Necrotizing fasciitis: CT characteristics.

PURPOSE: To establish computed tomographic (CT) criteria for the diagnosis of necrotizing fasciitis.

MATERIALS AND METHODS: Twenty CT scans in 20 patients with pathologically proved necrotizing fasciitis were reviewed retrospectively for fascial thickening, fat infiltration, focal fluid collection, soft-tissue gas, muscle involvement, and intra-abdominal extension; the findings were correlated with clinical factors, including associated illnesses, disease site, treatment, and outcome.

RESULTS: Average patient age was 57.8 years; there were 13 men and seven women. Four patients (20%) died. Asymmetric fascial thickening and fat stranding were seen in 16 patients (80%). Gas tracking along fascial planes was present in 11 patients (55%), and abscesses were found in seven patients (35%). Infection sites were scrotum (n = 6), a lower extremity (n = 4), perineum (n = 4), neck (n = 2), back (n = 2), arm (n = 1), and abdomen (n = 1). Underlying illness (n = 17) was diabetes in 10 patients (50%), alcoholism in three (15%), chronic renal failure in two (10%), and drug abuse in two (10%).

CONCLUSION: CT criteria of asymmetric fascial thickening and gas are valuable in assessing suspected necrotizing fasciitis. CT also can provide information on coexistent deep collections.