Objective: The aim of the study was to describe the signal intensity (SI) behavior of soft tissue tumors (STT) on spin echo (SE) T1 weighted images (WI) with fat suppression (FS) and to assess its additional value in tissue characterization.
Methods: MRI signal characteristics of 53 histological proven STT were discussed. Signal intensity behavior of STT could be classified in 4 types, representing specific tissues or tissue components. Type 1 was defined as low SI on both SE T1-WI and SE T1-WI with FS. Type 2 was defined as high SI on both sequences. Type 3 consisted of high SI on T1-WI and low SI on T1-WI with FS. Type 4 was defined as SI comparable with SI of normal muscle on T1-WI and SI higher than normal muscle on T1-WI with FS. The additional information concerning contrast enhancement is described.
Results: Type 1 SI behavior was noted in fibrous lesions, in hemosiderotic components, cysts, and myxoma. Type 2 was noted in lesions containing methemoglobin or melanin. Type 3 was specific for fatty tissue. Type 4 was noted in highly cellular parts and in lesions of vascular origin. The use of SE T1-WI with FS improved lesion conspicuity on T1-WI.
Conclusions: E T1-WI with FS has additional value in the characterization of fibrous and hemosiderotic parts from cellular parts of lesions. It gives more confidence in characterization of neurogenic tumors and hemangioma's. Presence of methemoglobin and melanin are clearly discriminated from fatty tissue. Tumor conspicuity and inhomogeneity evaluation is improved. The use of SE T1-WI FS not only improves tumor conspicuity, but as tumor homogeneity and SI are important parameters in staging and characterization of STT, the use of SE T1-WI with FS will certainly be helpful. This may obviate the need for gadolinium administration.