Diagnostic Accuracy of Contrast-Enhanced FLAIR Magnetic Resonance Imaging in Diagnosis of Meningitis Correlated with CSF Analysis

Abstract

Purpose. To determine the diagnostic accuracy of contrast enhanced FLAIR sequence of MRI brain in the diagnosis of meningitis. Subjects and Methods. A prospective study of 57 patients with signs and symptoms of meningitis, referred to the radiology department for MRI examination. Out of these, there were 30 males and 27 females. They underwent MRI brain with contrast including postcontrast T1W and FLAIR sequences. Cerebrospinal fluid (CSF) analysis obtained by lumbar puncture after MRI was considered the “reference standard” against which MRI findings were compared. Results. Of 57 patients, 50 were diagnosed as having meningitis on subsequent CSF analysis. Out of these 50, 49 were positive on postcontrast FLAIR images and 34 were positive on postcontrast T1W images. One patient was labeled false positive as CSF analysis showed malignant cells (leptomeningeal carcinomatosis). In the diagnosis of meningitis, the sensitivity of postcontrast FLAIR sequence was 96% and specificity 85.71%, whereas the sensitivity of postcontrast T1W sequence was 68% and specificity 85.71%. Conclusion. Contrast-enhanced FLAIR sequence is more sensitive and specific than contrast-enhanced T1W sequence in the diagnosis of meningitis. It should be routinely used in suspected cases of meningitis.