MRI and Clinical Risk Indicators for Osteomyelitis

Area of Science:

• Radiology
• Orthopedics
• Infectious Diseases

Background:

• Osteomyelitis diagnosis relies on imaging, with MRI showing 90% sensitivity and 80% specificity.
• Key MRI findings include bone marrow edema, hyperintensity on T2-weighted images (HI-T2WI), confluent signal on T1-weighted images (CS-T1WI), and cortical erosion (CE).

Purpose of the Study:

• To identify risk factors and MRI findings most predictive of osteomyelitis in foot and ankle biopsies.
• To evaluate the association between patient characteristics, MRI indicators, and histological diagnosis of osteomyelitis.

Main Methods:

• Retrospective review of 59 patients undergoing foot/ankle bone biopsy (2015-2017).
• Histological confirmation of osteomyelitis diagnosis.
• Blinded MRI review for indicators: HI-T2WI, CS-T1WI, ulcer depth, and CE.
• Bivariate and multivariate regression analysis to determine risk factors.

Main Results:

• Diabetes (RR=2.9), CS-T1WI (RR=1.6), and CE (RR=1.8) were significant risk factors on bivariate analysis.
• Diabetes (RR=2.4) and CE (RR=1.7) were independent risk factors on multivariate analysis.
• Radiologist diagnosis sensitivity was 51.4%, specificity 91.7%.

Conclusions:

• Diabetes and CS-T1WI are independent risk factors for pedal osteomyelitis.
• Patients with diabetes, CS-T1WI, and CE require careful evaluation for osteomyelitis.
• Bone biopsy is recommended for definitive diagnosis in appropriate clinical settings.