The Diagnostic Value Of T2Mapping Of Knee Osteoarthritis Cartilage Injury

Objective:To investigate the femoral and tibial cartilage T2value differencesbetween different degrees of osteoarthritis (OA) patients compared withhealthy subjects, and discuss the value of using the knee cartilage T2values as a diagnostic method of chinese people with osteoarthritis.Methods:Perform MRI on53patients that were diagnosed as osteoarthritisclinically.The clinical diagnosis of osteoarthritis was based on theChinese Medical Association in2007promulgated Rheumatology,namely knee osteoarthritis diagnostic criteria:①r epeated knee paininthe past one month;②X-ray film (standing or weight-bearing position)shows joint space narrowing, bone sclerosis and (or) cystic degeneration,osteophytes in the subchondral articular margin;③s ynovial fluidis (atleast twice) clear, viscous, WBC≤2000/ml;④in elderly patients (≥38 years old);⑤morning stiffness≤3min;⑥bone fricative (flu) is active.Or to meet①+②or①+③+⑤+⑥o r①+④+⑤+⑥can bediagnosed as osteoarthritis. All patients enrolled had knee painsymptoms, activity limitation.60subjects was performed knee MRI (TRUE fisp and T2mapping)scan.In accordance with the International Cartilage Repair (ICRS)standards and TRUE fisp image,two radiologists graded the subjects into3groups according to the damage of the cartilage. ICRS articularcartilage injury criteria divided the cartilage injuries into five levels:0,nosignificant articular cartilage morphology and signal changes,smoothsurface;class Ⅰ,cartilage signal abnormalities,but normal cartilagemorphology;class Ⅱ mild cartilage surface irregularities and/orlocalized cartilage defects depth of less than50%of the total layerthickness;class Ⅲ,severe cartilage surface irregularities, cartilagedefect depth of more than50%of the total layer thickness,but notinvolving the full thickness cartilage;class Ⅳ,the whole layerexfoliation,defect,exposed subchondral bone with or withoutsubchondral bone signal change.According to classification results, thesubjects were divided into three groups: mild OA group, severe OAgroup and the control group. Among them, the mild OA groupcorresponds to grade I and II of the ICRS standard, and severe OA group corresponds tograde III and IV of the ICRS standard,thecorresponding control group corresponds grade0of the ICRSstandard.After the knee MRI scan, images,which have severe motionartifacts, of five patients,do not meet the inclusion criteria.Andultimately55subjects were included into the groups:20subjects wereincluded into the mild OA group,including17females and3males;28subjects were included into the severe OA group,including14femalesand14males;7subjects were included into the control group,includingincluding three females and four males.Use3.0T MRI (MAGNETOM Skyra system, Siemens) performingthe knee scan for subjects, using a dedicated knee coil, supine position,foot-advanced, knee flexion of about20°.The femur and tibial cartilage of the subjects were divided into fourareas on obtained T2pseudo-color images, namely the medial femoralcartilage area, the lateral femoral cartilage area, medial tibial cartilagearea and lateral tibial cartilage area. Analyze the T2relaxation time ofthe Femur and tibial areas of the three groups.Results:1.T2values of the full-thickness femur and tibial medial cartilageof mild and severe OA subjects increased significantly compared withthe healthy control group.2In addition to the lateral tibial cartilage area,T2values of the restof the cartilage area of mild and severe OA subjects increased significantly, compared with healthy subjects group.3Average T2values have no significant differences between mildand severe OA.Conclusions:1.T2value of the knee cartilage changed in early form of the kneeosteoarthritis, suggesting that T2mapping imaging can be used as anearly diagnostic criteria for the diagnosis of osteoarthritis.2.Distribution of the T2value of the articular cartilage has a spatialdistribution feature,suggesting that the T2value of the cartilage may berelevant with the burden of articular.3.T2values of different levels of osteoarthritis has no significantdifference, suggesting that T2values of the cartilage can not be used asthe criteria of the stages of osteoarthritis.