[en] Objective: To assess the diagnostic value of MSCT and MR perfusion in the differentiation of benign and malignant soft tissue tumors. Methods: Twenty-six patients with soft tissue tumors were studied in MSCT perfusion and 29 patients in MR perfusion. The differences of perfusion parameters of benign and malignant tumors were analyzed. Results: The average value of MSCT BF was (24.49 ± 14.49) ml·100 mg^-1 · min^-1 for malignant group, and (1.98 ± 1.19) ml·100 mg^-1 · min^-1 for benign group. PS was (14.64 ± 1.89) ml·100 mg^-1·min^-1 for malignant group, and (2.40 ± 0.38) ml·100 mg^-1·min^-1 for benign group. The mean BF and PS in benign and malignant tumors had significant difference in MSCT perfusion. The sensitivity , specificity, accuracy, positive predictive value, and negative predictive value of MSCT in estimating the potential malignancy of the tumors were 90.9%(10/11), 86.7%(13/15), 88.5%(23/26), 83.3%(10/12), and 92.9%(13/14), respectively. The average value of MR BF was (0.11 ± 0.02) ml·100 mg^-1·min^-1 for malignant group, and (0.07 ± 0.01) ml·100 mg^-1·min^-1 for benign group. The mean BF in benign and malignant tumors has significant difference in MR perfusion. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of MR in estimating the potential malignancy of the tumors were 91.7%(11/12), 88.2%(15/17), 89.7%(26/29), 84.6%(11/13), and 93.8%(15/16), respectively. Conclusion: MSCT and MR perfusion are very helpful in the differentiation of benign soft tissue tumors from malignant ones. (author)