Assessment of active spinal inflammatory changes in patients with axial spondyloarthritis: Validation of whole body MRI against conventional MRI
- Christian W A Pfirrmann (christian.pfirrmann{at}balgrist.ch)
- Kaspar Rufibach (kaspar.rufibach{at}ifspm.uzh.ch)
- Muhammad A Khan (mkhan{at}metrohealth.org)
Abstract
Objective: To evaluate the performance of whole body (WB) MRI versus conventional (CON) MRI in assessing active inflammatory lesions of the entire spine in patients with established and clinically active axial spondyloarthritis (SpA) using the Spondyloarthritis Research Con-sortium of Canada (SPARCC) MRI index.
Methods: 32 consecutive SpA patients fulfilling the modified New York criteria and with clinically active disease (BASDAI score ≥ 4) were scanned by sagittal WB and CON MRI of the spine. The MR images were scored independently in random order by 3 readers blinded to patient identifiers. Active inflammatory lesions of the spine were recorded on a web-based scoring form. Pearson correlation coefficient served to compare scores for WB and CON MRI for each rater whilst intra-class correlation coefficient (ICC) was used to assess inter-observer reliability.
Results: The median percentage of inflammatory lesions recorded concordantly for both WB and CON MRI ranged from 83% to 91% for the 3 readers; 4% to 9% were only recorded by WB MRI, and 4% to 9% were recorded by CON MRI only. The Pearson correlation coeffi-cient between WB and CON MRI per rater was 0.79, 0.89 and 0.81, respectively. The ICC(2, 1) for CON MRI was 0.75, 0.80 and 0.68 and for WB MRI 0.82, 0.83 and 0.93, respectively, for the 3 possible reader pairs.
Conclusion: WB and CON MRI scores showed a high correlation and comparable high reli-ability for the detection of active inflammatory lesions in the spine of patients with clinically active SpA.
