Magentic Resonance Imaging Application For Detection Of Early Sacroiliitis In Ankylosing Spondylitis

Involvement of the sacroiliac joints (SIJ) is a major and characteristic feature of the ankylosing spondylitis (AS). In 99 % of the patients with AS initial abnormal findings affect the sacroiliac joints. The radiographic changes required for diagnosing AS occur as late as 6 - 7 years after the onset of clinical symptoms. MRI of the sacroiliac joints reliably demonstrates both chronic inflammatory changes (erosions, sclerotic changes, bone bridges) and acute inflammatory changes (synovitis, capsulitis, osteitis) and allows for grading the chronicity and acuity of such changes. Since early inflammatory changes of the sacroiliac joints in AS are demonstrated by MRI before they become apparent on radiographs, and thereby the diagnostic gap could be closed, the early use of MRI for diagnostic and follow-up is commendable, when new therapeutical options like the so-called "biologicals" are employed.we studyed the role of MR Imaging in diagnosis of early sacroiliitis accompaning AS in three aspects.①To assess the diagnostic value of magnetic resonance imaging (MRI) for early stage sacroiliitis of ankylosing spondylitis (AS) . Methods: MR exams of the sacroiliac joints were performed in thirty-two patients with clinically diagnosed early ankylosing spondylitis (AS) and 20 volunteers,and the MR features of these two groups were compared, to determine the MR imaging appearance of the sacroiliac joint when normal and in sacroiliitis. Results:of 32 patients ,29 cases had bone marrow edema, 15 cases had synovial cartilage abnomalitis ,15 cases had bone erosions,6 cases had osteosclerosis,and 5 had bone marrow fatty deposition.of the 20 controls, bone marrow edema in 6, bone marrow fatty deposition in 5, osteosclerosis in 3,and abnormal cartilage signal intensity in 1,but none had showed bone erosions, there were significant differences between these two groups in detecting rates of MR features (P < 0.01), and there were some features in these MR signs.Conclusion: MR imaging can detect sacroiliac joint abnormalities with some false positive rates, MRI is very useful for examining the sacroiliac joints in ankylosing spondylitis in early stage , particularly when results of other imaging techniques are inconclusive.(2)To analyze the correlation between a MRI scoring system (SPARCC) of the sacroiliitis in early Ankylosing Spondylitis (AS) and clinical and laboratory parameters.Methods: 39 patients with a median age of 21.5 yr and a median duration of inflammatory low back pain of 9.5 months were included. They all fulfilled the modified NEW YOUK criteria for AS (0-III) .According to active score (BASDAI), we defined 3 levels (group) of disease activity. The patients were examined by MRI of the SIJs, The severity of activity of SIJs inflammation was evaluated using SPARCC score, and biochemical tests(ESRXRP), Each item was compared among these three groups.Results: There were significant differences among these three groups in SPARCC score (P < 0.05 ) . There were no significant differences among these three groups in ESR and CRP (P >0.05) . Spearman correlation coefficients between SPARCC score and BASDAI score were rs=0. 50, P<0. 05.and between SPARCC score and ESR, CRP were 0.25 and 0.30, P>0.05. Conclusion : It is concluded that MRI was able to detect early and inflammatory changes of the SIJs, SPARCC score was positively correlated with the severity of BASDAI. There was no correlation between the SPARCC score and ESR, CRP.③to compare magnetic resonance imaging (MRI)findings and scoring difference with spiral CT for assessing the sacroiliitis accompanying ankylosing spondylitis(AS).Methods: 42 patients with clinically verified ankylosing spondylitis(AS) were examined with spiral CT using isotropic parameters,and the oblique coronal and oblique axial images were reconstructed, and MRI (1.5T) SE: T1W1 , FS-T2W1, FS-T1WIand 3D-FLASH sequences were used. The images were evaluated by two independent radiologists. The cases were graded and statistical analyzed.Results: The number of detected lesions< II grade was significantly higher with MRI than with spiral CT (17: 7), (P <0.05) , for lesions≥ IIgrade without significant differences (P>0.05) . MRI was equal to spiral CT for lesions≥ II grade, and MRI allows evaluation and gradation of early active inflammatory changes.Conclusions: MRI was superior to spiral CT for lesions < II grade,and was able to detect lesions of all grades, especially on early stage.