Flash information
- T1 sequence
- Fat and volume
- STIR/fat-suppressed T2
- Water-sensitive signal
- Distribution
- Muscles and symmetry
- Specificity
- Non-specific oedema
Definition
Muscle MRI describes oedema, volume and fatty replacement; these dimensions are not interchangeable.
Examination or reading method
Compare T1 and water-sensitive sequences, right and left sides and different muscle groups.
Morphological description
STIR hyperintensity suggests increased water; fatty T1 signal and volume loss suggest structural damage.
Causes and diagnostic direction
Inflammatory myopathy, denervation, exercise, trauma and infection can alter muscle signal.
Differential diagnoses
Oedema does not diagnose myositis; distribution, clinical findings and laboratory testing distinguish causes.
Associated findings
Strength, muscle enzymes and evolution complement MRI; it may help select a biopsy site.
Red flags
Functional impact and extra-muscular involvement should be assessed independently of signal intensity.
Pitfalls and limitations
A single image does not represent all muscles; signal abnormalities and enzymes may be discordant.
Take-home message
Separate potential activity, damage and diagnosis; correlate MRI with clinical and, when indicated, pathological data.
Sources
- MRI and muscle imaging for idiopathic inflammatory myopathies - PMC ↗
- Update on muscle imaging in myositis - PMC ↗
Documentary review: 2026-10-12
Media source & rights
- Author
- Machado, Pedro*; Brady, Stefen*; Hanna, Michael G.
- Original source
- Machado, Pedro*; Brady, Stefen*; Hanna, Michael G., Inclusion_body_myositis_MRI.jpg, CC BY 3.0, Wikimedia Commons; conversion WebP et réduction proportionnelle.
- Licence
- CC BY 3.0
- Changes
- Conversion WebP, redimensionnement proportionnel sans recadrage ni annotations ajoutées; EXIF retiré. Dérivé écran proportionnel ≤1280 px, WebP qualité76 ; vignette ≤320 px qualité72. Source acquise et dérivé initial conservés sans modification ; aucune retouche médicale, aucun recadrage.
- Dimensions
- 960 × 934 px
- Check
- 2026-10-11T20:53:02.631419+00:00