Abstract: Objective To study the clinical diagnostic values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in brain AIDS-associated infection patients.Methods 32 subjects who had been confirmed with AIDS (17brain tuberculosis, 15 toxoplasmosis) were recruited to perfprm routine MRI, T1WI-CE and DTI sequences. Then lesions' morphological characteristics were observed, ADC and FA values of the lesions solid area, edematous area and the contralateral normal area were measured and results were statistically annlyzed. The diagnosis efficiency of the two values were analyzed by ROC curve.Result sSignificant differences of ADC and FA values were observed among the three regions between subjects with brain tuberculosis and subjects with toxoplasmosis (P<0.05). Compared with the contralateral normal areas, ADC and FA values of the solid area and edematous area in two groups had statistical significance (P<0.05). Both the FA values of solid and edematous area of the lesions in two groups and ADC values of solid and edematous area of tuberculosis had significant differences. FA values of the solid area in two groups had statistical significance(t=-5.637,P<0.01). ROC curve showed the AUC of ADC value was larger than that of FA value(0.721vs.0.919,respectively, P<0.05).Conclusion DTI is valuable for making diagnosis and differential diagnosis of AIDS patients with brain tuberculosis or toxoplasmosis, also providing the rational use of drug for clinical doctors' reference.

Key words: Toxoplasma gondii, Tuberculosis, Acquired immunodeficiency syndrome, FA value, ADC value