An introduction to identifying STIR images.
by Rossi Bad
Original Date: 2016-04
MRI image appearance
The best way to identify STIR images is to look for areas that should be filled with either fat or fluid. For example bone marrow should be filled with fat, and joint spaces should be filled with fluid. Next, you want to see that the fat is very dark, while the fluid is lighting up, and bright. Remember that STIR is a “fat suppression” technique that allows for detection of water and fluid content.
Therefore, muscle will appear darker than fat. Bone marrow, blood, fat (eg. subcutaneous), air will also appear dark. Fluids will appear very bright. Since pathological processes usually involve edema, which is an increase in the water content, this type of MRI is great for for pathological processes.
With regards to the podiatry, a minimal amount of fluid is found within tendon sheaths. This is usually clinically insignificant. However, fluid within the flexor hallucis longus tendon is a common finding, and should not be treated as pathological. This is due to the communication between the sheath of the FHL and ankle joint.
Therefore STIR is great for joint pathology, and tendon pathology.
The following website is a great resource for identifying and learning about imaging techinques!
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