Multivariate analyses of MRI findings for predicting osteomyelitis of the foot in diabetic patients

Abstract

Background There have been no previous magnetic resonance imaging (MRI) studies using multivariable analysis to diagnose osteomyelitis in patients with diabetic foot. Purpose To retrospectively investigate the MRI findings of osteomyelitis in patients with diabetic foot using multivariate analyses. Material and Methods From November 2015 to March 2018, 118 patients who underwent MRI of the foot to evaluate suspected osteomyelitis were included in this study. The patients were categorized into the presence or absence of osteomyelitis. The primary and secondary MRI findings were retrospectively reviewed. To identify independent predictive MRI findings, multivariate analyses with binary logistic regression and receiver operating characteristic curve analyses were performed including all 118 patients and 93 patients presenting decreased T1 signal intensity, respectively. Results T1 signal intensity, T1 marrow pattern, T1 marrow distribution, T2 signal intensity, concordance of marrow signal intensity, cortical interruption, ulcer depth, abscess, and wet gangrene were significantly different between the two groups ( P < 0.05). Multivariate analyses indicated that fluid equivalent T2 signal intensity, deep ulcer, and confluent T1 marrow pattern were major factors associated with osteomyelitis. The area under the curve of predicted probabilities for the combination of these factors was 0.799 across all 118 patients and 0.761 across 93 patients with decreased T1 signal intensity. Conclusion Confluent T1 marrow pattern is a reliable finding to suggest osteomyelitis in patients with diabetic foot. In addition, fluid equivalent T2 signal intensity and deep ulcer are important findings that may suggest osteomyelitis, irrespective of T1 signal intensity change.

Foot Osteomyelitis Location and Rates of Primary or Secondary Major Amputations in Patients With Diabetes

“…If osteomyelitis was suspected because of a positive probe-to-bone test and/or the presence of clinical symptoms, conventional radiographs (cortical erosions or destruction without prior surgery or trauma) and magnetic resonance imaging (MRI; bone marrow suppression on T1-weighted images, bone marrow edema in a fluid-sensitive MR sequence) were performed. 24 , 25 , 29 In case of MRI contraindications, bone scintigraphy or 18F-fluorodeoxyglucose positron emission tomographic / computed tomographic scans were used instead. Intraoperative biopsy of the affected bone was further used to confirm the diagnosis and to acquire a microbiologic profile.…”

Classification Model for Diabetic Foot, Necrotizing Fasciitis, and Osteomyelitis

“…LR is a frequently used approach for predicting DFU infections [ 28 , 29 ]. Furthermore, efforts have been made to establish a prediction model for NF and OM using LR [ 30 , 31 ]. Likewise, we could establish the classification model for DFU infections using LR based on the ML technique.…”

Magnetic resonance imaging of musculoskeletal infections

“…Infected bone should have bone marrow oedema signal on fluid-sensitive images, and confluent low signal on T1W images ( Figures 18B - D ). Recent studies have shown that in patients with diabetic foot ulcers, bone marrow oedema with increased signal on fluid-sensitive sequences and preserved T1W signal frequently progresses to osteomyelitis, especially in ulcers larger than 3 cm that involve greater than 50% of subcutaneous fat or with a sinus tract extending to bone, and when the bone marrow fluid signal region of interest measurement to joint fluid region of interest measurement ratio is greater than 53% [ 52 , 101 - 104 ]. Occasionally, there may be non-visualization of the cortical margins of the infected bone on the T1W images (known as the “ghost sign”), with the cortical margins visualized on both the fluid-sensitive and contrast-enhanced images, which may be helpful in the diagnosis of superimposed infection in a neuropathic foot [ 14 , 31 , 33 , 41 , 52 , 100 ].…”