Dannish MRI study of 204 people (including 41 #AxSpA) shows that sacroiliac bone marrow edema is nonspecific, seen in 3-39% of non-SpA. Only SI erosions erosions, backfill & ankylosis were specific for axSpA. Few women w/ postpartum pain had SI erosion https://t.co/7iMaKGEafJ