Three-Dimensional Super-Resolution Motion-Corrected MRI of the Fetal Posterior Fossa

OBJECTIVE: To validate a novel technique, 3D Super-Resolution Motion-Corrected MRI, for analyzing the fetal posterior fossa (PF). We hypothesized that linear measurements of key structures in the PF are concordant in 2D conventional and 3D reconstructed images. We further hypothesized that 3D reconstructions are more reliable when the transcerebellar diameter is measured in orthogonal planes.BACKGROUND: Current diagnosis of PF anomalies by conventional MRI is limited by fetal position, motion, and by 2D, rather than 3D representation. Diagnoses of fetal PF anomalies are thus primarily qualitative and subject to inter-expert variations in opinion. Additionally, the long diameter of the fetal cerebellum should measure the same if assessed in either axial or coronal planes, but this is often not the case in conventional fetal MRI. This has led to difficulties in standardizing certain fetal measurements on prenatal imaging.DESIGN/METHODS: From a database of pregnant women who received fetal MRIs at our institution, images of 49 fetal brains between 19-38 weeks gestation were reconstructed. Six PF structures were measured on 2D conventional and 3D reconstructed images, and agreement between methods was determined using concordance correlation coefficients (CCC). Agreement between orthogonal measurements of the transcerebellar diameter was also compared between the two methods using CCC.RESULTS: The CCC of each measurement was high (pu003c0.001) for all structures measured in both 2D conventional and 3D reconstructed images. Between axial and coronal measurements of the transcerebellar diameter, 3D reconstructed images outperformed 2D conventional images (pu003c0.001).CONCLUSIONS: This study validates 3D Super-Resolution Motion-Corrected MRI for imaging the fetal PF. Measurements of the transcerebellar diameter within a 3D reconstruction are more concordant between imaging planes, as they correct for fetal motion and orthogonal slice acquisition. This technique will facilitate further study of early fetal abnormalities of the PF.Study Supported by: NIH R25-3R25NS070682, R01-EB013248, and R01-EB018988. Disclosure: Dr. Pier has nothing to disclose. Dr. Gholipour has nothing to disclose. Dr. Afacan has nothing to disclose. Dr. Velasco-Annis has nothing to disclose. Dr. Clancy has nothing to disclose. Dr. Kapur has nothing to disclose. Dr. Estroff has nothing to disclose. Dr. Warfield has nothing to disclose.