Specific Imaging Findings

The most common imaging finding of congenital cytomegalovirus (CMV) infection is intracranial calcifications (in 33–70% of patients), which are typically periventricular thick and chunky, while faint and punctate in other locations. Absence of calcifications does not exclude congenital CMV infection. While calcifications are best seen on CT, MRI is the modality of choice for all other lesions. Neuronal migration abnormalities (in up to 10%) range from lissencephaly to diffuse or focal polymicrogyria. White matter abnormalities (up to 22%) are of low CT attenuation and T1 signal (and high T2 signal over 8–10 months of age), and abnormal anterior temporal white matter, primarily vacuolization and cyst formation, is characteristic. Ventriculomegaly is common (in 10–45%), with or without microcephaly and cerebellar hypoplasia. The most specific findings in children with neurodevelopmental delay are cortical malformations, white matter abnormalities, cerebellar hypoplasia, and temporal lobe lesions. Multifocal predominantly deep parietal white matter lesions in patients with static encephalopathy are indicative of congenital CMV infection. In asymptomatic individuals a posterior-predominant pattern with preserved periventricular and subcortical white matter is characteristically found.

Pertinent Clinical Information

Congenital CMV infection is the most common intrauterine infection, occurring in 0.15–2.0% of all live births. Confirmatory tests are polymerase chain reaction (PCR) in amniotic fluid and virus isolation from urine in the first weeks of life. Neonatal signs of infection include jaundice, hepatosplenomegaly, petechiae, microcephaly, and chorioretinitis. About 90% of affected infants are, however, asymptomatic at birth, and only 10–15% of these will develop persistent problems, primarily sensorineural hearing loss, mental retardation, cerebral palsy, and seizures.