MRI abnormalities of sacroiliac joints in early spondylarthropathy: a 1-year follow-up study

OBJECTIVE

To describe changes in chronic and acute magnetic resonance imaging (MRI) abnormalities of the sacroiliac joints (SIJs) in early spondylarthropathy (SpA), and to associate these findings with computed tomography (CT), X-ray, and clinical findings during a 1-year follow-up.

METHODS

Thirty-four patients, 20 males and 14 females, median age 27 years, with inflammatory low back pain (median 23 months) were included. MRI, CT, and X-ray, as well as clinical and laboratory tests were performed. After a follow-up period of 1 year (median 377 days) the examinations were repeated, and the findings were correlated.

RESULTS

MRI and CT changes resulting from SIJ destruction increased significantly during follow-up, and the two modalities were significantly correlated. For the MRI findings of inflammatory activity, only bone marrow oedema decreased significantly. An increase in the Schober test was the only clinical examination that changed significantly.

CONCLUSION

In early SpA, MRI can detect significant inflammatory and destructive changes of the SIJs over a 1-year follow-up period, in spite of minimal changes in the clinical parameters. The MRI changes in inflammatory activity are not detectable by CT and X-ray examinations. Thus, MRI may be a sensitive method, without known risks, for early diagnosis and for following disease progression in SpA.

Magnetic resonance imaging of sacroiliitis in early seronegative spondylarthropathy. Abnormalities correlated to clinical and laboratory findings

OBJECTIVE

To compare a new MRI scoring system of the sacroiliac joints (SIJs) in early spondylarthropathy (SpA) with clinical and laboratory parameters.

METHODS

Forty-one patients (24 males, 17 females) with a median age of 26 yr and a median duration of inflammatory low back pain of 19 months were included. They all fulfilled the ESSG-criteria for SpA. The patients were examined by MRI of the SIJs using a new scoring system. Clinical examinations, biochemical tests, functional score (BASFI), and pain score (BASDAI) were also performed.

RESULTS

95% of the patients had inflammation and/or destructive bone changes of the SIJs at MRI. No correlation was found between MRI pathology and clinical findings. MRI demonstrated significantly greater severity of both inflammation and destruction of the SIJs in HLA B27 positive patients than in the HLA B27 negative patients.

CONCLUSIONS

In patients with early SpA, MRI was able to detect inflammatory and destructive changes of the SIJs, but the changes were not associated to clinical findings. Our results suggest a role of MRI in the detection of early-stage sacroiliitis.

MR imaging of the normal sacroiliac joint with correlation to histology

OBJECTIVE

The microscopic study of the various components of joints provide a proper basis for understanding the nature of pathologic lesions to which they are subject and their imaging appearances. This study was designed to correlate MR imaging with a systematic histological study of the normal sacroiliac joint (SIJ), which to our knowledge is not available in the literature.

DESIGN AND PATIENTS

Five male cadavers, aged 20 to 45 years, and seven male and seven female volunteers, aged 23 to 44 years, were investigated with oblique transaxial and coronal MR imaging of the SIJs. A variety of sequences including pre- and post-contrast T1 fat-saturated studies in the volunteers were used. Cryosectioning was performed in six SIJs of the five cadavers and compared with the MR images for the microscopic joint anatomy and assessed for the presence of abnormalities resembling those associated with sacroiliitis.

RESULTS

Throughout the SIJ, the hyaline cartilage of the sacral bone and the proximal third of the hyaline iliac cartilage was strongly attached to the surrounding stabilizing ligaments, forming wide margins of fibrocartilage. In the distal one-third of the joint only, the margins of the iliac joint facet resemble that of a synovial joint, which include an inner capsule with synovial cells. The MR anatomy of the ventral and dorsal aspects of the SIJ was only adequately visualized at oblique transaxial MR imaging. No contrast enhancement occurred in the synovial tissue or in the cartilaginous joint space. The dorsal transition between the proximal 2/3 and distal 1/3 of the cartilaginous joint was at microscopy rich in anatomical and histological variants, including osseous clefts, cartilage and subchondral defects, and vascular connective tissue in the bone marrow. These were all recognized at oblique transaxial MR imaging and in coronal MR sectioning may resemble abnormalities. Otherwise, no erosions, bone marrow abnormalities, bone sclerosis or abnormal contrast enhancement occurred in the normal joints.

