AOSSM/AANA Specialty Day 2020-MRI (Mis) Interpretation When to Worry, When to Chill

MRI (Mis) Interpretation When to Worry, When to Chill_

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This presentation by Dr. Hollis G. Potter at AAOS 2019 focuses on the interpretation challenges of bone marrow edema (BME) patterns on MRI, emphasizing when findings warrant concern versus benign interpretations. Bone marrow edema, best visualized on fat-suppressed sequences like STIR, reflects increased water mobility in the bone matrix and is sensitive but not specific—akin to a positive bone scan. Key considerations in interpretation include edema location (subchondral, central, or both compartments), presence of tidemark depression, adjacent lesions, surrounding soft tissue edema, and patient history including surgery or trauma.<br /><br />Clinical examples demonstrate various pathologies associated with BME patterns, such as subchondral fractures and infarctions, osteomyelitis, complex regional pain syndrome (CRPS), and tumors like chondroblastoma. MRI aids diagnosis by highlighting marrow and trabecular changes and the involvement of cortical bone. <br /><br />Additionally, Dr. Potter reviews MRI findings in osteochondral allografts (OCA), noting that most allografts remain intact without displacement, although poor incorporation occurs in about 22%, evidenced by subchondral marrow fibrosis and correlated subchondral bone collapse. MRI findings can also correlate with immune responses like anti-HLA antibody screening.<br /><br />The lecture included case studies illustrating longitudinal imaging post-OCA, trauma-related marrow changes, and unusual diagnoses such as osteoid osteoma causing posterior medial impingement. The integration of clinical history, careful evaluation of MRI marrow patterns, and recognition of the diverse causes of BME are critical for appropriate clinical decision-making.<br /><br />The presentation acknowledged the contributions of the HSS MRI Lab team and emphasized a multidisciplinary approach in interpreting complex bone marrow MRI findings to guide treatment and avoid unnecessary interventions.

Keywords

Bone Marrow Edema

MRI Interpretation

STIR Sequence

Subchondral Fractures

Osteomyelitis

Complex Regional Pain Syndrome

Osteochondral Allografts

Subchondral Marrow Fibrosis

Anti-HLA Antibody Screening

Osteoid Osteoma