The Role of Computed Tomography in the Diagnosis of Necrotizing Soft Tissue Infections.

BACKGROUND: The exact role of IV contrast-enhanced computed tomography (CT) in the diagnosis of necrotizing soft tissue infections (NSTIs) has not yet been established. We aimed to explore the role of CT in patients with clinical suspicion of NSTI and assess its sensitivity and specificity for NSTI.

METHODS: The medical records of patients admitted between 2009 and 2016, who received IV contrast-enhanced CT to rule out NSTI, were reviewed. CT was considered positive in case of: (a) gas in soft tissues, (b) multiple fluid collections, (c) absence or heterogeneity of tissue enhancement by the IV contrast, and (d) significant inflammatory changes under the fascia. NSTI was confirmed only by the presence of necrotic tissue during surgical exploration. NSTI was considered absent if surgical exploration failed to identify necrosis, or if the patient was successfully treated non-operatively.

RESULTS: Of the 184 patients, 17 had a positive CT and hence underwent surgical exploration with NSTI being confirmed in 13 of them (76%). Of the 167 patients that had a negative CT, 38 (23%) underwent surgical exploration due to the high clinical suspicion for NSTI and were all found to have non-necrotizing infections; the remaining 129 (77%) were managed non-operatively with successful resolution of symptoms. The sensitivity of CT in identifying NSTI was 100%, the specificity 98%, the positive predictive value 76%, and the negative predictive value 100%.

CONCLUSIONS: A negative IV contrast-enhanced CT scan can reliably rule out the need for surgical intervention in patients with initial suspicion of NSTI.