Necrotizing fasciitis versus pyomyositis: discrimination with using MR imaging.

Area of Science:

• Radiology
• Medical Imaging
• Infectious Diseases

Background:

• Necrotizing fasciitis (NF) and pyomyositis (PM) are distinct soft tissue infections.
• Accurate differentiation is crucial for appropriate treatment and patient outcomes.

Purpose of the Study:

• To evaluate magnetic resonance (MR) imaging findings for differentiating between NF and PM.
• To identify specific MR criteria that distinguish these two conditions.

Main Methods:

• Retrospective review of MR images from 19 patients with surgically or pathologically confirmed NF (n=11) or PM (n=8).
• Analysis focused on the presence or absence of specific MR findings on T2-weighted and contrast-enhanced T1-weighted fat-suppressed sequences.

Main Results:

• Peripheral band-like hyperintense signal, peripheral band-like muscle enhancement, and thin smooth deep fascia enhancement were more prevalent in NF (p < 0.05).
• Diffuse muscle hyperintensity, diffuse muscle enhancement, thick irregular deep fascia enhancement, and intramuscular abscesses were more common in PM (p < 0.05).
• Superficial fascia and muscle hyperintensity on T2 and enhancement on T1 were seen in all patients.

Conclusions:

• MR imaging findings are valuable in differentiating between necrotizing fasciitis and pyomyositis.
• Specific patterns of muscle and fascial enhancement on MR imaging can reliably distinguish NF from PM.