with fetal gestational age.<b>Conclusions:</b> Virtual autopsy using magnetic resonance imaging at 7 T and a turbo high-resolution multi-slice relaxation time T2‐weighted imaging protocol is a feasible postmortem diagnostic tool to identify structural anomalies in fetuses.