Malformations of Cortical Development: Diagnostic Accuracy of Fetal MR Imaging

Abstract

Purpose:To determine the diagnostic accuracy of fetal magnetic resonance (MR) imaging for malformations of cortical development by using postnatal MR imaging as reference standard. Materials and Methods:Eighty-one patients who had undergone fetal and postnatal MR imaging of the brain were identified in this institutional review board-approved, HIPAA-compliant study.Images were retrospectively reviewed in consensus by two pediatric neuroradiologists who were blinded to clinical information. Sensitivity and specificity were calculated according to retrospective review of the images and clinical reports for fetal MR images. The Fisher exact test was used to compare results for fetuses imaged before and after 24 gestational weeks and for image review versus clinical reports for fetal MR images. Results:Median gestational age at fetal MR imaging was 25.0 weeks (range, 19.71-38.14 weeks). Postnatal MR imaging depicted 13 cases of polymicrogyria, three cases of schizencephaly, and 15 cases of periventricular nodular heterotopia. Sensitivity and specificity of fetal MR imaging were 85% and 100%, respectively, for polymicrogyria; 100% each for schizencephaly; and 73% and 92%, respectively, for heterotopia. When heterotopia was seen in two planes, specificity was 100% and sensitivity was 67%. Sensitivity for heterotopia decreased to 44% for fetuses younger than 24 weeks. According to reports for fetal MR images, prospective sensitivity and specificity, respectively, were 85% and 99% for polymicrogyria, 100% and 99% for schizencephaly, and 40% and 91% for heterotopia. Conclusion:Fetal MR imaging had the highest sensitivity for polymicrogyria and schizencephaly. Specificity was 100% for all cortical malformations when the abnormality was seen in two planes. Sensitivity for heterotopia was lower for fetuses younger than 24 weeks. Knowledge of the gestational age is important, especially for counseling patients about heterotopia.q RSNA, 2012

Evaluation of Subependymal Gray Matter Heterotopias on Fetal MRI

“…3,14,15,20,21 However, very few describe the diagnostic accuracy. 17,22 The largest published series of 15 patients reported that fetal MR imaging was up to 73% sensitive and 100% specific for diagnosing SEH. 17 Our study examined a much larger cohort of patients, increasing the validity of our findings.…”

“…17,22 The largest published series of 15 patients reported that fetal MR imaging was up to 73% sensitive and 100% specific for diagnosing SEH. 17 Our study examined a much larger cohort of patients, increasing the validity of our findings. However, we focused on a specific population of patients, looking only at fetuses with prenatally diagnosed spinal dysraphisms; this type of search decreased the generalizability of our findings.…”

“…[13][14][15] Many authors believe that SEH can be identified on fetal MR imaging. 3,16,17 In 1 small series of 15 patients, fetal MR imaging was reported to be up to 100% specific, though only 67% sensitive, in detecting SEH. 17 To date, no large series have examined this finding on MR imaging in fetuses with spinal dysraphism.…”

“…3,16,17 In 1 small series of 15 patients, fetal MR imaging was reported to be up to 100% specific, though only 67% sensitive, in detecting SEH. 17 To date, no large series have examined this finding on MR imaging in fetuses with spinal dysraphism. The purpose of this study was to examine the accuracy of diagnosing SEH in fetuses with spinal dysraphism via fetal MR imaging.…”

Correlation of Prenatal and Postnatal MRI Findings in Schizencephaly

“…The largest published series are those of Oh et al (6 cases) 3 and Denis et al (3 cases). 17 Both of these studies were limited to subjects with open-lip schizencephaly (unilateral or bilateral), and the pregnancy was terminated in all 3 subjects in the study of Denis et al Recent work by Glenn et al 25 on a relatively large series of fetal MR imaging in subjects with malformations of cortical development included 3 subjects with schizencephaly. In their study, fetal MR imaging had 100% sensitivity and specificity for the prenatal diagnosis of schizencephaly in their 3 patients (both open and closed).…”