Dense bone around the sacroiliac joint: a radiological review of the differential diagnosis

Prevalence of CT features of axial spondyloarthritis in patients with Crohn's disease

Background The sacroiliac joint and spine are seen on abdominal computed tomography (CT) and may show structural lesions as part of spondyloarthritis. Purpose To determine the prevalence of CT features of spondyloarthritis in patients with Crohn's disease (CD). Material and Methods A retrospective study of structural lesions of spondyloarthritis on abdominal CT was performed. The sacroiliac joints and spine of 120 patients were studied: study group I consisted of 40 patients with known CD and inflammatory back pain, group II involved 40 patients with CD without inflammatory back pain, and group III consisted of 40 patients without known joint or inflammatory bowel disease. Recorded CT features included sclerosis, erosions or ankylosis of the sacroiliac joint, enthesopathy, spinal syndesmophytes, and costovertebral joint lesions. Results CT showed structural lesions of the sacroiliac joints in 19/40 (48%) patients with CD and inflammatory back pain (sclerosis [n = 14; 35%], erosions [n = 14; 35%], ankylosis [n = 3; 8%]), in 8/40 (8%) patients with CD without inflammatory back pain (sclerosis [n = 3; 8%], erosions [n = 4; 10%], ankylosis [n = 3; 8%]), and in 3/40 (8%) patients without known joint or bowel disease (sclerosis [n = 2; 5%], ankylosis [n = 1; 3%]). Syndesmophytes were exclusively seen in group I (n = 6; 15%). Conclusion CT of the abdomen in patients with CD and inflammatory back pain shows structural lesions of the sacroiliac joint, entheses, or spine in almost half of the patients. Awareness and knowledge of these findings may guide the referring clinician to further clinical evaluation, imaging, and biomarker evaluation of the disease.

Enteropathic arthritis in the sacroiliac joint. Imaging and differential diagnosis

OBJECTIVES

A new high resolution computed tomography (HRCT) scoring system of sacroiliac joint (SIJ) involvement in enteropathic arthritis is introduced.

PATIENTS AND METHODS

SIJ's of 100 patients were studied. A total of 25 patients presented with pain syndrome, 25 with suspicious seronegative spondylarthritis, 25 with inflammatory bowel diseases and 25 without joint or bowel diseases, as a control group. HRCT was carried out in all 100 patients. For comparison, a plain film radiography (PFR), conventional CT (slices of 10 mm) and bone scan were used.

RESULTS

Quantitative differences: In the pain syndrome group, there were no erosions identified neither intraarticular calcifications. Disc degeneration was seen in 12/25 cases. In 4/25 patients, vacuum phenomena appeared in the SIJ. In 3/25 patients, ventral capsular calcification occurred in the ventral sacroiliac ligament (anterior capsule complex). In the seronegative spondylarthritis group, 16/25 patients had positive findings, while PFR documented erosions only in 3/25 cases. In the bowel diseases group, erosions were detected in 17/25 cases with HRCT, while the plain film was positive only in three cases and in seven cases the findings were questionable. Intraarticular calcification with erosion was documented in three cases and in seven cases without erosion. The bone scan was positive in 7/25 of this cases, but in 5/7 there was mismatching with HRCT. Important new finding was the HRCT detected erosion which was not detected on BS but was obvious on Anti-Granulocyte-Antibody scintigraphy. In the control group, only degenerative changes were seen in 4/25 cases and no erosions.

CONCLUSION

HRCT is: (1) the reliable imaging of definitive (often 'cold stage') sacroileitis; (2) gives optimal detection of erosion; and (3) appears to be the only method in the documentation of calcifications in the posterior ligamental portion of the SIJ.