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Updated: Jun 25, 2026
Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease
Published on: December 18, 2016
Necrotizing fasciitis versus pyomyositis: discrimination with using MR imaging
Jee Hyun Seok1, Won-Hee Jee, Kyung-Ah Chun
1Department of Radiology, The Catholic University of Korea, Seoul, Korea.
Objective:
We wanted to evaluate the MR findings for differentiating between necrotizing fasciitis (NF) and pyomyositis (PM).
Materials And Methods:
The MR images of 19 patients with surgically confirmed NF (n = 11) and pathologically confirmed PM (n = 8) were retrospectively reviewed with regard to the presence or absence of any MRI finding criteria that could differentiate between them.
Results:
The patients with NF had a significantly greater prevalence of the following MR findings (p < 0.05): a peripheral band-like hyperintense signal in muscles on fat-suppressed T2-weighted images (73% of the patients with NF vs. 0% of the patients with PM), peripheral band-like contrast enhancement (CE) of muscles (82% vs. 0%, respectively) and thin smooth enhancement of the deep fascia (82% vs. 13%, respectively). The patients with PM had a significantly greater prevalence of the following MRI findings (p < 0.05): a diffuse hyperintense signal in muscles on fat-suppressed T2-weighted images (27% of the patients with NF vs. 100% in the patients with PM), diffuse CE of muscles (18% vs. 100%, respectively), thick irregular enhancement of the deep fascia (0% vs. 75%, respectively) and intramuscular abscess (0% vs. 88%, respectively). For all patients with NF and PM, the superficial fascia and muscle showed hyperintense signals on T2-weighted images and CE was seen on fat-suppressed CE T1-weighted images. The subcutaneous tissue and deep fascia showed hyperintense signals on T2-weighted images and CE was seen in all the patients with NF and in seven (88%) of the eight patients with PM, respectively.
Conclusion:
MR imaging is helpful for differentiating between NF and PM.
Insights
Magnetic resonance (MR) imaging can differentiate between necrotizing fasciitis (NF) and pyomyositis (PM). Key MR findings like peripheral band-like signals and enhancement in muscles help distinguish NF from PM.
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.
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