雙能量電腦斷層掃描發現膝關節韌帶尿酸結晶沉積之高盛行率

Dual-energy computerized tomography reveals high prevalence of monosodium urate deposition in knee tendons and ligaments of gout patients

Objective: To apply dual-energy computerized tomography (DECT) to assess the distribution ofmonosodium urate (MSU) crystal deposition in the limbs of patients with gouty arthritis, focus especiallyon tendons and ligaments.Method: The study cohort comprised 40 patients from Changhua Christian Hospital who were diagnosedwith gouty arthritis according to the 1977 American College of Rheumatology classification criteria of goutbetween September 2014 and June 2016. All received DECT scans of each limb and MSU distributions inthose with positive findings were analyzed.Results: Fourteen patients had negative DECT results and the limb distribution of MSU crystals wasanalyzed in 26, who included 22 males and four females, with mean age of 58.9±16.4 years. Their meanserum creatinine level was 1.2±0.5 mg/dL, mean uric acid concentration 7.4±2.1 mg/dL, and mean totalMSU crystal volume was 5.2±12.7 mm3.The prevalence of MSU deposits in knees (84.6%) was almostas high as ankles/feet (88.4%) in general joint regions. In the detailed structure, the most common MSUdeposition site was the first metatarsophalangeal joint (76.9%), followed by tarsal joint (46.2%) and ankle(57.7%); the highest ranked prevalence in tendons and ligaments were Achilles tendon (38.5%), quadricepstendon (34.6%), and patellar ligament (34.6%).Conclusion: In addition to bone, tendons and ligaments were also highly affected by MSU deposition,with comparably high prevalence of MSU deposits in knee and ankle/foot joints. DECT can identify MSUcrystal deposition that is otherwise difficult to detect by physical examination of tophi when cliniciansdiagnose gout or evaluate severity in chronic disease. 目的：探討慢性痛風病人使用雙能量電腦斷層掃描四肢尿酸結晶的分佈，尤其是韌帶肌腱等軟組織。方法：蒐集2014年9月至2016年6月期間符合1977年ACR診斷標準，並於彰化基督教醫院治療追蹤的痛風患者40人。所有病人皆以雙能量電腦斷層掃描檢查四肢關節，其中陽性結果者納入分析。結果：所有篩檢的病人中，14位檢查結果為陰性，26位納入尿酸結晶分布部位的分析，其中22位男性而4位女性，平均年齡58.9±16.4歲。此群病人的平均血清肌酐值1.2±0.5 mg／dL，平均尿酸值7.4±2.1 mg／dL，平均每人之尿酸結晶沉積總體積5.2±12.7 mm3。就關節區域而言，尿酸結晶分佈於膝關節的盛行率（84.6%）與足踝關節（88.4%）相差無幾。以細部小關節來看，常見沉積位置是第一蹠趾關節（76.9%），然後是足跗關節（46.2%）和足踝關節（57.7%）。尿酸結晶沉積在肌腱韌帶方面以跟腱最多（38.5%），股四頭肌腱（34.6%）和髕韌帶（34.6%）次之。結論：本研究中，我們發現尿酸結晶沉積於骨骼之外，肌腱韌帶也是易受侵犯的部位，這現象可解釋為何尿酸結晶沉積於膝關節和足踝關節之盛行率相當。雙能量電腦斷層為理學檢查難以發現的尿酸結晶提供了很好的幫助，協助臨床醫師診斷痛風和評估慢性痛風的嚴重度。