MRI Scan SI Joint Test is done in order to detect sacroiliac joint dysfunction. This test is instructed by a doctor only if the physical test does not determine the exact cause of the pain. If the patient is suffering from severe low back pain, then only this test is recommended after performing physical tests. Some of the indications of sacroiliac joints are a neoplasm of joints, infections in bones or joints, degenerative arthritis, sacroiliitis, ankylosing spondylitis, psoriasis, osteoarthritis, and gout. Sacroiliac joints pain is hard to find because sacroiliac is present deep inside the pelvis. Hence many tests are performed to detect the dysfunction of the sacroiliac joint.