Learning objectives
The purpose of this educational poster is to provide a practical pattern approach of the muscle edema findings at MRI.
After reading this poster,
the reader will be able to:
Mention the possible causes of abnormal signal intensity in skeletal muscle.
Recognize clinical findings and different patterns of muscle edema at MRI imaging that help to narrow the differential diagnosis.
Background
The diagnostic images and particularly magnetic resonance imaging (MRI) have an important role in the detection and characterization of the different pathologies of the skeletal muscle.
The normal skeletal muscle has an intermediate signal intensity,
wich is slightly higher than water and much lower than fat on T1-weighted images,
and much lower tan both fat and water on T2-weighted images.
Muscle edema is characterized by T2 prolongation due to increased intracellular or extracellular free water,
which can be detected in liquid sensitive sequences such as...
Findings and procedure details
Muscle edema can occur from a variety of causes,
such as trauma,
subacute denervation,
during and after muscle exercise,
early myositis ossificans,
infectious myositis with abscess formation and autoimmune conditions.
Muscle contusions are caused by trauma.
The direct blow causes interstitial hemorrhage and edema,
which is evident in the MR images at the site of the injury and compromise the overlying subcutaneous tissues.
More severe cases may have hematomas and thus appears as a masslike lesion in addition to edema.
Muscle denervation in the subacute...
Conclusion
There are many potential causes of muscular edema and MRI is the imaging method of choice for its visualization.
Knowledge of these conditions,
combined with recognition of the pattern of abnormal signal intensity,
clinical information and findings from other imaging studies,
frequently helps to narrow the differential diagnosis.
References
May DA,
Disler DG,
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Abnormal Signal Intensity in Skeletal Muscle at MR Imaging: Patterns,
Pearls,
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Morrison y Timothy G.
Sanders.
Solución de problemas en imagen musculoesquelética.
ELSEVIER 2008.
Schulze M,
Kötter I,
Ernemann U,
et al.
MRI findings in inflammatory muscle diseases and their noninflammatory mimics.
AJR 2009.
Colm J.
McMahon,
Jim S,
Wu
Ronald L.
Eisenberg.
Muscle Edema.
AJR 2010.
Soler R,
Rodriguez E,
Aguilera C,
Fernandez R.
Magnetic resonance imaging of...