Table 1.
Imaging abnormalities ‘typical of axSpA’ observed in the axSpA and mechanical chronic back pain groups
| CBP n=98‡ | axSpA n=100 | p | |||||
| Xrays | Pelvic Xrays | Lesions | Erosion (y/n)* | 9/97(9.3%) | 35(35.0 %) | <0.001§ | |
| Sclerosis (y/n) | 21/97(21.6%) | 50(50.0%) | <0.001 | ||||
| Joint widening (y/n) | 13/97 (13.4%) | 25 (25.0%) | NS | ||||
| Joint narrowing (y/n) | 11/97 (11.3%) | 21 (21.0%) | NS | ||||
| Partial ankylosis (y/n) | 7/97 (7.2%) | 11 (11.0%) | NS | ||||
| Total ankylosis (y/n) | 0 | 3 (3.0%) | NS | ||||
| At least a grade two unilateral | 26/96(27.1%) | 54(54%) | <0.001 | ||||
| Modified NY criteria | 11/95(11.6%) | 35(35.0%) | <0.001 | ||||
| Spine Xrays | Lesions | Number of erosions | 0.4 (0.8) | 0.3 (0.5) | NS | ||
| Number of sclerosis lesions | 0.4 (1.6) | 0.5 (1.4) | NS | ||||
| Number of squaring lesions | 0.01(0.1) | 0.2(0.8) | 0.037 | ||||
| Number of patients with at least one full bone bridge | 2 (2.1%) | 5 (5.0%) | NS | ||||
| MRI | Inflammatory lesions | Sacroiliac joints | At least one inflammatory lesion | 24/95(25.3%) | 40(40.0%) | 0.028 | |
| ASAS definition of MRI sacroiliitis | 8/95(8.4%) | 35(35.0%) | <0.001 | ||||
| ASAS definition of MRI sacroiliitis AND deep lesion† | 1/95(1.1%) | 17(17%) | <0.001 | ||||
| ASAS definition of MRI sacroiliitis AND intense lesion† | 2/95(2.1%) | 20(20%) | <0.001 | ||||
| ASAS definition of MRI sacroiliitis AND (deep OR intense lesion)† | 3/95(3.2%) | 24(24%) | <0.001 | ||||
| ASAS definition of MRI sacroiliitis AND (deep AND intense lesion)† | 0 | 13(13%) | <0.001 | ||||
| Spine | At least one inflammatory lesion | 44 (44.9%) | 52/99 (52.5%) | NS | |||
| At least three inflammatory lesions (ASAS definition of positive spine MRI) | 33 (33.7%) | 44/99 (44.4%) | NS | ||||
| At least five inflammatory lesions | 25 (25.5%) | 30/99 (30.3%) | NS | ||||
| Structural lesions | Sacroiliac joints | At least one structural lesion | 16/95 (16.8%) | 24 (24%) | NS | ||
| At least three erosions | 10/95 (10.5%) | 32 (32%) | < 0.001 | ||||
| At least three fatty lesions | 11/95 (11.6%) | 29 (29%) | 0.004 | ||||
| At least five erosions or fatty lesions | 13/95 (13.7%) | 33 (33%) | 0.002 | ||||
| Spine | At least one structural lesion | 49 (50.0%) | 42/99 (42.4%) | NS | |||
| At least three erosions | 6 (6.1%) | 7/99 (7.1%) | NS | ||||
| At least three fatty lesions | 21 (21.4%) | 15/99 (15.2%) | NS | ||||
| At least five fatty lesions | 12 (12.2%) | 9/99 (9.1%) | NS | ||||
| At least five structural lesions (erosions OR fatty lesions) | 19 (19.4%) | 11/99 (11.1%) | NS |
*Results are presented as n(%) for dichotomous variables and as mean (SD) for continuous variables.
†According to the SPARCC scoring of the SIJ.
‡In case no denominator is indicated, the available images are n=98 for CBP and n=100 for axSpA.
§Significant results are highlighted in bold.
ASAS, Assessment of SpondyloArthritis international Society; CBP, chronic back pain; NY, New York; SPARCC, Spondyloarthritis Research Consortium of Canada index; axSpA, axial Spondyloarthritis.