Diagnostic performance of MRI and CT in diagnosing necrotizing soft tissue infection: a systematic review

Abstract

Objective To systematically review the accuracy of MRI and CT in diagnosing necrotizing soft tissue infection (NSTI). Methods MEDLINE and Embase were searched for original studies which reported the diagnostic performance of MRI or CT in detecting NSTI. Individual study quality was assessed using the QUADAS-2 tool. Sensitivity and specificity of MRI and CT were calculated and, if supported by data from at least two studies, pooled using a bivariate random-effects model. Results Six MRI studies and 7 CT studies were included. There were no major concerns with regard to study quality and applicability. The included studies used multiple diagnostic criteria, with sensitivities and specificities of both MRI and CT ranging between 0 and 100%. T2 hyperintensity of deep fascia was the most commonly used diagnostic MRI criterion (5 studies), yielding a pooled sensitivity of 86.4% (95% confidence interval [CI] 76.1-92.7%) and a pooled specificity of 65.2% (95% CI 35.4-86.6%). Presence of gas was the most commonly used diagnostic CT criterion (3 studies), yielding a pooled sensitivity of 48.6% (95% CI 37.1-60.2%) and a pooled specificity of 93.2% (95% CI 73.3-98.5%). Conclusion T2 hyperintensity of deep fascia at MRI has high sensitivity and moderate specificity in diagnosing NSTI. Presence of gas at CT has low sensitivity but high specificity. A combination of diagnostic criteria may improve diagnostic performance, but this needs further investigation.

Contemporary strategies for diagnosis and management of necrotizing soft tissue infections: Α review

“…The diagnosis of NSTI/NF relies on clinical findings and can further be supplemented and supported by several diagnostic adjuncts, including common laboratory tests, plain x-rays (to detect air in soft tissues), the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) scoring system (proposed score >6 for NF), the Fournier's Gangrene Severity Index, ultrasonography (US),enhanced computed tomography (CT) and magnetic resonance imaging (MRI) at the site of infection, and fascia biopsy [4][5][6]14,[18][19][20][26][27][28]. Special imaging is important in diagnosis in equivocal cases as well as for the assessment of the infectious extent and severity [1,4,14,27].…”

Imaging of Musculoskeletal Soft-Tissue Infections in Clinical Practice: A Comprehensive Updated Review

“…When present, gas is more easily demonstrated than plain radiographs. In a recent review, the presence of gas in CT had a pooled sensitivity and specificity of 48.6% and 93.2%, respectively [32]. In addition to gas along the fascia, other common CT findings include increased density and stranding (edema) in the subcutaneous fat, edema and thickening of the superficial and deep fascia, blurring of the intermuscular fascial planes, nonenhancement of the fascia, and fluid collection [13,33].…”

“…Gas can be identified as signal void on all pulse sequences and shows blooming on gradient recalled-echo sequence. The other key finding in NF is a high fluid-sensitive signal along the deep peripheral fascia, which has pooled sensitivity and specificity of 86.4% and 65.2% [32]. The absence of a high fluid-sensitive signal along the deep fascia essentially excludes NF.…”

Schwerpunkt Ophthalmopathologie Orbitainfektion: vom Hordeolum bis zur nekrotisierenden Fasziitis

“…For necrotizing fasciitis in other body regions, MRI examination has high sensitivity but lower specificity. Computed tomography can detect gas formation in tissue with high specificity [26].…”

“…Für die nekrotisierende Fasziitis in anderen Körperregionen gilt, dass die MRT-Untersuchung eine hohe Sensitivität, jedoch geringere Spezifität hat. Die CT kann Gasbildung im Gewebe mit hoher Spezifität erkennen [26].…”