Evaluating The Diagnosis Value Of Dynamic Mri In Osteoarthritis Of Patellofemoral Joint

Knee osteoarthritis (OA) is a common joint disease increased with aging. OA is one of predominant reason of joint pain in the older age, which affect their living condition. China is an old aging contrary. People more than 60 years old in China would reach 167.14 million by the end of 2009. For young men, knee trauma would increase the risk of OA. So, Correct movement style and effective precaution measure are very important to delay and to prevent the development of OA. Early diagnosis and early treatment could relieve OA and refrain from late stage.Knee is a predominant loading joint of human, which is easy to be hurt. Early diagnosis of OA is focus by researchers. MR characters are non-traumatic, well tissue contrast, multiple planes, multiple sequences, and high resolution obtained from 3D data with superiority than other examination.Due to the complication of knee movement, traditional imaging method could not sufficiently demonstrate the knee. This study flex knee joint at 10, 20, 30, 40, 50, 60 degree separately to obtain dynamic MR knee images. Imaging features of early knee OA were observed. The value of different degree images was assessed. The mechanism of patellofemoral joint OA was discussed. The result of this study would serve as an imaged basis to the clinical treatment of OA, and theory basis to prevent the development of OA and to make sure the safety movement knee angle.Objective: To investigate the value of dynamic magnetic resonance (MR) imaging in detecting the cartilage defect and bone marrow edema like lesion (BMEL) in early patellofemoral OA. To evaluate the dynamic MRI diagnosis value of early patellofemoral OA by obtain the correspondence of cartilage lesions and BMELs under cartilage at 10, 20, 30, 40, 50, 60 degree separately. Methods: Patients volunteers with patella pain were recruited and performed MR examination. A 1.5-T unit (Symphony; Siemens Medical System) with a receive-only surface coil was used. 36 lesions were found in 22 knee OA (9 male, 13 female; age range, 31~69 years, mean 47 years). 13 BMELs were located at both patella and femoral condyle. 5 BMELs only located at patella. 4 BMELs only located at femoral condyle. T1WI-SE,TSE-Pb,T1WI VIBE water excited sagital sequence were obtain in each patients. Cartilage defect grading was obtained. Quadriceps muscle was relax during the examination. TSE-Pd sequences were obtained with 10 minutes interval during knee flexed at 10, 20, 30, 40, 50, 60 degree separately.The location, size of BMELs and maximum correspondence lesion at patella and femoral condyle were observed. The angle suffered most trauma were determined. All the imaging data were read by 3 MR doctors with more than 10 years muscloskeletal experience. Consensus was reached of correspondence angle in all cases after standards unification.T-test was used in comparing the grading of cartilage between(0°-20°)group and(30°-50°)group. All of the statistical computations were processed using SPSS 13.0. The significance level was 0.05.Result: T1WI,TSE-PD-FS and T1WI-VIBE sequence were evaluated using a 4 scare level. T1WI-VIBE sequence was optimum in cartilage with highest score (3.64±0.49). Highest score of BMELs, menisci, ligament and joint effusion were found at TSE-PD-FS sequence. The normal bone was well imaged at T1WI with a score of 3.95±0.21. Statistic significance was found in the result.. Four abnormal signal of cartilage in T2WI sequence were found at patellofemoral joint. 20 lesion show localized thinner, while 12 localized defect. 36 BMELs were found at 22 patellofemoral joint. 4 located at tibia condyle. The minimum size of BMELs was 0.51cm, while the maximum size was 2.52cm. One case with meniscus tear, while 10 cases with degeneration menisci. Joint effusion was found at 5 cases. Correspondence BMELs of patellofemoral joint were predominant at 40 degree (ranged from 30 to 60 degree) with knee flex position. No correspondence BMELs or cartilage defect of patellofemoral joint were found at less than 30 degrees. The grading of cartilage between(0°-20°)group was lower than(30°-50°)group (p<0.05).Conclusion: Dynamic MRI with multiple knee flex angle is a safety examination method, with T1WI VIBE served as an optimum sequence. It is easy to be injured during the knee moving from 30°-50°. Knee movement with degree less than 30°is an efficient method to prevent patellofemoral OA.