Application Of High Resolution CT Arthrography For Knee Joint Lesions

Research backgroundThe etiology of primary or secondary knee joint osteoarthritis are various, generally includingbone and cartilage degeneration.In addition, the injury of meniscus, anterior cruciate ligament, kneejoint capsule, tibial and fibular collateral ligament are the leading cause of secondaryosteoarthritis.Bone and joint diseases are the important causes of disability, many people will losetheir freedom of movement, serious person need artificial joint replacement to preliminary relieffrom pain.According to the prediction of WHO, China will become one of the countries with themost number of patients with bone and joint disease in the world,it will reach1.5hundred million in2015. The osteoarthritis such as fracture, Osteomalacia, hyperosteogeny are easy to diagnose due tothe high density,they can be diagnosed by X-ray plain,but it is difficult to display the structure ofmeniscus, ligaments,articular cartilage,joint capsule and ligament,the injury is not easy to diagnose.It will further aggravate the burden of knee joint and eventually develop into osteoarthritis anddisability for the misdiagnosis or missed diagnosis.In the past,the commonly used imaging diagnostic methods of the knee joint disease were asfollows. The X-ray iodine solution myelography：it was not worth to popularize for its low resolutionand bad image quality due to overlap with bony structure.CT scan and air contrast：the fracture ofcruciate ligament can be diagnosed, but the reqression and tears of the meniscus were still lack ofability; air contrast was not directly on display the injury of meniscus, it can miss the lighter injuryand appear false positive and false negative. MR scan: it was a noninvasive examination, highresolution of soft tissue, the lesions of meniscus and anterior cruciate ligament showed good, widelyused at present, but there will be appear false positive or false negative, and the diagnosis of imagingwas required professional radiologist, the reading ability of clinician needed relatively higher, it was not conducive to promote,reference and treat; high cost and long scan time were bad for promotionof MR in under-developed region and basic hospital. Arthroscopy: it was the best way of meniscusinjury for both it can check and treat, but somebody have counted that the specificity, sensitivity andaccuracy were similar to MR,it can also appear false positive or false negative, it was not conduciveto popularize and apply for more trauma,complications and blind area, arthroscopy was used onlywhen the symptom was heavier and the patient needed operation treatment.In general, these methodswere limited because of low resolution, overlapping, high false positive,high false negative,high cost,long time and big trauma.Therefore, we considered the possibility of high resolution imaging for knee joint using popularspiral CT and cheap meglumine diatrizoate agent, the purpose was to find an economic, sensitive,intuitive inspection to make up for the above mothods. The principle was with the help of highpermeability and high contrast features of positive contrast agent meglumine diatrizoate, the agentcan diffuse and stay in the fissure of tear or rupture of meniscus, anterior cruciate ligament,it canshow the injury site through the volume scanning of HRCT (0.5mm) and MPR techniques,theobjective was try to early diagnose the lesions of meniscus, anterior cruciate ligament and articularcartilage, moreover,it can make up for the defects without MR machine in under-developed regionand basic hospital and lighten the burden of patients, it has certain scientific significance and clinicalvalue.ObjectiveDirect arthrography was used to study knee joint which were suspected lesions by injectedmeglumine diatrizoate agent and scaned with high resolution CT,analysed the imaging features ofmeniscus, articular cartilage and cruciate ligament, compared with the operation and effect ofconservative treatment, to explore the best puncture site,contrast agent concentration and its value inthe diagnosis of the knee joint disease about HRCTA.MethodsFifty patients with suspected knee joint lesion were injected10ml40%or60%concentrationcompound meglumine diatrizoate injection from suprapatellar bursa(n=35) or knee eye(n=15)，thenunderwent HRCT scaning in shenzhen shajing affiliated hospital of guangzhou medical university between may2010to may2012,the raw data were reconstructed with axial、sagittal、coronal andoblique plane techniques, Analysed the success rate of two puncture site and effect of two kinds ofcontrast agent concentrations,the lesions of knee joint were observed from various angles,comparedwith arthroscopic operation and conservative treatment, to verify the correctness of HRCTA indiagnosis of knee joint disease.ResultsThirty-five cases punctured from suprapatellar bursa were successful at one-time;In15caseswhich punctured from knee eye,11cases were successful at the first time,but4cases needed topuncture from suprapatellar bursa once again.The contrast effect of60%concentration was betterthan40%, The former was good for meniscus, articular cartilage, ligament, meniscus cyst andpopliteal cyst.It was filled with high density meglumine diatrizoate in the knee joint cavity and contrastedstrongly with low density meniscus,articular cartilage and cruciate ligament,the shape of lesions andedge of structure were clear, the lower part of meniscus was horizontal, the upper was arched. Infifty cases,32cases of meniscus were diagnosed as injury or tear,medial meniscus in14cases,lateralmeniscus in18cases,it can see horizontal、vertical and diagonal or curve high density line from theinjured part of meniscus in the imaging of HRCTA,among of32cases,7cases of second degreeinjury,25cases of third degree injury.18cases were diagnosed as articular cartilage injury,articularcartilage thinning,rough surface and partial cartilage defect can be seen;12cases were diagnosed ascruciate ligament injury,abnormal density,abnormal morphology filled with contrast from the injurypart could be seen;8cases were diagnosed as discoid meniscus,the meniscus were broadening andthickening,3cases appeared degeneration,1cases appeared tear;6cases were diagnosed as meniscalcyst,it located on the edge of articular surface,adjacent to meniscus and filled with contrast agent;10cases were diagnosed as popliteal cyst,it filled with contrast and communicated with knee jointcavity;6cases of meniscus injury were performed arthroscopic operation in this group, the finding ofarthroscopic were consistent with the diagnosis of HRCTA; the symptoms were improved in5casesof articular cartilage injury after injected sodium hyaluronate in knee joint cavity.Conclusion Suprapatellar bursa is the better puncture site,60%is the better contrast agentconcentration.HRCTAis an economic、intuitive、highly sensitive imaging method,it has a high valuein the diagnosis of meniscus, articular cartilage,ligament and popliteal fossa cyst lesions,and has animportant reference role in screening before arthroscopy,treatment plan and postoperativeassessment,it is worthy of extension and application in under-developed region and basic hospital.