Sacroiliac Joint MRI May Aid Diagnosis of AxSpA in Non-Rheumatology Settings

July 30, 2025

Sacroiliac Joint MRI May Aid Diagnosis of AxSpA in Non-Rheumatology Settings

A study published recently in Seminars in Arthritis and Rheumatism examined the early detection of axial spondyloarthritis (axSpA) in young adults with chronic back pain who were referred to non-rheumatology specialists. The study, called SHERPAS (short for Strategy for a Hospital Early Referral in Patients with Axial Spondyloarthritis) was designed to assess how often axSpA is present in this patient population and to evaluate the use of MRI of the sacroiliac joints (SI joints) as a diagnostic tool.

Researchers conducted SHERPAS from July 2021 to October 2023. The observational study enrolled adults ages 18 to 40 who had chronic back pain and were referred for spinal MRI by specialists other than rheumatologists. As part of the study, participants completed questionnaires about their back pain characteristics and features associated with spondyloarthritis. In addition to the scheduled spinal MRI, each patient underwent MRI of the SI joint. Subsequently, all participants were evaluated by a rheumatologist, who determined whether axSpA was present based on clinical and imaging data.

Of the 268 participants, 8 individuals (3.0%) were diagnosed with definite axSpA, and 14 more (5.2%) were identified as suspected cases. This resulted in a combined prevalence of 8.2% for definite or suspected axSpA. Certain clinical features were found to be more common among patients diagnosed with axSpA: buttock pain, symptom improvement with NSAIDs, shorter duration of symptoms, HLA-B27 positivity, and elevated C-reactive protein (CRP) levels.

MRI findings showed that while degenerative spinal lesions were common across the cohort, abnormalities in the SI joint (which often indicates the presence of inflammatory disease) were observed in nearly one-third of participants and were more frequent among those with axSpA.

The researchers note that this study highlights the importance of improving early identification of axSpA in patients who may not initially present to rheumatology. Since these individuals often seek care from other specialists, key signs of axSpA may be overlooked, contributing to diagnostic delays. The SHERPAS study highlights that combining clinical features with SI joint MRI in non-rheumatology settings may aid in earlier detection and referral, which is critical for timely management and better long-term outcomes.

Resources:

1. Science Direct – Can we identify axial spondyloarthritis among young adults referred to non-rheumatology specialists? Results from the SHERPAS study
2. Spondylitis Association of America – MRI Diagnosis for Persistent Back Pain
3. Spondylitis Association of America – Could Your Chronic Back Pain Be Caused by Spondyloarthritis?