Abstract:

Objective To summarize the MR imaging characteristics of tuberculous meningitis (abbr. “TBM”)and toxoplasmosis encephalopathy(abbr. “TE”) in HIV infected individuals with different CD4 ⁺ T cell levels. Methods From January 2008 to January 2018, 46 patients with central nervous system infection were selected among HIV-infected patients admitted to Beijing Ditan Hospital, Capital Medical University. Among them, 21 cases were TE patients with a total of 89 lesions (TE group), 25 cases were TBM patients with a total of 174 lesions (TBM group). Differences in MR images between CD4 ⁺ T cells less than 15 and more than 15 cells/μl were evaluated, inclding lesion distribution, morphology, size, DWI and ADC characteristics, and degree of peripheral edema. Results The proportion of lesions in cortex and subcortex among all lesions within TE group and TBM group were: CD4 ⁺ T cells less than 15 cells/μl, 83.0% (44/53) and 45.8% (33/72), with statistically significant difference (χ ²=24.203, P=0.000); CD4 ⁺ T cells more than 15 cells/μl, 77.8% (28/36) and 59.8% (61/102), with no statistically difference (χ ²=5.076, P=0.079). When CD4 ⁺ T cells were less than 15 cells/μl, the proportion of nodular lesions among all lesions within TE group and TBM group were 54.7% (29/53) and 75.0% (54/72) respectively, with statistically significant difference between the two groups (χ ²=5.629, P=0.018). When CD4 ⁺ T cells were more than 15 cells/μl, the proportions of plaque-shaped circular lesions in those two groups were 88.9% (32/36) and 64.7% (66/102) respectively, with statistically significant difference between the two groups(χ ²=7.560, P=0.006). When CD4 ⁺ T cells were more than 15 cells/μl, the proportion of lesions with low and high DWI signal were 41.6% (15/36), 27.8% (10/36) within TE group, and 7.8% (8/102), 41.2% (42/102) within TBM group,difference of low, middle and high DWI signal proportion between TE and TBM group was statistically significant(χ ²=21.964, P=0.000). Additionally, proportion of lesions with low and high DWI signal were 22.2% (8/36), 41.7% (15/36) within TE group, and 40.2% (41/102), 9.8% (10/102) within TBM group, differences were statistically significant too(χ ²=18.440, P=0.000). Conclusion The MR images of TBM and TE patients in HIV infected individuals with different CD4 ⁺ T cell count levels are different in lesion distribution, morphology, DWI and ADC signal characteristics.

Key words: HIV infections, Tuberculosis, meningeal, Toxoplasmosis, cerebral, Magnetic resonance imaging, Comparative study