The prevalence of sacroiliitis on abdominal MRI examinations of patients with Takayasu arteritis

Background Takayasu arteritis (TA), a systemic large-vessel vasculitis, was reported to have high incidence of spondyloarthropathy. Purpose To evaluate the prevalence of inflammatory sacroiliitis in patients with TA that underwent abdominal/pelvic magnetic resonance imaging (MRI) examinations as part of their vasculitis work-up. Material and Methods Consecutive abdominal/pelvic MRI examinations of 34 patients with TA fulfilling the 1990 ACR criteria and 34 age- and gender-matched controls performed between 2008 and 2020 were retrospectively reviewed for the presence sacroiliitis. The presence of active and structural lesions was scored twice (with a one-month interval between reads) by one reader. Structural lesions were also evaluated on computed tomography, when available, and correlated to MRI findings. Clinical data were extracted from the patients' clinical files. MRI scores were compared between the study and control groups and correlated with the clinical data. Results Sacroiliitis was evident in 11.7% of the TA group examinations compared to 0.3% in the control group (P = 0.6). Participants with TA had significantly more erosions and fat deposition compared to the control group (Study: 0.01/0.03, Control: 0/0, P = 0.03/0.003, respectively). However, mean sacroiliitis score was not significantly different (Study: 1.06, Control: 0.78, P = 0.015). Of the four patients with TA and sacroiliitis, 3 (75%) had a diagnosis of inflammatory bowel disease (IBD). Conclusion Sacroiliitis was detected in 11.7% of abdominal MRI examinations of patients with TA, 75% of which had associated IBD, suggesting that both IBD and sacroiliitis should be routinely screened in the TA population as their presence may influence treatment decisions.