Background and Purpose: CMV (cytomegalovirus) is the most common prenatal infection in the developed world. Temporal lobes T2 hyperintensity was previously described in association with prenatal CMV infection. However, these findings are often perplexing with high inter-observer variability. Our objective was to evaluate the diagnostic value of temporal lobes T2 signal on fetal MRI in predicting prenatal CMV infection.
Materials and Methods: In this retrospective study, 51 fetuses with suspected CMV exposure were included. Gestational age ranged between 29 and 36 weeks. Following 3T fetal MRI, CMV infection status was confirmed or excluded by viral DNA amplification using polymerase chain reaction (PCR). Mean and maximal T2 temporal lobe hyperintensities were evaluated quantitatively by calculating T2 signal in the temporal lobes normalized to the signal of the surrounding amniotic fluid. Intra-observer and inter-observer variability as well as diagnostic performance were evaluated.
Results: Of our cohort, 29 fetuses were found to be positive for CMV infection on PCR analysis. Normalized temporal lobes T2 signal did not change with gestational age. There was no statistically significant difference in temporal lobes normalized mean and maximal T2 signal between CMV positive and CMV negative fetuses.
Conclusion: Although described in the literature as an associated imaging finding, increased T2 signal in the temporal lobes in fetal MRI is not a reliable sign of CMV infection in fetuses suspected for congenital CMV infection. Further studies are required, expanding the search for more sensitive imaging biomarkers of prenatal CMV infection.
