Spondyloarthritis endgame: MRI versus BoneMRI in sacroiliitis

The Assessment in SpondyloArthritis International Society (ASAS) classification criteria characterize sacroiliitis by active inflammation and structural lesions. Detection of lesions such as bone marrow edema, joint surface erosions and ankylosis is important, because progressing treatment options benefit from early diagnosis and detailed treatment response monitoring. Recent technological advancements have made various imaging modalities available to assess these findings, i.e., various sorts of CT (low dose, dual energy, etc.), MRI and BoneMRI. BoneMRI is an advanced technique where CT-like images are reconstructed from a dedicated MRI sequence, opening opportunities to better characterize structural lesions than on a classic MRI study. The scope of this review is to provide an overview of the pros and cons of MRI and BoneMRI in sacroiliitis and demonstrate the inherent added value of BoneMRI towards state-of-the-art routine MRI sequences.