Dual Energy Computed Tomography In Tophaceous Gout

Background and purposeIn recent years, the incidence of gout is on the rise. As people’s livingstandards gradually improve, the incidence of gout is increasing and it has become acommon disease. The increase of serum uric acid values is helpful to thediagnosis of gout. Some patients presenting with asymptomatic hyperuricemia maynot develop gout, and a part of patients’ uric acid values are within the normal rangewhile they are in acute gout. Puncture pumping arthroscopic surgery found that asingle water sodium urate crystal is the gold standard for diagnosis of gout. However,the test is invasive, because when there is less amount of synovial fluid crystallizationand the puncture site is difficult to reach, the test will lead to an increase of falsenegative results, causing atypical cases of difficulty and delaying the best treatmenttime. If we have a method to diagnose gout stone check by noninvasive imaging forthe diagnosis of early gout and no attacks of gout period of diagnosis, we will be ableto change patients’ living habits in advance and havedrug intervention. As a result, wewill improve the gout diagnosis rate, avoid invasive examination, save time anddecrease the occurrence of complications.The purpose of this study:1. using DECT examination in patients to examinegout uric acid salt in the detection characteristics of skeletal muscledeposition.2.using DECT to test urate deposition of urate deposition and quantitative detection of gout volume of limbjoints.Materials and MethodsFrom June2012to June2013,20cases of gout patients had treatment in ourhospital. They were in line with the American Rheumatism Association (ARA)classification criteria. The age of20cases of gout patients are37-82years old,meaning that thay are63±0.3years old on average. The blood uric acid level of15males (75%) and5females’(25%) is302-701mmol/L range.10cases in thecontrol group is the other joint diseases (5cases of psoriatic arthritis,2cases ofrheumatoid arthritis, a vacation gout, one case of pigmented villonodular synovitisand one case of undifferentiated inflammatory arthritis). Patients aged35-80years,meaning57±0.2years old on average, including six males (60%) and4females(40%).This study used second-generation Siemens SOMATOM Definition Flashdual-source CT (SOMATOM Definition Flash Computed tomography). Scan Mode:patient supine. Scan range includes feet, ankles and double knee joint, and then theprone position, scanning hands joints, wrists joints, double elbow. Scan parameters:tube A,140kV/55mA, tube B,80kV/243mA. Collimator0.6mm, reconstructionincrement0.75mm. Scan range of peripheral joints (elbow, wrist, hand, knee, ankleand foot) in all patients. The two sets of data will be transmitted to the workstationby two independent radiologists for diagnosis, and the use of DECT GOUT softwarecan automatically mark whether the urate deposition.Using software SPSS19.0as statistical methods (1) calculate the relationshipbetween the number of DECT proceeds urate deposition and bone, tendons ligamentsAND compare using the t test and χ2analysis to calculate.95%confidence intervalsare bilateral, while p <0.05shows there are differences.(2) DECT urate depositionresulting number and the number of clinical examination compared using pairedWilcoxon signed-rank test, test level α=0.05. When P <0.05, the difference wasstatistically significant.ResultsAfter dual-source CT scan,20cases of gout patients revealed urate deposition on10.8%of the tendons, ligaments and bones of10.3%. Achilles tendon is the most commonly involved one. The Achilles tendon (39.1%), followed by the fibula tendon(18.1%). Tibialis anterior and extensor digitorum longus tendon is less common(7.6-10.3%), other deltoid flexor tendon and plantar tendon are rarely (<5%).Separate urate deposition prevalent is common in the Achilles tendon.After dual-source CT scan,20cases of gout patients were found440uratedeposition, while clinical findings are only111, which means DECT scan revealed aclinical examination four times larger than gout nodules. However, we found no uratedeposition in the10patients with other types of arthritis in the control group. Thetotal volume of urate deposition is0.63cm3-249.13cm3,40.20cm3±0.3cm3onaverage.ConclusionDual-source CT can color display and determine the presence of subclinicalurate deposition. In addition, the program can automatically measure the volume ofurate deposition. Achilles tendon attachment points are the main points of uratedeposition, which indicates that the biomechanical strain tendons or other localfactors may help urate deposition.