Can Bone Erosion in Axial Spondyloarthropathy be Detected by Ultrashort Echo Time Imaging? A Comparison With Computed Tomography in the Sacroiliac Joint

Abstract

Background Structural lesion evaluation in axial spondyloarthropathy (SpA) can improve accuracy of diagnosis. However, structural lesions (bone erosions) are difficult to be assessed using conventional MRI compared to computed tomography (CT). Purpose To evaluate the diagnostic performance of ultrashort echo time (UTE) for detecting bone erosion in axial SpA compared to T1WI and three‐dimensional double‐echo steady‐state (3D DESS) imaging using CT as the reference standard. Study Type Retrospective. Population Fourteen patients (eight females, 57.1%) and 14 healthy controls (seven females, 50.0%) who underwent sacroiliac (SI) joint MRI and CT. Field Strength/Sequence 3 T; TSE T1WI, 3D DESS, 2D UTE. Assessment The bilateral SI joints were assessed for bone erosion. Three observers scored bone erosion for all three sequences of MRI. CT was used as the gold standard. Diagnostic confidence in axial SpA was measured based on a four‐point confidence score. Statistical Tests Correlation of erosion scores between CT and MRI were evaluated using Spearman's correlation test. Sensitivity, specificity, and positive–negative predictive values were calculated. Confidence scores were compared using the Wilcoxon sum rank test. Statistical significance was set at P < 0.05. Results Compared with erosion scores of CT, the correlation coefficients for each MRI sequence showed significant low‐to‐high positive correlations (0.39–0.72). UTE imaging showed the highest correlation coefficients for all observers (0.70, 0.72, and 0.67, respectively). The specificity of UTE imaging was equal or higher than those of T1WI and 3D DESS for all observers (0.86 vs. 0.71 vs. 0.57; 0.93 vs. 0.71 vs. 0.57; 0.79 vs. 0.79 vs. 0.43). All observers had the highest confidence in interpreting UTE imaging for detecting bone erosion among the three sequences (3.5, 3.4, and 3.3 for UTE; 3.1, 3.0, and 2.6 for T1WI; and 3.2, 2.7, and 2.4 for DESS). Data Conclusion UTE imaging can detect bone erosions in patients with axial SpA and show higher specificity than conventional T1WI and 3D DESS. Evidence Level 4 Technical Efficacy Stage 2

Assessment of the sacroiliac joint in patients with axial spondyloarthritis via three-dimensional ultrashort echo time magnetic resonance imaging

“…This provides outstanding contrast between the articular cartilage and the bone cortex interface. Hahn et al found that 2D-UTE imaging provided better diagnostic performance for identifying SIJ bone erosion than did T1-weighted imaging and 3D DESS sequences ( 19 ). In our study, fewer erosions were detected with the 3D-UTE sequence than with CT.…”

Is it time to move on from pelvic radiography as the first-line imaging modality for suspected sacroiliitis?

“…In addition, several MRI sequences sensitive to cortical structures that may allow accurate cortical and trabecular bone assessment have been recently reported [52 ▪▪ ,53,54–56]. These pulse sequences, including 3D MRI such as zero echo time (ZTE) and ultrashort echo time (USTE) as well as black bone (BB) sequences, add an average of 4–5 min to the total MRI examination time and were shown to be more accurate as well as more specific and sensitive than T1-w sequences for the detection of erosions, sclerosis, and joint space changes [52 ▪▪ ,57 ▪▪ ] while at the same time performing similar to CT in the assessment of bony structures of the SIJs (Fig. 4) [58 ▪ ].…”