CT manifestations of ankylosing spondylitis

Ankylosing spondylitis is a very common disease, and there are many causes of ankylosing spondylitis. In fact, if you want to treat ankylosing spondylitis, you need to go to the hospital for various examinations and cooperate with the doctor to actively receive treatment. This can effectively control the disease in time and then treat it symptomatically. Generally speaking, if you suffer from ankylosing spondylitis, you need to rest well while actively receiving treatment.

What are the CT manifestations of ankylosing spondylitis?

Typical CT findings of sacroiliitis include subchondral bone sclerosis at the sacral end, unilateral or bilateral joint space <2mm, subchondral bone erosion, and partial or complete ankylosis of the joint. The main manifestations of CT are abnormal width of the sacroiliac joint space, uneven thickness of the iliac cortical bone, blurred articular surface, focal or diffuse decalcification, varying degrees of plaque-like and diffuse bone hyperplasia and sclerosis beside the joint at the anterior edge of the joint, brush-like or serrated erosion of the bone edge, worm-like changes, subchondral cystic changes, and cortical bone interruption. In the late stage, the sacroiliac joints become ankylosed, the bones are mostly decalcified and sparse, and ligament erosion and cystic changes are common.

MRI findings

Inflammation of the synovium and surrounding ligaments of the apophysis joints. The acute phase of ankylosing spondylitis involves the synovium of the joint cavity, joint capsule, ligaments, and tendons, causing edema of the affected tissues and surrounding bone marrow, blurring of the affected joint space, and changes in the upper and lower articular process bone marrow, pedicle bone marrow, soft tissue around the joints, spinous process bone marrow, and interspinous ligaments. Almost all patients have varying numbers of facet joint blurring and stenosis, some of which are bilaterally symmetrical; some are asymmetrical and have worm-like changes in the facet joint cartilage and hyperplasia. The sacroiliac joint cartilage is destroyed, abnormal signals are visible in the joint, and subchondral bone is eroded. Bone erosion and ankylosis of the vertebral body, intervertebral disc junction and facet joints. The intervertebral disc signal can vary in many ways, which is related to the degree of fibrosis. Hip effusion is an early manifestation of hip joint involvement, and hyperplastic inflammatory synovial tissue may be seen in the advanced stage.

The X-ray manifestations of early sacroiliac arthritis are sometimes difficult to determine. The main reason is that the sacroiliac joint has a complex anatomical structure, its morphology varies from person to person, and it is easily interfered by the pelvic structure, which is not conducive to the early diagnosis of the disease. CT has high resolution and no interference between layers, which is helpful for detecting slight changes in the sacroiliac joint. CT can more clearly show the anatomical location and distribution range of the sacroiliac joint, the integrity of the bone cortex, and the invasion of adjacent tissues, and can provide a basis for early clinical diagnosis, staging, and treatment plans. Magnetic resonance imaging of the sacroiliac joints shows adjacent bone marrow edema, and MRI can be used as evidence of the active stage of ankylosing spondylitis by showing joint edema.