CONCLUSIONS

The SIJ should be classified anatomically as a symphysis with some characteristics of a synovial joint being confined to the distal cartilaginous portion at the iliac side. Coronal MR imaging does not allow assessment of normal anatomy, variants or abnormalities of the ventral and dorsal margins of the cartilaginous SIJ.

Imaging of sacroiliitis in early seronegative spondylarthropathy. Assessment of abnormalities by MR in comparison with radiography and CT

PURPOSE

To analyze the type and frequency of abnormalities of the sacroiliac joint (SIJ) in early seronegative spondylarthropathy (SpA) by MR in comparison with CT and radiography, assess the most appropriate MR sequences to be used, and introduce a new way of grading MR abnormalities of the SIJ.

MATERIAL AND METHODS

The SIJs of 41 patients with early SpA (median duration of inflammatory low back pain of 19 months) were evaluated by MR imaging using STIR, T1, T2, and T1 fat saturated (FS) sequences before and after i.v. Gd contrast medium followed by staging of abnormalities. The findings were compared with those obtained by CT and radiography.

RESULTS

MR and CT had equal efficacy superior to radiography in staging of erosions and osseous sclerosis. Only MR allowed visualization and grading of active inflammatory changes in the subchondral bone and surrounding ligaments in addition to bone marrow fatty accumulations. T2-weighted sequences did not contribute to assessment of sacroiliitis.

CONCLUSION

MR of the SIJs is reliable in its visualization of joint erosions in early SpA and allows differentiation between active and chronic sacroiliitis. We recommend the following sequences: semicoronal T1 and both semicoronal and semiaxial STIR. If these images are normal, the examination can be finished; otherwise additional semicoronal T1 FS before and after i.v. contrast has to be performed as well as semiaxial post-contrast T1 FS.

Imaging of sacroiliitis in early seronegative spondylarthropathy. Assessment of abnormalities by MR in comparison with radiography and CT

PURPOSE

To analyze the type and frequency of abnormalities of the sacroiliac joint (SIJ) in early seronegative spondylarthropathy (SpA) by MR in comparison with CT and radiography, assess the most appropriate MR sequences to be used, and introduce a new way of grading MR abnormalities of the SIJ.

MATERIAL AND METHODS

The SIJs of 41 patients with early SpA (median duration of inflammatory low back pain of 19 months) were evaluated by MR imaging using STIR, T1, T2, and T1 fat saturated (FS) sequences before and after i.v. Gd contrast medium followed by staging of abnormalities. The findings were compared with those obtained by CT and radiography.

RESULTS

MR and CT had equal efficacy superior to radiography in staging of erosions and osseous sclerosis. Only MR allowed visualization and grading of active inflammatory changes in the subchondral bone and surrounding ligaments in addition to bone marrow fatty accumulations. T2-weighted sequences did not contribute to assessment of sacroiliitis.

CONCLUSION

MR of the SIJs is reliable in its visualization of joint erosions in early SpA and allows differentiation between active and chronic sacroiliitis. We recommend the following sequences: semicoronal T1 and both semicoronal and semiaxial STIR. If these images are normal, the examination can be finished; otherwise additional semicoronal T1 FS before and after i.v. contrast has to be performed as well as semiaxial post-contrast T1 FS.

[Magnetic resonance imaging in musculoskeletal tuberculosis]

The incidence of tuberculosis in Denmark has increased over the last years. Two cases of primary osteoarticular tuberculosis are described: tuberculous ostitis of the scapula and surrounding soft tissue, and tuberculosis of the elbow. We have emphasized the appearance on magnetic resonance imaging (MRI), as the role of this modality has only been sporadically described for osteoarticular tuberculosis in areas other than the vertebral column. The cases show that MRI can contribute to a more precise determination of the extent of osteoarticular tuberculosis and its soft tissue involvement.