Volume 27, Issue 7 e15246
ORIGINAL ARTICLE

MRI predictors of infectious etiology in patients with unilateral sacroiliitis

Madhavi Kandagaddala

Madhavi Kandagaddala

Department of Radiology, Christian Medical College, Vellore, Tamil Nadu, India

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Kirthi Sathyakumar

Corresponding Author

Kirthi Sathyakumar

Department of Radiology, Christian Medical College, Vellore, Tamil Nadu, India

Correspondence

Kirthi Sathyakumar, Department of Radiology, Christian Medical College, Vellore, Tamil Nadu, India.

Email: [email protected]

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Ashish Jacob Mathew

Ashish Jacob Mathew

Department of Clinical Immunology and Rheumatology, Christian Medical College, Vellore, Tamil Nadu, India

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Soumya Susan Regi

Soumya Susan Regi

Department of Radiology, Christian Medical College, Vellore, Tamil Nadu, India

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Bijesh Yadav

Bijesh Yadav

Department of Biostatistics, Christian Medical College, Vellore, Tamil Nadu, India

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Kenny David

Kenny David

Department of Spine Surgery, Christian Medical College, Vellore, Tamil Nadu, India

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Debashish Danda

Debashish Danda

Department of Clinical Immunology and Rheumatology, Christian Medical College, Vellore, Tamil Nadu, India

Deceased.

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First published: 28 June 2024
Citations: 3

Abstract

Background

Unilateral presentation of sacroiliitis is a diagnostic dilemma, especially between infection and inflammatory sacroiliitis associated with spondyloarthritis, requiring an early and accurate diagnosis.

Objective

To assess the utility of magnetic resonance imaging (MRI) in differentiating infective versus inflammatory etiology in unilateral sacroiliitis.

Materials and Methods

Retrospective review of the MRI of 90 patients with unilateral sacroiliitis, having an established final diagnosis. MR images were evaluated for various bone and soft tissue changes using predefined criteria and analyzed using univariate and multivariate regression analysis.

Results

Among the 90 patients, infective etiology was diagnosed in 66 (73.3%) and inflammatory etiology in 24 (26.7%). Large erosions, both iliac and sacral-sided edema, joint space involvement with effusion or synovitis, soft tissue edema, elevated ESR/CRP, and absence of capsulitis and enthesitis were associated with infection (p < .001). The independently differentiating variables favoring infection on multivariate analysis were—both iliac and sacral-sided edema (OR 4.79, 95% CI: 0.96–23.81, p = .05), large erosions (OR 17.96, 95% CI: 2.66–121.02, p = .003), and joint space involvement (OR 9.9, 95% CI: 1.36–72.06, p = .02). Exclusive features of infection were osteomyelitis, sequestra, abscesses, sinus tracts, large erosions, and multifocality. All infective cases had soft tissue edema, joint space involvement, elevated ESR, and no capsulitis.

Conclusion

MRI evaluation for the presence and pattern of bone and joint space involvement, soft tissue involvement, and careful attention to certain exclusive features will aid in differentiating infectious sacroiliitis from inflammatory sacroiliitis.

CONFLICT OF INTEREST STATEMENT

The authors declare that there is no conflict of interest.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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