MRI Findings of Miliary Tuberculosis of the Brain

ABSTRACT

PURPOSE: To evaluate MRI(Magnetic Resonance Imaging) findings of miliary tuberculosis of the brain. MATERIALS AND METHODS: Six patients with miliary tuberculosis of the brain diagnosed by characteristic clinical or laboratory findings were studied with spin echo MRI before and after contrast enhancement. We retrospectively evaluated MRI findings acording to the appearance, distribution, location, and enhancement pattern of the granulomas as well as associated other abnormalities. RESULTS: In six patients, contrast-enhanced MRI of thebrain showed numerous punctate, contrast enhancing lesions scattered throughout the brain. Unenhanced MRI failed to demonstrate small granulomas except a few small foci of high signal intensity on T2-weighted images. The shapes of enhancing granulomas were homogeneous nodular enhancement in 86% of cases and small ring enhancement in 14%.98% of granulomas were smaller than 3-mm and 2% were larger. Although several lesions were located in the basalganglia, thalamus, and brain stem, the majority were located in the subpial and subarachnoid space. There was no significant difference in distribution of granulomas between the supratentorial and the infratentorial areas. Other associated abnormalities were focal meningitis in five cases and focal cerebritis in one. On chest radiograph, all patients had miliary tuberculosis in the lungs. CONCLUSION: Contrast-enhanced T1-weighted MRimaging showed numerous round, very small enhancing lesions scattered throughout the brain. The majority of lesions were located in the subpial and subarachnoid space. Contrast-enhanced T1-weighted images are helpful inthe detection and diagnosis of miliary disseminated tuberculous granulomas and meningitis.