Backfill, follow-up MRI after five years (T1SE sequence). Five years later, the same patient as in Figure 3 shows marked progression of structural lesions in both SIJ with ankylosis in previous areas of backfill (arrows). MRI, magnetic resonance imaging; SIJ, sacroiliac joint; T1SE, T1-weighted spin echo sequence.
Weber et al. Arthritis Research & Therapy 2012 14:R124 doi:10.1186/ar3854