X-ray vs MRI: Selecting First-line Imaging for Patients With Axial Spondyloarthritis

Ideal patient age and symptom duration were identified to guide use of X-ray vs magnetic resonance imaging (MRI) in the diagnosis of axial spondyloarthritis. Researchers published their findings in Therapeutic Advances in Musculoskeletal Disease.

“Imaging is crucial for the diagnosis of [axial spondyloarthritis] as it is the only method that can objectively detect inflammatory changes in the axial skeleton,” authors wrote. “In some patients, sacroiliitis can be detected by X-ray as well as by MRI, whereas in other patients, sacroiliitis can be detected only by MRI.”

The retrospective cohort study involved 388 participants. Imaging modalities were used on sacroiliac joints to determine whether newly diagnosed patients had radiographic (raxSpA) or nonradiographic (nraxSpA) axial spondyloarthritis.

The cohort included 322 patients with raxSpA and 66 patients with nraxSpA. Patients with nraxSpA were younger at time of diagnosis compared to patients with raxSpA (35.7 ± 11.3 years vs 26.8 ± 7.8 years, P < .001). Additionally, symptom duration was shorter in the nraxSpA cohort [5.1 (2.1-12) years vs 1 (.5-3.2) years, P < .001].

Using receiver operating characteristic curve analysis, authors determined the use of X-ray was appropriate in patients over 33.5 years of age (AUC: .734) who had symptoms for over 4.1 years (AUC: .787), while MRI should be used for patients of younger ages with shorter symptom durations.

Authors concluded, “patients older than 33.5 years with a symptom duration longer than 4.1 years are highly likely to have radiographic axSpA rather than nonradiographic axSpA. Therefore, for these patients, using X-ray as a first-line imaging modality could be sufficient to make a diagnosis, saving time and expense of performing an MRI.”

Reference:
Kwon OC, Park MC. Selection of x-ray versus magnetic resonance imaging as a first-line imaging modality for diagnosing axial spondyloarthritis. Ther Adv Musculoskelet Dis. Published online February 14, 2022. doi:10.1177/1759720X211072994