| Anterior Cruciate ligament(ACL) is an important structure which resists anterior tibial translational and tibil internal rotation in knee joint. ACL rupture is a common sports injury which can lead to knee instability, decreased muscle strength, poor knee-related life quality in short term, and an increased risk of knee osteoarthritis in clinical observation. Most ACL tear patients will undergo ACL reconstruction surgery to restore their knee stability, which need accurate assessment of injured ACL before preoperatively. Magnetic resonance imaging(MRI) is the optimal method for the diagnosis of ACL rupture with highly accurate value in the native ACL evaluation and especially in the completely ACL tear. However, the sensitivity and specificity of MRI for the partial ACL tear is low, as well as low quality to visualize bony structure in ACL insertion avulsion fracture. ACL tear patients with metal implants cannot take the MRI by its contraindication; MRI is a high-cost examination to some people and will take a long time compared with other medical examinations. According to this, a new method of ACL visualization is needed.Recently, three-dimensional computed tomography(3D-CT) technique has been developed, based on its superiority of evaluating various soft tissues such as the bronchus, the vasculature, the gastrointestinal tract, and the bladder, and is also valuable for the detection of the relationship between soft tissues and bones, more importantly, 3D-CTscan is a inexpensive, safe and efficient examination which also can be taken in those patients with metal implants. 3D-CT technique can allow visualization of the main knee ligaments in 3D form. But there is still no report showed the ACL view by using 3D-CT.In present study, we attempted to obtain clearly view of native ACL by using dual-energy computed tomography(DE-CT) and compared them with the arthroscopic findings, meanwhile to discuss the possible clinical benefits of 3D-CT on native ACL by using DE-CT.Part 1. Imaging of normal anterior cruciate ligamentObjective: In this research attempted to use dual energy CT in imaging of normal anterior cruciate ligament of the knee joint.Methods: In this study, dual energy CT scanning were taken in a total of 37 subjects with supine position and double knees flexed at 90 degrees, the normal anterior cruciate ligament volume rendering image were collected and the image clarity scores were assessment, then the ligament morphology and ligament insertion points were measured.Results: On dual energy CT imaging of anterior cruciate ligament with coronal and sagittal planes screenshot evaluation, the anterior cruciate ligament could Image clarity, the clarity scores were 9.7838 + 0.8542 points; most of the anterior cruciate ligament could be distinguished from its double bundle, and partial ligaments were single bundle; The measurement of anterior cruciate ligament with an average length of 28.5 mm, 7.1 mm, 3.6 mm thick; with the Bernard four grid method, the mean position of the femoral axis was 31%, and the Y axis was 33%; with the Lorenz method, the mean axis of the X axis was 48%, and the mean position of the Y axis was 37%.Conclusion: The dual energy CT can be used for imaging the normal anterior cruciate ligament of the knee joint, and it also can be used to measure the shape of the ligament and the mark center of the natural ligament footprint.Part 2. Imaging of injured anterior cruciate ligamentObjective: This research attempted to use dual energy CT in imaging of injured anterior cruciate ligament of the knee joint.Methods: In this study, a total of 83 subjects with supine position and double knees flexed at 90 degrees were taken dual energy CT scanning, collected the injured anterior cruciate ligament volume rendering image and assessment the image clarity scores, then the image of the ligament remnants were observed and compared with arthroscopic findings.Results: The injured anterior cruciate ligament cannot be clearly visualized with the dual energy CT scan. The score of the injured ligament were 2.2432 + 2.6077 points and had a significant difference with the normal anterior cruciate ligament imaging resolution(P=0.000). The anterior cruciate ligament remnants morphology by dual energy CT 3D were matched the arthroscopic findings.Conclusion: Injured anterior cruciate ligament cannot visualized clearly by dual energy CT. The anterior cruciate ligament remnants can be observed by dual energy CT imaging, and the morphology were matched the arthroscopic findings.Part 3. Application of dual energy CT in the diagnosis of anterior cruciate ligament injuryObjective: To explore the diagnostic value of dual energy CT imaging in the diagnosis of anterior cruciate ligament injury.Methods: In this study, a total of 37 patients with single knee suspected anterior cruciate ligament injury patients were taken dual energy CT scanning and compared with the arthroscopic findings, evaluated the diagnostic value of injured anterior Cruciate ligament by dual energy CT. The evaluating index was the sensitivity, specificity, diagnostic accurate rate, positive likelihood ratio and Youden index.Results: Using dual energy CT for auxiliary diagnosis of anterior cruciate ligament injury patients, its sensitivity was 80.55%, specificity was 97.37%, the diagnostic accuracy rate was 89.19%, the positive likelihood ratio was 30.63, and Youden index was0.78.Conclusion: The dual energy CT can be used to diagnose the patients with anterior cruciate ligament injury. The diagnostic value was high and the results were reliable. The dual energy CT can be used as an auxiliary diagnostic test for the anterior cruciate ligament injury. |
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