Magnetization Transfer MR Imaging in CNS Tuberculosis

meningitis on MR images. The purpose of this study was to improve the characterization of lesions in CNS tuberculosis and to assess the disease load using magnetization transfer (MT) imaging. METHODS: A total of 107 tuberculomas in seven patients with or without meningitis and 15 patients with tuberculosis meningitis alone were studied. Fifteen patients with cysticercus granulomas with T2 hypointensity, five patients each with viral and pyogenic meningitis, and two patients with cryptococcal meningitis were also studied. The MT ratios were calculated from tuberculomas, cysticercus granulomas, and thickened meninges in tuberculous, viral, pyo-genic, and cryptococcal meningitis and were compared within each pathologic group and with the MT ratio of different regions of normal brain parenchyma. Detectability of lesions on T1-weighted MT spin-echo (SE) images was compared with that on conventional SE and postcon-trast MT-SE images. RESULTS: Thickened meninges appeared hyperintense relative to surrounding brain paren-chyma in the basal and supratentorial cisterns on precontrast MT-SE images in all 18 patients with tuberculosis meningitis. These meninges were not seen or were barely visible on conven