MAGNETIC-RESONANCE-IMAGING DIFFERENTIATES BETWEEN NECROTIZING AND NONNECROTIZING FASCIITIS OF THE LOWER-EXTREMITY

Background: Distinction between uncomplicated infective fasciitis and early necrotizing fasciitis can be extremely difficult without operati on, yet the management and prognosis of both conditions depend greatly on early recognition and assessment of the extent of involvement. Stu dy Design: This was a prospective review of the utility of magnetic re sonance imaging (MRI) in nine patients with suspected infective or nec rotizing fasciitis treated at an academic medical center or a Veterans Administration hospital. Results: Magnetic resonance imaging document ed fascial inflammation, characterized by low intensity on T-1-weighte d images and high intensity on T-2-weighted images, in all nine patien ts. Absence of gadolinium contrast enhancement on T-1-weighted images reliably detected fascial necrosis in all six patients who required op erative debridement. Magnetic resonance imaging was extremely useful i n defining the extent of fasciitis and was more accurate in predicting necrosis or pyomyositis than was myoglobinuria or elevation of serum creatine kinase or lactate dehydrogenase. Operation was avoided in two patients without evidence of necrosis on MRI. One patient without evi dence of necrosis, explored because of contradictory clinical findings , was confirmed at operation to have cellulitis without necrosis. Conc lusions: Magnetic resonance imaging with gadolinium contrast accuratel y determines the presence of necrosis and the need for operation in pa tients with fasciitis of the lower extremity. Preoperative determinati on of the extent of involvement facilitates operative planning. (J Am Cell Surg 1998;187:416-421. (C) 1998 by the American College of Surgeo ns).