Background: Tuberculous meningitis (TBM) is a highly devastating manifestation of tuberculosis. So far, the major role of the neuroradiology in the management of TBM has been restricted to diagnosis and follow-up of the complications. This study aimed to establish the use of advanced magnetic resonance imaging (MRI) techniques in the early detection of sequelae of TBM like vasculitis and hydrocephalous. Materials and Methods: In this prospective observational study, 30 patients of TBM were recruited during 1 year at a tertiary care health center of northern India and their serial MRI brain was done. Patients were between 18 and 45 years of age. Results: Basal/Sylvian exudates were seen in 90% of patients, hydrocephalus was found in 30% of patients and infarcts were found in 27% of patients. No significant difference was found between the mean, mean diffusivity (MD), and mean fractional anisotropy (FA) in frontal white matter, basal ganglia, thalamus, pons of cases and controls. A significant difference was seen between mean cerebral blood flow (CBF) in the region of basal ganglia of cases and controls (P < 0.05). No significant difference was seen between mean CBF in frontal white matter, thalamus of cases and controls. Diffusion tensor imaging parameters, MD, and FA were abnormal in the region of infarcts (basal ganglia) in three patients in the first scan, the parameters normalized in one patient (late subacute to chronic infarct in the first scan), and they remained abnormal in two patients. Conclusion: Advanced MRI techniques (magnetization transfer imaging) is helpful in visualizing hyperintense thickened meninges in basal cisterns and Sylvian fissures on pre-contrast imaging, and in identifying reduced CBF in the region of basal ganglia.
Trivedi R, Rathore RK, Gupta RK. Review: Clinical application of diffusion tensor imaging. Indian J Radiol Imaging 2008;18:45-52.