Potential Clinical Benefits and Limitation of Foetal Virtuopsy Using a High-Field MRI of 7 Tesla to Assess First Trimester Foetuses Versus Stereomicroscopic Autopsy

Abstract

Background: Performing accurate autopsies on small foetuses is a difficult process to achieve, especially when a certain degree of autolysis is involved. High-field MRI of 7 T has proven to be a useful tool to describe small foetuses anatomy, therefore the purpose of our study was to establish its diagnostic usefulness assessing first trimester foetuses compared to stereomicroscopic autopsy or microscopic evaluation. Methods Nine consecutive cases of first trimester foetuses were divided in two groups according to gestational age and crown-rump length (Embryo Group cases of 9-10 gestational weeks and Foetal Group cases of 13 gestational weeks) and scanned using a 3D Fast Imaging with Steady Procession 3D (FISP 3D) respectively 2D Turbo High Resolution T2 WI protocol. Images were interpreted by a radiologist, and two embryologists. All cases were submitted to invasive autopsy, blinded to the imagistic results. Findings Virtuopsy brought important additional information in all cases from the Embryo Group and had similar diagnostic capacity as the conventional method in evaluating the cases from the Foetal Group. The Cohen's kappa coefficient of agreement was k=0.92 (95% CI 82-97), highlighting a very good concordance between foetal virtuopsy and stereomicroscopic autopsy, also supported by the McNemar test p =1.00. The imagistic method presented a better capacity in visualising embryonic structure especially embryonic brain with lesser method disadvantages (p=0,005.) and similar capacity for visualising foetal structures in the second group. Interpretation Virtual autopsy using high field MRI at 7T is emerging as a promising alternative approach to stereomicroscopic autopsy in the assessment of malformed first trimester human foetuses. Funding: Not applicable. Declaration of Interest: The authors report no declarations of interest. Ethical Approval: The study protocol was approved by the “Iuliu Hatieganu” University of Medicine and Pharmacy Ethics Committee and written informed parental consent was obtained before the imagistic and conventional autopsy procedures.