Qualitative and quantitative assessment of sacroiliitis in axial spondyloarthropathy: can a single T2-weighted dixon sequence replace the standard protocol?

Abstract

To compare the accuracy and repeatability for the assessment of axial spondyloarthritis (axSpA) between single T2-weighted (W) Dixon and the standard protocol (T1W and fat-suppressed T2W sequence). One hundred and seven patients were diagnosed based on the Assessment in SpondyloArthritis International Society (ASAS) criteria by rheumatologists. Two radiologists reviewed two protocols separately. Positive MRI, active sacroiliitis, chronic sacroiliitis, Spondyloarthritis Research Consortium of Canada (SPARCC) scores, and Sacroiliac Joint (SIJ) Structural Score (SSS) scores were recorded. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of bone marrow oedema (BME) and fat deposition were measured. No significant difference in diagnostic performance was observed between T2W Dixon sequence and the standard protocol (all p>0.05). Diagnostic performance of positive MRI was not significant difference between the T2W Dixon sequence and the standard protocol (area under the curve [AUC], 0.73-0.75 versus 0.74-0.76). Cohen's kappa coefficients and intraclass correlation coefficients (ICCs) showed similar intra-observer and interobserver agreements. Of note, interobserver agreements of BME and fat metaplasia on the T2W Dixon sequence were slightly higher than the standard protocol. SNRs and CNRs were significantly higher on the T2W Dixon than the standard protocol (all p≤0.05). The single T2W Dixon sequence may replace the standard protocol in patients with suspected axSpA and shorten the acquisition time.