OBJECTIVE: To diagnoze active ankylosing spondylitis (AAS) by magnetic resonance imaging (MRI). METHODS: MRI of the sacroiliac joint (SIJ) was performed on 48 patients who were clinically diagnosed as probable AS without radiologic evidence of sacroiliitis. Among them 21 were diagnozed as active sacroiliitis with MRI, whose examination was terminated; 27 whose MRI of SIJ did not diagnoze as active sacroiliitis were performed MRI in the thoracic spine. The diagnostic criteria of MRI for AAS of SIJ and/or the thoracic spine were fomulated by consulting documents. The definite diagnosis of AAS was finally made after follow-up for half a year. The sensitivity and specificity of the MRI of SIJ and/or MRI of thoracic spine were assessed. RESULTS: In the 48 patients without radiologic evidence of sacroiliitis, 38 were finally diagnosed as AAS, with established consensus criteria as reference standard. The sensitivity and specificity of the MRI of SIJ were 52.6% and 90.0%, and for the MRI of SIJ and/or the MRI of the thoracic spine 76.3% and 90.0%, respectively. CONCLUSION Clinically probable AS without MRI evidence of sacroiliitis, MRI of the thoracic spine can increase the sensitivity of AAS diagnosis.
Adolescent ; Adult ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Radiography ; Sacroiliac Joint ; diagnostic imaging ; pathology ; Spondylitis, Ankylosing ; diagnosis ; Thoracic Vertebrae ; pathology ; Young Adult

This study was to clarify whether Behcet's disease (BD) could be classified into the spondyloarthropathy (SpA) complex. It was undertaken on 58 patients with BD (BD group), 56 patients with SpA (SpA group), and 3 patients who concurrently satisfied the criteria for BD and SpA (BDSpA group). The clinical parameters and known susceptible HLA antigens were compared between BD group and SpA group. In addition, 3 patients in BDSpA group were reviewed. The prevalence of definitive sacroiliitis (SI) in BD group and SpA group was 46.4% and 5.2%, respectively. However, none had a definitive SI in healthy controls. Enthesitis was observed in 3.4% of BD group and in 50% of SpA group. The patterns of eye involvement were different between these two groups. HLA-B27 was negative in all 49 patients of BD group, whereas it was positive in 67.9% of SpA group. The prevalence of HLA-B51 was 51.7% in BD group, and that in SpA group was 21.4%. One patient in BDSpA group was considered to have concurrent BD and ankylosing spondylitis (AS). Another patient was closer to AS, and the third to BD. Conclusively, it seems that BD could not be classified into the SpA complex.
Adult ; Behcet Syndrome/*classification/immunology/pathology ; Eye/pathology ; Female ; HLA-B Antigens/analysis/immunology ; HLA-B27 Antigen/analysis/immunology ; Humans ; Lumbar Vertebrae/pathology/radiography ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Pelvis ; Radioactive Tracers ; Sacroiliac Joint/pathology/radiography ; *Spondylarthritis/immunology/pathology ; Tomography, Emission-Computed, Single-Photon