Earliest investigation for diagnosis of Ankylosing spondylitis -

Dynamic MRI with fat saturation, either short tau inversion recovery (STIR) sequence or T1-weighted images with contrast enhancement, is highly sensitive and specific for identifying early intraarticular inflammation, cartilage changes, and underlying bone marrow edema in sacroiliitis. Magnetic resonance imaging allows for visualization of acute sacroiliitis, spondylitis, and can also detect acute inflammation of the entheses, bone, and synovium. The ability to detect early inflammation and accurately visualize cartilaginous and enthesal lesions makes magnetic resonance imaging a useful assessment tool in the spondyloarthropathies.