[Values of fat saturation sequence in MRI for juvenile arthritis].

OBJECTIVE: To explore the values of fat saturation sequence in MRI for juvenile arthritis.
 Methods: A total of 1 131 cases with juvenile arthritis and 1 601 with symptomatic arthritis were examined by MRI normal T1 weighted imaging (T1WI) and T2 weighted imaging (T2WI) sequence and spectral presaturation attenuatedinversion recovery (SPAIR) T2 fat saturation sequence. All the images were independently evaluated by two senior doctors from the Department of Radiology and the Department of Pediatric Rheumatology and Immunology respectively to confirm the types and degree of pathological changes of joint tissues.
 Results: Among the subjects, 847 patients demonstrated positive in MRI, accounting for 52.9%; 409 patients showed positive in normal sequence, accounting for 48.3%; 816 patients showed positive in fat saturation sequence, accounting for 96.3%. Joint hydrops accounted for 59.5%. Bone marrow edema accounted for 39.7%. The relevant ratio of bone marrow edema, joint hydrops, thickening of synovium and cartilage injuries in fat saturation sequence were higher than that in normal sequence (P<0.05). The relevant ratio of bone erosion in normal sequence was higher than that in fat saturation sequence (P<0.05). However, no significant difference of joint cysts was found between the fat saturation sequence and normal sequence (P<0.05).
 Conclusion: Application of fat saturation sequence by MRI to check juvenile arthritis could obviously improve the positive MRI relevant ratio. In addition, the relevant ratio of the early pathological changes of juvenile arthritis (such as bone marrow edema and joint hydrops) was high, which might provide references for the early diagnosis of juvenile arthritis.