Evaluation of Bone Cortex and Cartilage of Spondyloarthropathic Sacroiliac Joint: Efficiency of Different Fat-Saturated MRI Sequences (T1-Weighted, 3D-FLASH, and 3D-DESS)

Rationale and Objectives: Accurate assessment of the morphology of sacroiliac joint (SIJ) bone cortex and cartilage bears importance in terms of detecting sacroiliitis in its earliest period. The aim of this study was to evaluate the efficacies of fat-saturated T1-weighted (T1WFS) spin-echo, three-dimensional (3D)-fast low angle shot (3D-FLASH), and 3D-double excitation in the steady-state (3D-DESS) sequences for the detection of SIJ cartilage and bone cortex abnormalities in patients with clinically suspected active sacroiliitis. Materials and Methods: Magnetic resonance imaging (MRI) was performed in 9 controls and 30 patients with suspected active sacroilitis. T1WFS, short tau inversion recovery, 3D-DESS with FS, 3D-FLASH with FS, postcontrast (the same precontrast T1WFS sequence) T1WFS, and subtracted images were obtained in all the cases. The bone cortex and cartilaginous morphology were visually scored on the T1WFS, 3D-DESS, and 3D-FLASH images. MRI findings were statistically evaluated. Results: Active sacroiliitis was observed in 28 patients (49 SIJs) that were examined by postcontrast and subtracted images. T1WFS, 3D-DESS, and 3D-FLASH images revealed cartilage erosions in 26 (47 SIJs), 28 (55 SIJs), and 28 (55 SIJs) patients, respectively. Cartilage and bone cortex erosion scores in SIJs were significantly higher in 3D-DESS and 3D-FLASH images than in T1WFS images (P<.05). Bone erosion scores assessed on T1WFS and 3D-FLASH images of active sacroiliitis patients, were found to be significantly different (P<.05). A similar relationship was not determined between 3D-DESS and T1WFS sequences (P>.05). Conclusion: