Decoding CNS granulomas: cracking the imaging mystery in tuberculosis and neurocysticercosis endemic zones

Background Central nervous system (CNS) granulomas present formidable diagnostic challenges in tuberculosis and neurocysticercosis-endemic regions, where empirical therapy based on imaging alone frequently results in misclassification and suboptimal outcomes. Objective To evaluate the diagnostic accuracy of conventional and multiparametric MRI in differentiating CNS granulomas, correlate imaging findings with histopathological diagnoses, and assess 3-6 month clinical and radiological outcomes in a prospectively enrolled cohort. Methods We conducted a prospective observational study (February 2016-August 2017) of 30 consecutive patients with MRI-diagnosed CNS granulomas at a tertiary referral center. Comprehensive clinical assessment, multisequence MRI including diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC) mapping, and selective MR spectroscopy were performed. Stereotactic biopsy was undertaken for lesions demonstrating treatment failure or accessible progression. Primary endpoints included imaging-histopathology concordance and clinical/radiological response at 3-6 months. Results The cohort comprised 22 females and 8 males (mean age 24.8 years, range 11-56). Presenting features included headache (96.7%) and seizures (86.7%). Baseline MRI demonstrated lesions Conclusions Conventional MRI features of CNS granulomas demonstrate substantial overlap across etiologies, with significant potential for misdiagnosis in endemic settings. Multiparametric imaging enhances diagnostic confidence but cannot eliminate misclassification. Early tissue diagnosis of treatment-resistant or progressing lesions frequently alters management and is essential for optimal patient outcomes. These findings support a combined approach incorporating advanced imaging, serial clinical assessment, and timely biopsy when clinically indicated.