Contrasting MRI patterns in early infant human parechovirus CNS infection: a brief report

Abstract Human parechovirus (HPeV), particularly genotype A3, is a recognized cause of sepsis-like illness and central nervous system (CNS) infection in neonates and young infants. Brain magnetic resonance imaging (MRI) plays a key role in identifying CNS involvement, although neuroradiological findings may be heterogeneous. We report two infants with PCR-confirmed HPeV CNS infection presenting at 10 and 40 days of life, respectively, with contrasting MRI patterns. The first neonate showed the typical phenotype of bilateral fronto-parietal and periventricular white matter diffusion restriction despite minimal cerebrospinal fluid (CSF) pleocytosis. The second infant demonstrated isolated diffuse leptomeningeal enhancement without parenchymal lesions. Both patients experienced rapid clinical recovery and remained seizure-free; neurodevelopment was normal at follow-up in the case with white matter involvement. These observations highlight the spectrum of MRI findings in early infant HPeV CNS infection and reinforce that normal or near-normal CSF parameters do not exclude significant CNS involvement. Early MRI, combined with molecular testing, may improve diagnostic accuracy and inform follow-up strategies. Conclusion : These observations highlight the spectrum of MRI findings in early infant HPeV CNS infection and reinforce that normal or near-normal CSF parameters do not exclude significant CNS involvement. Early MRI, combined with molecular testing, may improve diagnostic accuracy and inform follow up strategies. What is Known: • Human parechovirus (HPeV) CNS infection in young infants is commonly associated with white-matter diffusion abnormalities on MRI and minimal or absent CSF pleocytosis . • MRI is a key diagnostic tool in identifying CNS involvement, although neuroradiological findings may be heterogeneous . What is New: • This report describes two infants with HPeV CNS infection showing contrasting MRI patterns, including isolated leptomeningeal enhancement without parenchymal lesions . • These findings broaden the recognized neuroradiological spectrum of HPeV infection and highlight the diagnostic value of MRI even in clinically mild cases .