OBJECTIVE: Dynamic contrast-enhanced MRI was used to investigate space-occupying lesions of the brain in 22 AIDS patients without prior neurologic disease. Final diagnoses were toxoplasmosis in 13 patients (19 lesions), primary lymphoma in 7 patients (9 lesions), and both diseases in two (2 lesions, respectively). MATERIALS AND METHODS: Dynamic contrast-enhanced MRI was done by using a heavily T1-weighted GE sequence (TR/TE 100/5, 80 degrees flip angle) performed before and repeatedly for a period of 15 min after intravenous bolus injection of Gd-DOTA (0.1 mmol/kg). Signal enhancement of the lesions and normal brain was measured as the difference of signal intensity before and after intravenous administration of contrast medium. RESULTS: Lymphomas displayed significantly greater enhancement (mean 67%; SD 18%) than toxoplasmosis did (mean 34%; SD 16%; p < 0.001) on FLASH images. The enhancement ratios of the two lesions were significantly (p < 0.01) different between 30 and 600 s after injection. The difference between toxoplasmosis (mean 49%; SD 17%) and lymphoma (mean 69%; SD 26%) enhancement ratios on delayed SE images was less significant (p = 0.04). CONCLUSION: Preliminary evidence suggests that dynamic sequences increase the specificity of MR in distinguishing between toxoplasmosis and lymphoma, and this has important clinical implications.
OBJECTIVE: Dynamic contrast-enhanced MRI was used to investigate space-occupying lesions of the brain in 22 AIDSpatients without prior neurologic disease. Final diagnoses were toxoplasmosis in 13 patients (19 lesions), primary lymphoma in 7 patients (9 lesions), and both diseases in two (2 lesions, respectively). MATERIALS AND METHODS: Dynamic contrast-enhanced MRI was done by using a heavily T1-weighted GE sequence (TR/TE 100/5, 80 degrees flip angle) performed before and repeatedly for a period of 15 min after intravenous bolus injection of Gd-DOTA (0.1 mmol/kg). Signal enhancement of the lesions and normal brain was measured as the difference of signal intensity before and after intravenous administration of contrast medium. RESULTS:Lymphomas displayed significantly greater enhancement (mean 67%; SD 18%) than toxoplasmosis did (mean 34%; SD 16%; p < 0.001) on FLASH images. The enhancement ratios of the two lesions were significantly (p < 0.01) different between 30 and 600 s after injection. The difference between toxoplasmosis (mean 49%; SD 17%) and lymphoma (mean 69%; SD 26%) enhancement ratios on delayed SE images was less significant (p = 0.04). CONCLUSION: Preliminary evidence suggests that dynamic sequences increase the specificity of MR in distinguishing between toxoplasmosis and lymphoma, and this has important clinical implications.
Authors: Mo Yang; James Sun; Harrison X Bai; Yongguang Tao; Xiangqi Tang; Lisa J States; Zishu Zhang; Jianhua Zhou; Michael D Farwell; Paul Zhang; Bo Xiao; Li Yang Journal: Medicine (Baltimore) Date: 2017-05 Impact factor: 1.889