Marrow edema

Bone marrow edema is the term given to abnormal fluid signal seen within the bone marrow on MRI. It is a non-specific, yet important finding usually indicating the presence of underlying pathology.

Pathology

Etiology

There is a long (long) list of possible causes of this finding:

Radiographic features

CT

Dual-energy CT may demonstrate bone marrow edema using fluid-sensitive "edema maps", however its sensitivity and specificity is poorer than that of MRI .

MRI

Bone marrow edema is generally primarily identified on MRI and is best investigated using fat-suppressed T2W sequences.

There will be intermediate T1 signal, with high T2 signal in the fat of the bone marrow (usually fat-suppressed sequences required to see the increased T2 signal).

However other imaging modalities may then have a role in investigating the underlying cause.