Comparison of STIR and spin-echo MR imaging at 1.5 T in 45 suspected extremity tumors: lesion conspicuity and extent. Short inversion time inversion recovery (STIR) imaging and a double-echo spin-echo (SE) sequence at 1.5 T in 45 sequential patients with suspected extremity tumors were compared to assess the number of lesions detected, subjective conspicuity of lesions, approximate volume of abnormality detected in each lesion, and identification of peritumoral brightening in tissues adjacent to each lesion. STIR sequences enabled detection of all 45 lesions; 44 were detected with the SE sequence. Tumor appeared most conspicuous on STIR images in 35 patients (78%) and was most conspicuous on SE images in 10 patients (22%). Peritumoral brightening, which indicated either peritumoral edema or microscopic tumor infiltration, was detected in 20 patients but was detected only with STIR sequences in nine patients. It is concluded that, although STIR and SE sequences are comparable for lesion detection in the extremities, most lesions appear more conspicuous with STIR. STIR may enable detection of a greater volume of abnormality than SE sequences and may therefore have important implications for local staging and surgical and radiation therapy planning. 