Diagnostic Accuracy of MRI for Detection of Meningitis in Infants

PURPOSE:To determine the accuracy of MR imaging for diagnosis of meningitis in infants.MATERIALS AND METHODS:Retrospective review of infants less than 1 year of age who underwent a brain MR imaging for meningitis from 2010-2018. Gold standard for diagnosis of bacterial meningitis was a positive bacterial CSF culture or a positive blood culture with an elevated CSF WBC count, and diagnosis of viral meningitis was a positive CSF PCR result and elevated CSF WBC count. Sensitivity, specificity, PPV, NPV, and accuracy for MR imaging diagnosis of meningitis were calculated.RESULTS:Two hundred nine infants with mean age 80 days (range 0-347 days) were included. There were 178 true positives with the most common pathogens being: Group B Streptococcus (58), E. coli (50), Streptococcus pneumoniae (21), H. influenzae (4); Herpes simplex virus 1 or 2 (18); Enterovirus (4); and other (23). There were 31 true negatives. Range of sensitivity, specificity, PPV, NPV, and accuracy of MR imaging for detection of meningitis was 67.4-83.5%, 92.3-95.7%, 95.0-98.6%, 33.3-76.5%, and 71.3-86.5% respectively. MR imaging sensitivity decreased after 10 days from time of presentation while specificity remained stable. Among individual MR imaging findings, leptomeningeal enhancement was the most sensitive finding, while cerebritis, infarction, ventriculitis, abscess, and intraventricular purulent material were the most specific findings.CONCLUSIONS:MR imaging of the brain demonstrates high specificity and moderate sensitivity for diagnosis among infants presenting with signs and symptoms of meningitis. The results reflect current standard of care for imaging of infants with meningitis however a selection bias for imaging of more severe meningitis may affect these results.