Dynamic contrast enhanced MRI in the differential diagnosis of soft tissue tumors.

PURPOSE: The value of the dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) in differentiating benign and malignant soft tissue tumors was investigated.
MATERIALS AND METHODS: Turbo FLASH DCE-MRI was performed on 22 subjects (2-74 years) with soft tissue tumors. Enhancement in the first min (E(max/1)), second min (E(max/2)) and maximum peak enhancement (E(max)), and steepest slope were calculated. Discriminant analyses were performed to reveal parametric differences of benign and malignant lesions.
RESULTS: Diagnosis of benign (N = 10) tumors were hemangioma (n = 3), neurogenic tumor (n = 3) lipoma (n = 2), giant cell tumor (n = 1) and desmoid (n = 1), whereas malignant lesions (N = 12) were classified as liposarcoma (n = 5), malignant fibrous histiocytoma (n = 5) and synovial sarcoma (n = 2). For malignant lesions E(max/1) was 65-198%, E(max/2) was 65-145%, E(max) was 78-198%, and steepest slope was 1.45-4.06. For benign lesions these values were 4-98%, 5-105%, 7-125% and 0.67-2.57, respectively. To determine the relation between the variables analysed, Pearson correlation coefficients were calculated. E(max) was found to be highly correlated with other variables (rxy > 0.86, P < 0.0001). Consequently, this variable was excluded from the discriminant analysis. In order to determine discrimination of malignant and benign tumors using E(max/1), E(max/2,) and steepest slope of the enhancement curve logistic regression was applied to the above mentioned data. When combined these parameters had a 95.5% of overall accuracy in classifying benign and malignant lesions (P = 0.004).
CONCLUSION: DCE-MRI parameters that thought to be the surrogate markers of tumoral microcirculation and tissue perfusion provides a specific preoperative diagnosis. Dynamic imaging parameters are therefore advocated for monitoring the effect of chemotherapy in soft tissue tumors.