MRI of soft-tissue lesions: opposed-phase T2*-weighted gradient-echo images

We evaluated the ability of opposed-phase T2*-weighted gradient-echo (T2*GE) MRI to demarcate soft tissue lesions. The series contained 37 cases, including 18 benign tumors, 8 malignant tumors, and 11 miscellaneous nonneoplastic soft-tissue lesions. Images were obtained on a 0.5 T magnet with T2*GE imaging (TR/TE 300/22 ms, 20 degrees). Results were compared with those of T1-weighted SE images (500/20-40) and T2-weighted SE (T2SE) images (2,000/80). The T2*GE images were similar to T2SE images with respect to the signal behavior and internal architecture of the masses in many cases. In some instances, they were better than T2SE images in delineating the lesions and adjacent fat tissue, in delineating the lesions and adjacent small vessels, and in depicting special features such as hemosiderin deposits. They were inferior to T2SE images in delineating the lesions and adjacent muscles. Because of reduced lesion-muscle delineation, T2*GE images can not be substituted for T2SE images in the evaluation of soft-tissue lesions, but are useful as an adjunct in some cases.