THE ROLE OF DIFFUSION-WEIGHTED MRI IN THE CHARACTERIZATION OF MUSCULOSKELETAL SOFT-TISSUE TUMORS

Abstract

This essay aimed at evaluation of the role of Diffusion-Weighted MRI in the detection and characterization of the musculoskeletal soft tissue tumors and determining whether benign or malignant. DWI is an unenhanced functional MRI technique that can be incorporated into routine MRI examinations with less than 5 minutes of additional acquisition time. With important warnings related to the presence of abscesses, hematomas, and lipid, lower ADC values reflect increased tumor cellularity, and ADC maps can be useful in the initial characterization of both bone and soft-tissue tumors and in post treatment evaluation. The Apparent Diffusion Coefficient (ADC) generated by measuring identical images at different b-values and represented as ADC map from which ADC value calculated. The diagnosis is confirmed after the MRI examination by histologic biopsy according to standard histopathological procedures in most of the cases. There is a significant difference in the mean ADC value between benign and malignant soft tissue tumors (P < 0.01). The mean ADC value of benign is significantly higher than that of malignant soft tissue tumors. The ADC value might be useful for diagnosing the malignancy of nonmyxoid soft tissue tumors that, if the ADC value exceeds 1.3 x 10-3 mm2/s in nonmyxoid tumors, the possibility of malignancy is low. Therefore, to conclude, MRI is the method of choice in detection and characterization of musculoskeletal soft tissue masses, however the development of new MRI techniques, DWI with ADC mapping has proved to be a valuable non-invasive tool in differentiating benign and malignant soft tissue tumors with highly significant difference between ADC value of benign and malignant tumors especially the non-myxoid ones.