Background/Purpose: The existence of a gut-joint axis is widely described in spondyloarthritis, linking intestinal dysbiosis, subclinical gut inflammation, and arthritis. The fat halo sign is believed to arise from chronic inflammation, leading to transmural edema and infiltration of the bowel wall by inflammatory cells and fat. This radiologic finding has a high prevalence in patients with inflammatory bowel disease(IBD). This study aims to define the prevalence of the fat halo sign in a well-defined cohort of patients with psoriatic arthritis (PsA) and assess its potential clinical significance.

Methods: This is a cross-sectional study involving PsA patients followed prospectively from a collaborative site of an international cohort. All patients fulfilled the CASPAR criteria. Patients who have undergone routine abdominal CT scan for various clinical indications constituted the study population. Two radiologists have independently recorded the presence of the fat halo sign in the stomach, terminal ileum, and the ascending/transverse/descending colon and rectum. Demographics and disease characteristics of patients with positive fat halo were compared to patients without fat halo using descriptive statistics as appropriate.

Results: Of the 328 patients followed, 101 completed an abdominal CT scan. The mean age was 63.7±15 of whom 49 (48.5%) were males with a disease duration of 8.4±8.7 years, 19% on non-steroidal anti-inflammatory drugs, 55% were on disease-modifying anti-rheumatic drugs and 57% were on biologics. 3.9% had a history of IBD, and 4.2% had a history of uveitis. 38/101 (37.6%) patients had a positive halo sign in at least one section (as illustrated in Figures 1 and 2). The presence of halo sign was more common in males (65.8 vs. 31.8%, p=0.007) and more likely in patients with nail lesions (31.6 vs 15.9%, p=0.06). Other patient’s demographic and disease characteristics, disease activity parameters and treatment regimen were not statistically different.

Conclusion: Fat halo is common in patients with psoriatic arthritis and was observed in 38% of patients, of whom only a minority had IBD. It was more frequent in males, however, not associated with any of other patient’s demographics, disease characteristics, disease activity parameters or treatment regimen.

Contrast-enhanced coronal CT image shows fatty infiltration within the bowel wall of the descending colon at the level of the left colic flexure.

Non-contrast axial CT image shows fatty infiltration within the bowel wall of the ascending colon at the level of the right colic flexure

« Back to ACR Convergence 2025

ACR Meeting Abstracts - https://acrabstracts.org/abstract/prevalence-and-clinical-significance-of-the-gastrointestinal-fat-halo-sign-in-patients-with-psoriatic-arthritis-a-cross-sectional-study/