Purpose: We retrospectively reviewed the diagnostic imaging findings (radiography, CT and US) of our cases of necrotizing fascitis of soft tissues looking for signs that could be useful for early and accurate diagnosis.
Material and methods: May 1991 to February 1998 we examined 130 patients with progressive necrotizing soft tissue infections; in 32 of them (22-84 years old) the retrospective pathologic diagnosis was necrotizing fascitis. Involved sites were the limbs (26/32), the cervical region (5/32) and the perineal region (1/32). Nineteen patients were submitted to conventional radiography, also for soft tissue studies. US was performed in an emergency setting in all the 32 cases, by a selected group of US operators particularly skilled in this kind of soft tissue condition. Contrast enhanced CT was performed in 9 cases.
Results: B-mode and Doppler US yielded useful and reliable information for prompt and correct diagnosis. Particularly these techniques showed changes in subcutaneous adipose tissue (28/32), fascia (18/32) and muscle (15/32). We found a good correlation between tissue changes as shown at US and histologic findings, but US missed changes in subcutaneous soft tissue and muscle in 11 cases (3/32 and 8/32, respectively) with subsequent histologic confirmation. Contrast enhanced CT better defined the extent of disease and possible complications, especially in sites that are difficult to study with US.
Discussion and conclusions: Early diagnosis and proper treatment are the key issues affecting the chances of recovery for patients with necrotizing fascitis. The clinical suspicion of this condition calls for prompt intervention with effective diagnostic protocols. B-mode, and sometimes color Doppler, US and contrast enhanced CT, together with appropriate laboratory tests, can provide useful information for precise diagnosis and proper treatment.