Imaging Study Of CT And MR In Ankylosing Spondylitis

Objective:Ankylosing spondylitis is a mostly common clinical disease of seronegative spondyloarthropathy, which severely affects the quality of patient's life. To evaluate the involvement of sacroiliac joint and its relationship with disease duration,laboratory examination and vertebral osteitis in clinically suspected ankylosing spondylitis patient by means of the CT manifestations of sacroiliac joint and the MR manifestations of spine,offering reliable basis for confirmed diagnosis and early therapy.Materia Is and Methods:Thirty-two patients with clinically suspected ankylosing spondylitis were studied.There were 21 males and 11 females,the age range from 16 to 40 years,with average 25.0±6.6 years. The disease duration ranged from 3 months to 10 years. CT scans of sacroiliac joint and MR scans of thoracolumbar vertebrae of all patients were obtained and respectively recorded the laboratory finding of HLA-B27,CRP,ESR.Sacroiliitis was graded according to the New York criteria. The involvement of extent and activity in vertebral osteitis were studied by Berlin MRI spine score method and Berlin spine activity score method.All patients respectively underwent MSCT of the sacroiliac joint and 3.0-T MR scanner of the thoracic and lumbar vertebra.Statistical analysis was done through the use of SPSS 13.0 statistical package.There was statistically significance (P<0.05)Results:There were 7 cases(21.88%)which was of gradeⅠsacroiliitis,17 cases(53.12%) of gradeⅡ,8cases(25.00%) of gradeⅢ. The severity of sacroiliitis was significantly related to disease duration (P<0.001),but not gender (P>0.05). Sacroiliitis was related to the expression of HLA-B27 (P<0.05),but not CRP and ESR (P> 0.05). All of 64 sacroiliac joints were bilaterally involved,each sacroiliac joint was divided into four quadrants(upper iliac,lower iliac,upper sacral and lower sacral).The cases and erosive rate of each quadrant were 39 of upper iliac quadrant(60.94%),48 of lower iliac quadrant(75.00%),15 of upper sacral quadrant(23.44%),11 of lower sacral quadrant(17.19%),respectively.The severity of the sacroiliac joints was more obvious in the iliac side than in the sacral side,the frequency of the lower iliac quadrant to be highest in both groups.There were 28 cases of thoracic and lumbar vertebral osteitis,8 of the thoracic vertebrae,2 of the lumbar vertebrae,18 of the thoracolumbar vertebrae and 23 of the anterior osteitis,1 of the posterior osteitis,4 of the anterior and posterior osteitis. Vertebral osteitis was found more obvious in the anterior than in the posterior edge.In the involvement Vertebral Unit of AS,there were 40 VU of thoracic vertebra (11.90%),1 of T3/4(2.5%),3 of T5/6(7.5%),2 of T6/7(5.0%),10 of T7/8(25.0%), 4 of T8/9(10.0%),1 of T9/10(2.5%),16 of T10/11(40.0%),3 of T11/12(7.5%).The VU T7/8 and T10/11 were found to be more involved,which respectively account for 25.0% and 40.0% of the total. The VU T10/11 was the highest in all VU involved of thoracic vertebra.The inferior thoracic vertebra was more involved than upper thoracic vertebra. In the involvement Vertebral Unit of AS,there were 26 VU of lumbar vertebra (15.48%),5 of T12/L1 (19.23%),12 of Ll/2 (46.15%),4 of L2/3 (15.38%),2 of L3/4 (7.69%),3 of L4/5 (11.54%). The VU L1/2 was found to be most involved. The upper lumbar vertebra was more involved than inferior lumbar vertebra. There were not statistically significance(P>0.05) between the spine score of vertebral osteitis and involvement degree of sacroiliitis.The spine activity score showed that the involvement extent of vertebral osteitis was more insufficient of 25% of a vertebral unit in early AS patient.Conclusion:1. My study firstly introduces that no obvious correlation is found in the detection of sacroiliitis of grade and vertebral osteitis.There are also no correlation between the involvement of sacroiliitis and the activity of vertebral osteitis. These hint that the thoracic and lumbar vertebra may be involved in early AS and we not only heed sacroiliitis but also can't ignore vertebral osteitis in clinically suspected AS patient2. Vertebral osteitis easily involve the inferior thoracic vertebra and upper lumbar vertebra,it is found more frequently in the anterior edge of the vertebra.,the involvement extent of which is more insufficient of 25% of a vertebral unit in early AS. MRI may definitely present the involvement extent and location of the early vertebral osteitis,in favor of the early treatment and effective evaluation of AS patient. 3. CT can clearly show tiny structure of sacroiliac joint and accuracily present the feature of sacroiliitis in different stages.My study shows that sacroiliitis is found more obvious in the lower iliac side, the severity of which is significantly related to disease duration,but not gender,hint that sacroiliitis aggravates with the disease duration longer,deserves to pay-attention to.4. Middle and juvenile male of clinical symptom with sacroiliitis still diagnose AS,though HLA-B27 gene is negative,final diagnosis mainly depends on imaging examination.