Morphological And Functional MRI Study Of The Knee After Anterior Cruciate Ligament Reconstruction Using Autologous Tendon

Chapter 1 MRI findings of knee after anterior cruciate ligament reconstruction:correlation with clinical examinations[Objective] To analyze the MRI findings of the knee after ACL, and explore the correlation of MRI findings and clinical examination.[Methods] Clinical and MRI study were performed on 94 eligible patients with anterior cruciate ligament reconstruction,75 male,19 female,45 left knees and 49 right knees; Patient’s age ranged from 16 to 47 years old In All patients performed knee joint MRI and physical examinations, including Lysholom score, anterior drawer test, Lachman test, pilot-shift test. Philips 1.5 T Intera, Philips 1.5 T Achieva Achieva TX or 3.0 T MR imaging system were used with 8 channel dedicated coil for the knee. Sagittal and coronary images were obtained. Two radiologists analyzed the images independently, including graft signal and continuity, position and dimeter of the bone tunnel, screw and the surrounding bone of the tunnel and articular cavity. Differences of positive rate between the two groups were compared by using Fisher’s exact test. Kappa test for consistency between clinical examination and MR performance.[Results] Lyshlom scores ranged from 67 to 95, an average of 79.3 points. Fifteen knees were instable according to clinical exam,79 cases stable. Abnormal graft signal was seen in 34 cases, abnormal bone tunnel position in 3 cases, abnormal bone tunnel diameter in 23 cases, including 13 cases of femoral tunnel and 10 tibial tunnel; intra-tunnel cyst was seen in 3 cases and all occurred in the tibia bone tunnel. Statistical differences between the two groups. There was a higher positive rate in positive group than negative group with MR sign of bone tunnel position, tunnel enlarge, graft signal and internal fixation.[Conclusions] MR in assessing bone tunnel and graft are related with clinical diagnose about knee stability after anterior cruciate ligament reconstruction, which may provide valuable information for clinical post-operation follow up and second operation.Chapter 2 Diffusion Tensor Imaging of the Anterior Cruciate Ligament Graft After Reconstruction: Reproducibility and DTI MetricsObjectives:To explore the feasibility and reproducibility of diffusion tensor imaging(DTI) and diffusion tractography(DTT) on the anterior cruciate ligament graft after reconstruction and determine the fractional anisotropy(FA) and apparent diffusion coefficient(ADC) values.Methods:Twenty-two patients with ACL reconstruction operation were scanned at 3T clinical MR scanner. The fiber tracking and other post-processing steps were carried out twice by a radiologist on the workstation and repeated by another radiologist. Diffusion tensor metrics of different parts of the grafts were determined with region of interest (ROI)- and fiber tractography (FT)-based measurements and the intra- and inter-observer measurement variances were calculated.Results:Tractography illustrated nicely the 3D courses of the graft in all 22 cases. The mean FA value of the intra-tunnel part was significantly higher than that of the intra-articular part, whereas the mean ADC value of the intra-tunnel part was lower when compared with that of the intra-articular part. According to the two-sided paired samples Student’s t test, the intra- and inter-observer measurements correlated well.Conclusions:DTI and DTT can be used to visualize the ACL grafts, and can provide additional information over standard morphologic MR imaging. The assessment of the ACL graft is of great concern for post-operative rehabilitation training.DTI and DTT can help the surgeons evaluate the ACL grafts quantitatively and intuitionisticly.Rehabilitation training can be given with greater confidence.Chapter 3 Comparative study of CT and MRI in the evaluation after anterior cruciate ligament reconstructionObjective:To compare the application of CT and MRI in the evaluation after anterior cruciate ligament reconstruction, and discuss the clinical application of new imaging technique.Materials and Methods:Fifteen patients with anterior cruciate ligament reconstruction were scanned with spiral CT, routine MRI and MR diffusion tensor imaging,12 male,3 female,22.4years on average. The grafts, tunnels and surrounding structures were observed and scored by an experienced radiologist and and experienced orthopedist specialized in arthroscopy.Results:The bone tunnel,screw and inter-face can be well demonstrated by CT curve planar reconstruction, multiple planar reconstruction can be used to show the contour of the graft and the osterophyte of the inter-condylar notch, volume render technique help realize the observation of the tunnel aperture from any 3D view. MRI can demonstrate the fiber bundle and evaluate it quantitively. There were statistical difference between CT and MRI when evaluating the graft, tunnel aperture, surrounding bone mineral density and other joint structures.Conclusions:CT provided more information than MRI in the observation of tunnel aperture, surrounding bone mineral density, and MRI was more sensitive to the grafts changes. New technique of CT and MRI made post-operative evaluation more intuitive and objective, and could be used in clinical practice.