Diagnostic Accuracy of Contrast-Enhanced FLAIR MRI in the Diagnosis of Meningitis, Keeping CSF Analysis as the Gold Standard

Abstract

Meningitis is a potentially life-threatening inflammation of the meninges that requires prompt diagnosis to reduce neurological complications and mortality. Cerebrospinal fluid (CSF) analysis remains the reference standard, but contrast-enhanced fluid-attenuated inversion recovery magnetic resonance imaging (CE-FLAIR MRI) may improve detection of meningeal enhancement and complement CSF assessment. Objective: To determine the diagnostic accuracy of CE-FLAIR MRI for meningitis using CSF analysis as the reference standard. Methods: This cross-sectional diagnostic accuracy study included 103 patients with suspected meningitis at MTI/Hayatabad Medical Complex, Peshawar, from May to November 2022. All participants underwent CE-FLAIR MRI and CSF analysis. Diagnostic performance was assessed using a 2 × 2 contingency table, and sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy were calculated with 95% confidence intervals. Results: Among 103 patients, 61 were CSF-positive, and 42 were CSF-negative. CE-FLAIR MRI identified 55 true-positive, 34 true-negative, 8 false-positive, and 6 false-negative cases. Sensitivity was 90.2% (95% CI: 80.2–95.4), specificity 81.0% (66.7–90.0), PPV 87.3% (76.9–93.4), NPV 85.0% (70.9–92.9), and overall accuracy 86.4% (78.5–91.7). CE-FLAIR MRI showed a strong association with CSF-confirmed meningitis (Cramer’s V = 0.717, p<0.001). Conclusions: CE-FLAIR MRI showed good diagnostic performance and may serve as a useful non-invasive adjunct to CSF analysis in suspected meningitis; however, it should not replace CSF assessment where lumbar puncture is feasible.