Deep fascial hyperintensity in soft-tissue abnormalities as revealed by T2-weighted MR imaging

OBJECTIVE. The purpose of this study was to determine whether recently described criteria, including hyperintense T2-weighted signal or other abnormalities revealed by MR imaging within deep fascial planes, are specific for necrotizing soft-tissue infections. MATERIALS AND METHODS. We reviewed 22 MR imaging examinations that revealed abnormally high signal intensity within deep fascial planes on T2-weighted images. Twenty-one of the patients had clinical diagnoses other than necrotizing soft-tissue infection, including nonnecrotizing cellulitis (n = 4), abscess without evidence of necrotizing fasciitis (n = 5), and cellulitis with accompanying vascular thrombosis (n = 2). MR imaging was performed using T1-weighted spin-echo (range of TRs/range of TEs, 300-800/9-30) and fat-saturated T2-weighted fast spin-echo (3000- 5000/76-108) sequences. Gadolinium-enhanced T1-weighted spin-echo MR images with fat saturation were obtained for 14 patients. Two reviewers, unaware of clinical diagnoses, evaluated each study for abnormalities in superficial and deep soft tissues and submitted a consensus diagnosis. RESULTS. Using only the described MR imaging criteria, we interpreted all cases as necrotizing cellulitis, including the cases of 21 patients who had nonnecrotizing conditions. CONCLUSION. Hyperintense T2-weighted signal within deep fascial planes and muscle, with or without contrast enhancement, is not specific for necrotizing soft-tissue infection. A variety of conditions exhibited similar findings and were indistinguishable from necrotizing soft-tissue infection.