Dual-energy CT Study Of Gouty Arthritis In The Knee

OBJECTIVE:To examine the frequency of monosodium urate(MSU)crystal deposition in knee joint using dual-energy CT(DECT)and measure the volume of MSU crystallization and the volume of bone destruction,to explore the correlation between the volume of MSU crystallization and tendon / ligament damage and bone destruction.MATERIALS AND METHODS:Fifty-seven patients with gout had DECT scanning of both knees,114 knee joints in all were observed by two experienced radiologist independently.The sites of MSU crystal deposition were categorized into groups of intraosseous,intraarticular and soft tissue in order to investigated,the soft tissue MSU crystal deposition were divided into ligament and tendon groups.The MSU crystallized parts of the knee joint with bone destruction were divided into intraosseous group and no-intraosseous group,the volume of bone destructionand the volume of MSU crystallized in this two groups of were measured,and two volumes of each group were analyzed.RESULTS:1.Of the 57 study subjects,MSU crystal deposition was observed in 139 tendons and 152 ligaments,the MSU crystal deposition were showed at the popliteus tendon(32.44%),followed by the quadriceps tendon(25.9%)in the group of tendon.In the group of ligament,the posterior cruciate ligament was the most commonly involved(36.18%),followed by the anterior cruciate ligament(23.03%).2.Gout duration with the total MSU volume and the total number of tendon / ligament involvement has a weak correlation(P=0.001-0.003,r=0.332-0.388),it's no correlation with the volume of bone destruction.The correlation between age,single serum uric acid level with MSU volume,bone destruction volume,and the number of tendon / ligament involvement were not statistically significant.3.The total volume of MSU crystal was positively correlated with the total volume of bone destruction(r=0.685,P=0.000).There was a statistical difference between the bone destruction volume and the MSU volume in the intraosseous group and the no-intraosseous group(P=0.014-0.005),the bone destruction volume and the MSU crystal volume of the former were both larger than the latter.4.The correlation between MSU volume and the bone destruction volume of the intraosseous group has a medium connection(r=0.575,P=0.003),there was no correlation in the no-intraosseous group(r=0.159,P=0.480).CONCLUSION:The common tendons of MSU crystal in the knee joint are poplitealtendon and quadriceps tendon,the frequently deposited ligaments are posterior cruciate ligaments and anterior cruciate ligaments,that may be related to the biological stress and anatomical characteristics of the knee joint.The position of MSU crystal in the knee is related to bone destruction,especially when the knee exists intraosseous MSU crystal,which indicates that the intraosseous MSU crystal has an important impact in the formation of bone destruction.The total volume of MSU in the knee joint has a strong correlation with the total volume of bone destruction,it shows that the size of the MSU crystal is related to the damage of the joint structure,which reflect the importance of reducing uric acid and reducing the volume of MSU crystal.