| [Objective]1. To use the findings of arthroscopy as the standard reference .evaluate the different sigal intensity and value of MRI for the diagnosis of the injuried menisci comparatively.Investigate the standard of MRI diagnosing of discoid menisci and the valse of three MRI signs in diagnosing the bucked-handle tears (BHT) of menisci of the knee .2. To assess the diagnosis valuation of MR imaging of both normal and injuried cruciate ligaments of knee.[materials and methods]132 cases with meniscus (including 16 cases with discoid meniscus) and 103 cases with cruciate ligaments which had undergone both arthroscopy and MRI were reviewed retrospectively. The study included 20 cases with normal lateral meniscus and 30 cases with normal cruciate ligaments .1. According to the different signal intensity of the MRI diagnosis, 132 cases with injuried meniscus were divided into three degree.which were divided into six configurations:horizontal,oblique,longitudinal,bucket-handle,shape of brush and separate of menisci-arthrosispurse depending on the correlation of tears and direction of menisci. Meanwhile, 132 cases with injuried meniscus were classified into anterior horn body of meniscus and posterior horn depending on the locationof injury. Calculate sensitive,specificity and accuracy of meniscus tears respectively.2. To msasure the width and thickness of 14 cases with lateral discoid meniscus and 20 cases with lateral normal meniscus on sagittal and coronal MR images, calculate the remarkable differences between discoid and norml meniscus.3. Each knee joint was analyzed for three signs:(l) an abnormal circumferential meniscus sign;(2) a double posterior cruciate ligament sign;(3) a double anterior horn sign. Sensitive,specificity,accuracy,positive and negative predictive values for diagnosing BHT of menisci were calculated for the presence of each individual sign.4. 103 cases of ACL were classified into normal group,partial injuried group and complete injuried group.depending on the degrees of injuried menisis. On sagittal MR image, To measure the angle formed by the intersection between the anterior cruciate ligaments and the medial tibial plateau(AT angle),posterior cruciate ligment angle, posterior cruciate ligment curvature index .respectively. Compared with their findings between two groups,calculate the significant differences between two groups.Analyse the MRI findings of both normal and injuried cruciate ligaments.5. All patients had undergone both MRI and arthroscopy of the knee, using the findings of arthroscopy as the referent standard.Analysis the feature of cruciate ligaments.6. All these data were analyzed with analysis of variance, x~2 test and t test inthe study.remarkable standard is: α =0.05.[Results] 1. There were grade I in 18cases, grade II in 55 cases, grade III in 59 cases.Compared with the findings of arthroscopy ,the sensitive,specificity and accuracy of diagnosis of MRI were 91.2%,92.0%and 91.7% respectively. The tear of posterior horn of menisci was more common than anterior horn or body . There was no significant difference between anterior horn and posterior horn (p>0.05). 2. 16 cases with discoid meniscus were identified by arthroscopy, including 14 cases with lateral discoid meniscus. On coronal images, the average width inmid-body of 14 cases with lateral discoid meniscus was 22.59 ± 6.30mm, the average width m mid-body of 20 cases with lateral normal meniscus was 10.98±2.01 mm, there was significant difference between the width of discoid meniscusand normal meniscus(p<0.05). On saggital images, bow tie sign was informed by the continuity of anterior and posterior horn of the discoid meniscus, which could be demonstrated over three sections, while there were two sections in normal menisci.3. 13 cases with BHT were identified by arthroscopy ,there were three images of MRI. Their sensitivities ranged between 20.0% and 60.0%,specificities ranged between93.2% and 97.7%, and accuracy ranged between 78.0% and 86.4% respectively. Positive and negative predictive values ranged between 66.67% and 81.80%, and between 78.2% and 87.5% respectively.4. On sagittal hwiges, AT angle of normal ACL was 55.87±4.90, PCL angle was 117.30±5.72, PCL curvature index was 4.45±0.44,respectively. AT angle of partial injuried ACL was 57.37±3.80, PCL angle was 115.47±5.76, PCL index was 4.33±0.40, respectively. AT angle of complete injuried ACL was 41.00±4.57, PCL angle was 100.33±5.88, PCL index was 3.50±0.32,respectively. There wasno significant difference between three indexs of partial injuried ACL and normal ACL(p>0.05); there was significant difference between these indexs of complete injuried ACL and normal ACL(p<0.05); there was significant difference between these indexs of complete injuried ACL and partial injuried ACL(p<0.05), respectively.On MRI,the feature of normal ACL and PCL presented as low signal in any sequence the injury of partial ACL and PCL displayed partial high signal intersity thickening of the ligament,the injury of complete ACLand PCL displayed discontinuity, swelling, thickening and disappearation of normal anatomy. [Conclusions]1. MRI can display the anatomy of menisci and diagnose intersection signal changes of menisis accurasly and make grade of diagnosis.2. The characteristic MRI appearance of discoid meniscus is a meniscus which is significantly larger and thicker than a normal one, meanwhile could be demonstrated on three or more contiguous 5 mm sections in all discoid menisci and be easily identified on MRI. Meniscal tears and degeneration are very common findings in discoid menisci.3. BHT of menisci may have many signs on MRI,there were different capability in diagnosing variety MRI signs.4. Complete ACL and PCL have conspicuous direct signs and indirect signs on MRLwhich could be easily diagnosed. However,indirect signs of diagnosing injuried ACL on MRI is important.The diagnosis of partial ACL tear was unconspicuous direct signs and few indirect signs,which may gave rise to MRI false-positivsimd false-negative. It is necessary to analize and value synthesily0... |
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