Single-Centre Analysis of Magnetic Resonance Imaging of Sacroiliac Joints in a Paediatric Population

<b>Background:</b> Sacroiliitis in children is usually connected with one of the subtypes of juvenile idiopathic arthritis (JIA), such as enthesitis-related arthritis, psoriatic arthritis, or undifferentiated arthritis. The main diagnostic method is magnetic resonance imaging (MRI) of the sacroiliac joints, which can reveal bone marrow edema (BME) as a sign of an active inflammation process. This research aimed to retrospectively investigate the associations between the clinical presentation, laboratory test results, and MRI results of the sacroiliac joints of children. <b>Methods:</b> A total of 152 paediatric patients who underwent MRI of the sacroiliac joints were included in this single-centre study. The mean age of patients was 13.91 ± 2.97, while the female-to-male ratio was 1.36:1. JIA diagnosis was confirmed in 91 (59.87%) patients. <b>Results:</b> The main symptom reported by 128 (83.21%) patients was chronic pain, while in another 40 (31.25%) patients, it was chronic back pain. Patients with arthritis and BME in the sacroiliac joints were more likely to report chronic back pain, while patients with JIA but without BME in the sacroiliac joints were often positive for anti-nuclear antibodies (ANA). The widening of any joint contour was observed in 43 (28.29%) patients, and reduced joint mobility was observed in 61 (40.13%). Elevation of inflammatory blood parameters occurred in 31 (20.39%) patients, but this was not statistically related to BME presence in the sacroiliac joints. Radiological findings included BME (n = 36; 23.68% of examinations), joint space narrowing (n = 10; 27.78% of examinations), erosions (n = 7; 19.44% of examinations), and joint fluid (n = 7; 19.44% of examinations). There was a statistically significant relationship between the presence of BME in the sacroiliac joints and all of the above radiological findings. <b>Conclusions:</b> The radiological findings of MRI of the sacroiliac joints are significantly statistically related to chronic back pain in patients, while there is no relationship between any inflammatory blood parameter and the presence of BME.