Cytomegalovirus

KEY FACTS

Imaging

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Fetal growth restriction
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Brain findings
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  Microcephaly (up to 27%)
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  Ventriculomegaly (moderate to severe in 45%)
  - –
    
    Intraventricular adhesions, abnormal periventricular echogenicity
  - –
    
    Periventricular/parenchymal calcifications (often nonshadowing)
  - –
    
    Uni-/bilateral curvilinear echogenic streaks within basal ganglia, thalami indicate lenticulostriate vessel calcification
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  Intraparenchymal cysts: Periventricular, anterior temporal, occipital, frontoparietal
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  Cortical dysplasia
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  Cerebellar/cisterna magna abnormalities (cerebellar volume loss in 67% of infants with congenital infection)
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Hepatosplenomegaly secondary to extramedullary hematopoiesis
•

Echogenic bowel
•

Cardiomyopathy ± hydrops

Top Differential Diagnoses

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Toxoplasmosis: Final diagnosis made on maternal serology as imaging findings are similar

Scanning Tips

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Always check middle cerebral artery velocity in hydropic fetus
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  Anemia maybe be cause: Alloimmune or due to bone marrow suppression in infection
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If cephalic presentation, use transvaginal ultrasound for highest resolution brain images
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Do not overcall echogenic bowel : Very technique-dependent observation
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  Use V4 transducer, turn off harmonics, turn down gain and see if bowel still visible as bone disappears
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  Bowel must be as bright as bone to call abnormal

This fetus with hepatosplenomegaly from CMV infection shows a large liver

, but what is most striking is the dramatic enlargement of the spleen

. The enlargement is caused by extramedullary hematopoiesis secondary to fetal anemia.

Ultrasound at 27 weeks in a fetus with CMV infection shows new-onset ascites

without other evidence of hydrops and mildly enlarged liver

. The bowel is also diffusely echogenic

. Intrauterine demise occurred shortly after the development of ascites.

Axial ultrasound through the fetal abdomen shows focal echogenic bowel

, which is as bright as the bone in the adjacent spine

Axial graphic shows periventricular

and basal ganglia

calcifications, regions of cortical dysplasia

and ventricular dilation due to adjacent white matter volume loss. The yellowish white matter abnormalities reflect regions of edema, demyelination, &/or gliosis.