Various SPARCC cutoff values (based on the mean SPARCC score of the 2 readers) tested against the ASAS definition of a positive MRI, in reading campaign 1 and reading campaign 2.
| Positive MRI (ASAS) | Negative MRI (ASAS) | |
|---|---|---|
| Reading campaign 1, n = 294 | ||
| SPARCC ≥ 1 | 67 | 21 |
| SPARCC < 1 | 0 | 206 |
| κ: 0.82 | PA: 95.2% | NA: 86.5% |
| SPARCC ≥ 2 | 66 | 5 |
| SPARCC < 2 | 1 | 222 |
| κ: 0.94 | PA: 98.7% | NA: 95.7% |
| SPARCC ≥ 3 | 57 | 1 |
| SPARCC < 3 | 10 | 226 |
| κ: 0.89 | PA: 97.6% | NA: 91.2% |
| SPARCC ≥ 4 | 47 | 1 |
| SPARCC < 4 | 20 | 226 |
| κ: 0.77 | PA: 95.6% | NA: 81.7% |
| Reading campaign 2, n = 249 | ||
| SPARCC ≥ 1 | 31 | 5 |
| SPARCC < 1 | 0 | 213 |
| κ: 0.91 | PA: 98.8% | NA: 92.5% |
| SPARCC ≥ 2 | 31 | 1 |
| SPARCC < 2 | 0 | 217 |
| κ: 0.98 | PA: 99.8% | NA: 98.4% |
| SPARCC ≥ 3 | 25 | 0 |
| SPARCC < 3 | 6 | 218 |
| κ: 0.88 | PA: 98.6% | NA: 89.3% |
| SPARCC ≥ 4 | 21 | 0 |
| SPARCC < 4 | 10 | 218 |
| κ: 0.79 | PA: 97.8% | NA: 80.8% |
SPARCC cutoff values are based on the mean SPARCC scores of the 2 initial readers; in case there was a third reader involved, the mean of the SPARCC scores of the 2 readers in agreement of a “positive MRI” (ASAS definition) for that particular case were used. SPARCC: SpondyloArthritis Research Consortium of Canada; MRI: Magnetic resonance imaging; ASAS: Assessment of Spondyloarthritis International Society; PA: positive agreement; NA: negative agreement.