[MR image analysis of 147 cases of meningeal tuberculosis]

To investigate the MRI features of meningeal tuberculosis.

The MR images of meningeal tuberculosis were retrospectively analyzed in 147 patients who were clinically diagnosed from 2009 to 2014 years in our hospital, including 77 males, and 70 females. Their age ranged from 14 to 70 years, and the average age was(32 ± 13)years. All cases underwent MR plain scan and enhancement scan, and 26 cases underwent 3D TOF sequence and MRA vascular reconstruction. The characteristics of the morphological change, MR signal of meningeal lesions and the secondary changes were investigated for 56 cases of meningeal carcinomatosis due to lung cancer, including 29 males and 27 females. Their age ranged from 36 to 78 years old, and the average age was (58 ± 11)years. The MR imaging characteristics of meningeal lesions were compared with those of meningeal tuberculosis. Chi-square test and logistic regression analysis were used for count data analysis, and t-test was used for measurement data. P<0.05 was regarded as statistically significant.

Among 147 cases of meningeal tuberculosis, 146 (99.32%) had involvement of the cerebral pia mater, 104 of the basal cistern, and 108 of the cistern of lateral fissure pools. Lesions located in fissura longitudinalis cerebri pool, convexity of brain and cerebellar back were found in 46, 35 and 17 cases, respectively. MRI findings in plain scan were normal in 11 patients, and abnormal in 136 cases. Thickening meningeal lesions with different degrees were shown in the abnormal cases, with irregular or nodular slightly low signal intensity in T2WI in 77 cases. The meningeal lesions of all cases had homogeneous or inhomogeneous enhancement in enhanced scanning. There were 85 cases with meningeal nodules, including nodules with scattered distribution in 23 cases, and cluster distribution in 62 cases. The number of nodules was up to 1 105, including 452 nodules with homogeneous enhancement, and 653 nodules with ring enhancement. Most nodules of cluster distribution showed ring enhancement or separate enhancement. Secondary changes included hydrocephalus in 94 cases, anterior cerebral artery involvement in 17 cases, middle cerebral artery involvement in 58 cases, posterior cerebral artery involvement in 9 cases, 42 cases complicated with cerebral infarction and optic nerve involvement in 49 cases. Comparison of MR manifestations of meningeal tuberculosis and meningeal metastasis showed that, the location, type of meningeal involvement, edge of lesions, relative position of lesions and meninges, distribution of nodules were significantly different(P<0.05), except arachnoid lesions (P=0.066).

The MRI characteristics of meningeal tuberculosis were thickening of cerebral basilar cistern meninges. These signs were valuable for MRI diagnosis of meningeal tuberculosis, including cases complicated with meningeal nodules of cluster distribution. The nodules were of low signal on T2WI, with ring enhancement or separate enhancement, with secondary hydrocephalus, cerebral vasculitis in anterior circulation, and brain infarction. The result also showed that contrast-enhanced MRI was valuable for diagnosis of meningeal tuberculosis as well.