Diffusion-Weighted Imaging Distinguishes Between Osteomyelitis, Bone Marrow Edema, and Healthy Bone on Forefoot Magnetic Resonance Imaging

Konrad A Kruk; Tobias J Dietrich; Simon Wildermuth; Sebastian Leschka; Andreas Toepfer; Stephan Waelti; Chan-Hi Olaf Kim; Sabine Güsewell; Tim Fischer

doi:10.1002/jmri.28091

Diffusion-Weighted Imaging Distinguishes Between Osteomyelitis, Bone Marrow Edema, and Healthy Bone on Forefoot Magnetic Resonance Imaging

J Magn Reson Imaging. 2022 Nov;56(5):1571-1579. doi: 10.1002/jmri.28091. Epub 2022 Feb 1.

Authors

Konrad A Kruk^{1

2}, Tobias J Dietrich^{1

2}, Simon Wildermuth^{1

2}, Sebastian Leschka^{1

2}, Andreas Toepfer³, Stephan Waelti^{1

2}, Chan-Hi Olaf Kim¹, Sabine Güsewell⁴, Tim Fischer^{1

2}

Affiliations

¹ Division of Radiology and Nuclear Medicine, Kantonsspital St. Gallen, St. Gallen, CH-9007, Switzerland.
² Faculty of Medicine, University of Zurich, Zurich, CH-8091, Switzerland.
³ Department of Orthopaedics and Traumatology, Kantonsspital St. Gallen, St. Gallen, Switzerland.
⁴ Clinical Trials Unit, Kantonsspital St. Gallen, St. Gallen, Switzerland.

PMID: 35106870
DOI: 10.1002/jmri.28091

Abstract

Background: Diagnosis of osteomyelitis by imaging can be challenging. The feasibility of diffusion-weighted imaging (DWI) as ancillary sequence was evaluated in this study.

Purpose: To evaluate DWI for differentiation between osteomyelitis, bone marrow edema, and healthy bone on forefoot magnetic resonance imaging (MRI).

Study type: Prospective.

Subjects: A total of 60 consecutive patients undergoing forefoot MRI divided into three study groups (20 subjects each): osteomyelitis, bone marrow edema, and healthy bone.

Field strength/sequence: A 1.5T and 3T MRI scanners; readout-segmented multishot echo planar DWI.

Assessment: Two independent radiologists measured apparent diffusion coefficient (ADC) values within abnormal or healthy bone.

Statistical tests: ADC values were compared between groups (pairwise t-test with Bonferroni-Holm correction for multiple testing). Intraclass correlation coefficient (ICC) was calculated to assess inter-reader agreement. Threshold ADC values were determined as the cutoffs that maximized the sum of sensitivity and specificity. Receiver operating characteristic (ROC) analysis was performed with statistical threshold of P < 0.05.

Results: Inter-reader agreement was 0.92 in the healthy bone group and 0.78 in both the edema and osteomyelitis groups. Average ADC values were significantly different between groups: 1432 ± 222 × 10^-6 mm² /sec (osteomyelitis), 1071 ± 196 × 10^-6 mm² /sec (bone marrow edema), and 277 ± 89 × 10^-6 mm² /sec (healthy bone). A threshold ADC value of 534 × 10^-6 mm² /sec distinguishes between healthy and abnormal bone with specificity and sensitivity of 100% each. For distinction between osteomyelitis and bone marrow edema, two cutoff values were determined: a 95%-specificity cutoff indicating osteomyelitis (>1320 × 10^-6 mm² /sec) and a 95%-sensitivity cutoff indicating bone marrow edema (<1155 × 10^-6 mm² /sec). Diagnostic accuracy of 95% was achieved for 73% (29/40) of the subjects.

Data conclusion: DWI with ADC maps distinguishes between healthy and abnormal bone on forefoot MRI. Calculated cutoff values allow confirmation or exclusion of osteomyelitis in a high proportion of subjects.

Evidence level: 2 TECHNICAL EFFICACY: Stage 2.

Keywords: bone marrow diseases; diffusion magnetic resonance imaging; magnetic resonance imaging; osteomyelitis.

MeSH terms

Bone Marrow / diagnostic imaging
Bone Marrow / pathology
Bone Marrow Diseases* / diagnostic imaging
Diffusion Magnetic Resonance Imaging / methods
Edema / diagnostic imaging
Humans
Magnetic Resonance Imaging
Osteomyelitis* / diagnostic imaging
Prospective Studies
Sensitivity and Specificity