Sacroiliitis

(Upper panel) Coronal T1-weighted MRI of the sacroiliac joints reveals decreased signal in the sacrum and the iliac in the region of the inferior left sacroiliac joint (arrows). (Middle panel) Coronal T2- weighted MRI reveals corresponding hyperintense signal in the inferior left sacroiliac joint (arrows). (Bottom panel) Axial T1- weighted MRI with fat saturation following intravenous gadolinium injection demonstrates intense enhancement of the left sacroiliac joint. These findings are most compatible with sacroiliitis in a patient with inflammatory bowel disease.