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

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. 1. Introduction Meningitis continues to be an important disease throughout the world and can be a life-threatening emergency if not suspected, appropriately diagnosed, and managed expeditiously [1]. Meningitis prevails to be one of the most serious causes of hospital admission in Pakistan in all age groups [2]. Estimated prevalence of meningitis in our region is 1.57% [3]. Delay in administration of antibiotics is associated with death in adults suffering from acute bacterial meningitis. A delay of 4–6 hours in the administration of antibiotics after presentation independently conferred an 8.4-fold greater risk of death from meningitis [4]. Infective meningitis including tuberculous and bacterial meningitis is the leading cause of stroke in young patients in our country [5]. Bacterial meningitis is the major cause of morbidity in children below the age of 5 years [6]. The diagnosis of meningitis is established by history, physical examination, and laboratory evaluation but the ability to detect and differentiate intracranial infections has markedly improved with the introduction of MRI. The lack of bone artifacts and the multiplanar capability of MRI have led to this preeminence [7]. Computed tomography and magnetic resonance imaging play important roles in diagnosing brain infections but