What is reactive marrow edema on shoulder Mri?

Reactive marrow edema (RME) on shoulder MRI refers to a temporary condition where there is increased fluid and inflammation within the bone marrow of the shoulder joint. It's a common finding in various shoulder injuries, such as rotator cuff tears, labral tears, and impingement syndrome.

RME is the body's natural response to injury or stress. When the shoulder joint is subjected to trauma or overuse, the bone marrow responds by producing inflammatory mediators and increasing blood flow to the area. This leads to fluid accumulation and swelling within the bone marrow, resulting in reactive marrow edema.

On MRI, RME appears as a localized area of increased signal intensity (brightness) within the bone marrow. It can be seen on different MRI sequences, including T1-weighted, T2-weighted, and fluid-sensitive sequences like STIR (short tau inversion recovery) or PD (proton density). The extent and location of RME can help in identifying the underlying shoulder injury or pathology.

RME is typically a transient finding, and it usually resolves over time as the underlying injury heals. However, in some cases, persistent RME may indicate a more chronic or complex shoulder condition that requires further evaluation and management.

Overall, reactive marrow edema on shoulder MRI is a useful indicator of bone marrow changes associated with shoulder injuries and can assist in the diagnosis and monitoring of these conditions.