Objective To investigate the diagnostic value of brain magnetic resonance imaging in detecting central nervous system diseases among AIDS patients of different levels of T cells. Methods Total of 164 AIDS patients who did not receive antiviral treatment were divided into 2 groups according to their baseline CD4+ T cell counts. Group A had CD4+ T cell below or equal to 50 cells/μl(n = 81) and group B had CD4+ T cells over 50 cells/μl(n = 83). All patients underwent brain MRI scan. Imaging analysis and the prevalence of the central nervous system disorders were compared between two groups. Results Among them 48 cases were found of abnormal brain MRI, group A was higher than group B(35.8% vs. 22.9%) although without statistical significance(P = 0.065). Altogether 48 cases were diagnosed as AIDS related central nervous system disorders based on clinical symptoms, signs and laboratory findings. The prevalence of CNS disorders was higher in group A than in group B(41.9% vs. 16.8%) with statistical significance(P < 0.01). Conclusions The patients with CD4+ T cell count less than or equal to 50 cells/μl had high prevalence of CNS diseases. Brain MRI plays an important role in the diagnosis and differentiation of CNS diseases in advanced AIDS patients. This study suggests patients with low CD4+ T cell count(≤ 50/μl) should routinely undergo MRI examination. Objective To investigate the diagnostic value of brain magnetic resonance imaging in detecting central nervous system diseases among AIDS patients of different levels of T cells. Methods Total of 164 AIDS patients who did not receive antiviral treatment were divided into 2 groups according to their baseline CD4 + T Cell counts. Group A had CD4 + T cell below or equal to 50 cells / μl (n = 81) and group B had CD4 + T cells over 50 cells / μl the prevalence of the central nervous system disorders were compared between two groups. Results Among the 48 cases were found of abnormal brain MRI, group A was higher than group B (35.8% vs. 22.9%) although without statistical significance (P = 0.065) The prevalence of CNS disorders was higher in group A than in group B (41.9% vs. 16.8%) with sta Conclusions The patients with CD4 + T cell count less than or equal to 50 cells / μl had high prevalence of CNS diseases. Brain MRI plays an important role in the diagnosis and differentiation of CNS diseases in advanced AIDS patients This study suggests patients with low CD4 + T cell count (≤ 50 / μl) should routinely undergo MRI examination.