Ultrasound in Obstetrics & Gynecology / Threedimensional reconstruction of defects in congenital diaphragmatic hernia: a fetal MRI study

Objective To assess the clinical feasibility and validity of fetal magnetic resonance imaging (MRI)based threedimensional (3D) reconstruction to locate, classify and quantify diaphragmatic defects in congenital diaphragmatic hernia (CDH). Methods This retrospective study included 46 cases of CDH which underwent a total of 69 fetal MRI scans (65 invivo and four postmortem) at the Medical University of Vienna during the period 1 January 2002 to 1 January 2017. Scans were performed between 16 and 38 gestational weeks using steadystate free precession, T2weighted and T1weighted sequences. MRI data were retrieved from the hospital database and manual segmentation of the diaphragm was performed with the opensource software, ITKSNAP. The resulting 3D models of the fetal diaphragm and its defect(s) were validated by postmortem MRI segmentation and/or comparison of 3D modelbased classification of the defect with a reference classification based on autopsy and/or surgery reports. Surface areas of the intact diaphragm and of the defect were measured and used to calculate defectdiaphragmatic ratios (DDR). The need for prosthetic patch repair and, in cases with repeated invivo fetal MRI scans, diaphragm growth dynamics, were analyzed based on DDR. Results Fetal MRIbased manual segmentation of the diaphragm in CDH was feasible for all 65 (100%) of the invivo fetal MRI scans. Based on the 3D diaphragmatic models, one bilateral and 45 unilateral defects (n = 47) were further classified as posterolateral (23/47, 48.9%), lateral (7/47, 14.9%) or hemidiaphragmatic (17/47, 36.2%) defects, and none (0%) was classified as anterolateral. This classification of defect location was correct in all 37 (100%) of the cases in which this information could be verified. Nineteen cases had a followup fetal MRI scan; in five (26.3%) of these, the initial CDH classification was altered by the results of the second scan. Thirtythree fetuses underwent postnatal diaphragmatic surgical repair; 20 fetuses (all of those with DDR 54 and 88% of those with DDR > 30) received a diaphragmatic patch, while the other 13 underwent primary surgical repair. Individual DDRs at initial and at followup invivo fetal MRI correlated significantly (P < 0.001). Conclusions MRIbased 3D reconstruction of the fetal diaphragm in CDH has been validated to visualize, locate, classify and quantify the defect. Planning of postnatal surgery may be optimized by MRIbased prediction of the necessity for patch placement and the ability to personalize patch design based on 3Dprintable templates. © 2019 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.(VLID)489250