Imaging of necrotizing fasciitis.

Necrotizing Fasciitis (NF) is a rare, but highly lethal, rapidly progressive necrotic infection of the soft-tissue fascia. More common in immunocompromised patients, NF typically affects the extremities, perineal area, genital area (Fournier gangrene), and less commonly the torso. Although classically a clinical diagnosis, imaging is a powerful adjunct to facilitate early diagnosis in equivocal cases. The key features of NF of radiography, ultrasound, CT, and MRI are reviewed, as are the inherent limitations of NF diagnosis for each modality. With a high level of sensitivity, specificity, and soft tissue contrast, MRI remains the gold standard imaging method for evaluation of NF.