Early cerebral lesions in cytomegalovirus infection: prenatal MR imaging.

PURPOSE: To assess the diagnostic and prognostic value of fetal cerebral magnetic resonance (MR) imaging of congenital cytomegalovirus (CMV) infection in comparison with that of level II ultrasonography (US).

MATERIALS AND METHODS: Institutional review board approval and informed consent for fetal MR imaging and data collection were obtained. Thirty-eight fetuses with CMV infection, examined by using serial level II US, underwent fetal MR imaging (mean gestational age, 25 weeks; age range at first fetal MR examination, 20-34 weeks). The frequency of pathologic findings at US (29 cases with transabdominal examination and nine cases with both transabdominal and transvaginal examination) and MR imaging was calculated, and a comparison between techniques by considering number (paired Student t test) and type (McNemar test) of finding was made. A comparison (paired Student t test) in cases of repeated fetal (nine of 38) and/or postnatal (14 of 38) MR imaging was obtained. Diagnostic and prognostic sensitivity was calculated for both techniques.

RESULTS: US and MR imaging findings were both normal in 47% of cases (18 of 38). Abnormal studies were reported in 26% (10 of 38) of US and 53% (20 of 38) of MR imaging cases. In 47% of cases (18 of 38), MR imaging provided additional information (P = .0002). MR imaging had better results than US in detecting polar temporal lesions (P = .0001), microencephaly (P = .03), and cortical anomalies (P = .06). In 44.5% of cases (four of nine), the second fetal MR examination results showed new findings (P = .05). In 79% of cases, postnatal MR imaging results confirmed prenatal findings (P = .08). MR imaging had higher sensitivity than US in detecting brain anomalies (92% vs 38%) and in predicting symptomatic infection (83% vs 33%). US and MR imaging revealed low positive predictive values (29% vs 36%).

CONCLUSION: Fetal MR imaging results can show abnormalities in the fetal brain after CMV infection, even when US results are normal. The early detection of some brain abnormalities, such as microencephaly and cortical anomalies, may substantially influence the prognosis of fetal infection.