Magnetic Resonance Imaging of the Sacroiliac Joints in Patients with Suspected Spondyloarthritis – Comparison of Turbo Spin-Echo and Gradient-Echo Sequences for the Detection of Structural Alterations

Abstract

Purpose: Magnetic resonance imaging (MRI) is the method of choice for the evaluation of spondyloarthritis (SpA). According to the guidelines of the Assessment of Spondyloarthritis International Society (ASAS) and Outcome Measures in Rheumatology (OMERACT), MRI findings in SpA of the spine and the sacroiliac joints (SIJ) are classified as inflammatory and structural alterations. Modern gradient-echo sequences (GRE) are recommended for optimized detection of structural alterations of the SIJ. We assess the benefit of GRE in the detection of structural alterations of the SIJ in comparison to conventional turbo spin-echo sequences (TSE). Material and Methods: Retrospective study of 114 patients who received MRI of the SIJ for the evaluation of SpA. Structural alterations of the SIJ were assessed by two blinded readers separately for T1 TSE and T2* GRE. The findings were classified according to a previously published chronicity score separately for both sides and sequences. Interobserver reliability was calculated with Cohen?s Kappa, and the significance of findings was assessed with the Wilcoxon test. P-values <?0.05 were required for statistical significance. Results: 68 of 114 (60?%) patients showed SpA-typical findings of the SIJ. The average chronicity score for GRE (score 3.3) was significantly higher than for TSE (score 2.6), p?=?0.001. The Kappa-values for the interobserver reliability were 0.86???0.90 without any statistically significant differences between both sides and sequences. Conclusion: Both T1 TSE and T2* GRE showed a high interobserver reliability in the detection of structural alterations in patients with SpA. However, T2* GRE detected significantly more structural alterations than T1 TSE and should be an integral part of a modern MRI protocol for the diagnostic workup of patients with suspected SpA. Key points: ??T2* gradient-echo sequences are superior to T1 turbo spin-echo sequences in the detection of structural SI-joint alterations. Citation Format: ??Dornia C, Fleck M, Hartung W et?al. Magnetic Resonance Imaging of the Sacroiliac Joints in Patients with Suspected Spondyloarthritis ? Comparison of Turbo Spin-Echo and Gradient-Echo Sequences for the?Detection of Structural Alterations. Fortschr R?ntgenstr 2015; 187: 109???114

Magnetic Resonance Imaging of the Axial Skeleton in Patients With Spondyloarthritis: Distribution Pattern of Inflammatory and Structural Lesions

“…Through our use of gradient echo sequences with SIJ studies, however, the sensitivity of MRI could be increased. 15,23 Another limitation may lie in the fact that the patient population has a rather low systemic disease activity.…”

“…For the inflammatory lesions, the scoring system of the Spondyloarthritis Research Consortium of Canada (SPARCC) was applied. 12,13 The structural MRI findings of the SIJ were assessed using the chronicity score by Hermann et al 14,15 For the structural lesions of the spine, the Stoke Ankylosing Spondylitis Spine Score (SASSS) was used. 16 Hoffstetter et al…”

“…The score includes 4 degrees of severity regarding sclerosis, erosions, and ankylosis of the SIJ and assigns corresponding values of 0 to 4. 14,15 The right and left SIJs were rated separately from one another and then formed a total score with a maximum value of 8.…”