Cranial ultrasound and MRI: complementary or not in the diagnostic assessment of children with congenital CMV infection?

Whether or not cranial ultrasound (crUS) and cerebral magnetic resonance imaging (MRI) have both a place in the assessment of children with congenital cytomegalovirus infection (cCMV) remains a topic of discussion between research groups. Literature suggests that MRI is indicated only in children with abnormal crUS. In Flanders, Belgium, combined crUS and MRI was performed on 639 children with cCMV, referred for diagnostic assessment. Cranial US was classified as abnormal in the presence of striatal vasculopathy, calcifications, cysts, cystic germinolysis, and/or ventriculomegaly. MRI findings were classified as abnormal in the presence of gyration disorders, cerebellar abnormalities, ventriculomegaly, cysts, or pathologic white matter lesions. One in five children (93/480) with normal crUS showed abnormal findings on MRI. Of them, 85 (91.4%) were classified as symptomatic. In 37 of those 93 children (39.8%), classification as severely symptomatic was made based on MRI lesions alone. MRI and crUS proved to be complementary in the assessment of CNS involvement in children with cCMV. Long-term studies are needed to evaluate the importance of this finding with respect to outcome and benefit of therapy in this particular subgroup of patients with cCMV infection. Conclusion : Our findings support an enhanced role of MRI in the diagnosis of CNS involvement in children with cCMV infection. The ideal assessment should include both imaging techniques, as the strengths of each test compensate for the other’s weaknesses. What is Known: • Congenital CMV infection involves the central nervous system with direct injury to and possible disruption of brain development. • Experts suggest that MRI is indicated only in children with abnormal crUS. What is New: • In almost 20% of our children with a normal cranial ultrasound, abnormalities were detected on MRI. • Our results suggest that performing both MRI and cranial US is important to obtain a complete assessment of central nervous system involvement in children with cCMV.