CT in necrotizing soft tissue infection: diagnostic criteria and comparison with LRINEC score

Objective To investigate which computed tomography (CT) criteria are most useful in diagnosing necrotizing soft tissue infection (NSTI) and how CT performs with respect to the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score. Methods Patients who underwent CT for suspected NSTI were eligible for inclusion. LRINEC score was assessed. CT scans were evaluated for subcutaneous edema, fluid along superficial fascia, fluid along deep fascia, blurring of intermuscular fat planes, fluid collection, and air in the soft tissues. Surgical findings or clinical follow-up served as reference standard. Results Fourteen patients with NSTI and 34 patients with non-NSTI were included. LRINEC score was significantly higher in patients with NSTI (median of 7.5 vs. 6, p = 0.039). Fluid along the deep fascia was significantly more frequently present in patients with NSTI (46.2% vs. 5.9%, p = 0.001). In multiple logistic regression analysis, presence of fluid along the deep fascia was significantly associated with NSTI (odds ratio [OR] = 10.28, 95% CI: 1.57 to 67.18, p = 0.015), whereas the LRINEC score was not significantly associated with NSTI (OR = 1.27, 95% CI: 0.92 to 1.74, p = 0.146). Using presence of fluid along the deep fascia as diagnostic criterion for NSTI, sensitivity was 46.2% (95% CI, 23.2 to 70.9%) and specificity was 94.1% (95% CI, 80.9 to 98.4%). Conclusion Fluid along the deep fascia was the only CT criterion which was significantly associated with NSTI and appeared more useful than the LRINEC score. In the right clinical setting, presence of this CT finding is highly suggestive for NSTI. Its absence, however, does not rule out NSTI.

Automated summary

The study found that fluid along the deep fascia was the only CT criterion significantly associated with NSTI and appeared to be more useful than the LRINEC score in diagnosing the condition.