Background Inflammatory lesions (IL) on MRI of the sacroiliac joints show volatility over a short period of 3 months in patients (pts) with recent onset axial spondyloarthritis (axSpA)1.
Objectives To investigate whether the site and/or type of lesions in the spine change over a 3-month period in pts with recent onset axSpA/possible axSpA.
Methods 158 pts with back pain (≥3 months, ≤2 years, onset <45 years) included in the SPondyloArthritis Caught Early (SPACE)-cohort from the 5 participating centers underwent MRI of the spine (MRI-spine) at baseline and after 3 months. MRIs-spine were scored by 2 readers independently, blinded for the time sequence. Presence of corner inflammatory lesions (CIL; type A and B) and fatty lesions (FL) were scored2.3. Scores of both time points were compared on the vertebral unit level (VU; 23 per pt) for IL and on the quadrant level (Q; 4 per VU) for all lesions. Qs were summed (14536 in total) to study (changes in) the number, site and type of lesions. All possible changes were studied for each reader separately.
Results On the VU level, reader 1 scored no CIL at both time points in 98/158 pts (62.0%). In 16.5% of the pts the number of inflamed VUs increased over 3 months (mean 1.7 SD 1.3; range 1-4); in 21.5% the number decreased (mean -2.1 SD 1.6; range -7 to -1). The upper 9 VUs were almost never affected. On the Q level, no CIL and FL were scored at both time points in 68/158 (43.7%) pts. In 18 pts, lesions (in 9 pts CIL; in 6 pts FL; in 3 pts both CIL and FL) did not change over time (mean 1.9 SD 1.7; range 1-8). In 72/158 pts (45.6%) site and type of lesions changed over time; in 18/72 purely occurrence of lesions (any type) was seen (mean 1.7 SD 0.8; range 1-3) and in 19/72 purely resolving of lesions (any type) was seen (mean -2.2 SD 1.8; range -8 to -1). Within the remaining 35/72 pts, various types of changes were seen (e.g. occurrence of CIL in a Q and disappearance of FL in another Q etc; mean number of changed Qs 6.7 SD 5.1; range 1-22) as well as lesions that remained stable. Remarkably, more FL occurred in Qs without previous CIL (46 FL; in 23 pts) than in Qs with previous CIL (14 FL; in 7 pts), and 118 FL (whether or not surrounded by CIL) resolved over time (in 48 pts) (table). The results of reader 2 are very similar to reader 1 (table).
Conclusions Almost half of the pts (45.6%) showed changes in site and/or type of lesions in the spine over a 3-month period only. Noteworthy, FL occurred more frequently de novo than in Qs with previous CIL. Furthermore, FL can resolve over time. The value of FLs in the spine need to be re-evaluated.
de Hooge ARD 2012;71(Suppl3):301
Lambert J Rheumatol 2009;36 Suppl 84:3-17
Østergaard J Rheumatol 2009;36 Suppl 84:18-34
Disclosure of Interest None Declared