[Bone marrow edema: definition, diagnostic value and prognostic value]

Area of Science:

• Radiology
• Histopathology
• Medical Imaging

Context:

• Bone marrow edema (BME) is a common MRI finding, characterized by T1W hypointensity and T2W hyperintensity.
• The term 'edema' is histologically inaccurate, as findings often include fibrosis or inflammatory infiltrates, varying with etiology.
• In France, 'osteitis' is preferred for marrow signal changes in rheumatic diseases.

Purpose:

• To review the imaging features of bone marrow edema.
• To discuss the underlying etiologies of bone marrow signal changes.
• To evaluate the diagnostic and prognostic value of detecting bone marrow edema.

Summary:

• MRI findings of T1W hypointense and T2W hyperintense bone marrow are often mislabeled as 'edema'.
• Histological examination reveals diverse abnormalities, frequently involving fibrosis or inflammation, rather than true edema.
• Despite the misnomer, detecting these marrow signal changes is vital for diagnosis, prognosis, and management, particularly in rheumatic conditions.

Impact:

• Highlights the discrepancy between MRI terminology and histological findings for bone marrow abnormalities.
• Emphasizes the clinical significance of recognizing these changes for patient management and disease assessment.
• Suggests diffusion-weighted MRI may offer enhanced sensitivity for detecting bone marrow inflammation.