Detection of uric acid depositing in tophaceous gout using a new dual energy spectral CT technology

Issue title: Clinical Radiology

Article type: Research Article

Authors: Li, Xiaohu | Wang, Xu | Yu, Yonqqiang | Liu, Bin | Cai, Jing | Xia, Li | Luo, Li | Wang, Wanqin | Ding, Qianyun | Zhang, Chao | Wang, Jie

Affiliations: Department of Radiology, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China | Department of Radiology, Zhejiang Cancer Hospital, Hangzhou, Zhejiang, China | Department of Rheumatology, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China | Department of Endocrinology, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China

Note: [] Corresponding authors: Bin Liu, Department of Radiology, The First Affiliated Hospital of Anhui Medical University, No. 218 Jixi Er Rd, Hefei 230022, Anhui, China. Tel.: +86 0551 62922368; Fax: +86 0551 62922368; E-mail: ayfyliubin@126.com. Yongqiang Yu, Department of Radiology, The First Affiliated Hospital of Anhui Medical University, No.218 Jixi Er Rd, Hefei 230022, Anhui, China. Tel.: +86 0551 62923223; Fax: +86 0551 62923223; E-mail: ayfyyuyongqiang@126.com

Abstract: OBJECTIVE: To assess the feasibility and diagnostic value of detecting uric acid depositing among patients with tophaceous gout using a dual energy CT based Gemstone spectral imaging (GSI) technology for qualitative analysis of uric acid. METHODS: Thirty one patients with clinically detectable tophaceous gout and 10 healthy volunteers underwent Discovery CT 750 HD scan with GSI mode. We selected four case groups of tophi, muscles, cortical bone, and cancellous bone. Each has a region of interest (ROI) of 10 mm diameter. We then analyzed and compared the difference of CT imaging spectroscopy quantitative parameters including concentration of uric acid, calcium, and water levels. The univariate analysis of variance and independent samples t-test were applied in data analyses. RESULTS: In case group of tophi base substance, the concentration levels were 1268.8 ± 32.2 mg/cm^3 for uric acid (Ca), 19.4 ± 9.5 mg/cm^3 for calcium (uric acid), 10.8 ± 9.5 mg/cm^3 for calcium (water), and 1171.0 ± 26.8 mg/cm^3 for water (calcium), respectively. In cortical bone case group, the four base substance concentration levels changed to 1333.6 ± 83.8 mg/cm^3, 271.1 ± 85.0 mg/cm^3, 262.6 ± 85.4 mg/cm^3, and 1230.8 ± 77.0 mg/cm^3. In muscles case group, the four base substance concentration levels were 1143.5 ± 15.7 mg/cm^3, 12.3 ± 5.0 mg/cm^3, 4.4 ± 1.9 mg/cm^3, and 1054.1 ± 14.6 mg/cm^3. Finally, in cancellous bone case group, the corresponding base substance concentration became 1070.9 ± 26.4 mg/cm^3, 85.1 ± 46.9 mg/cm^3, 77.4 ± 46.7 mg/cm^3, and 988.0 ± 23.4 mg/cm^3. Except tophi and muscle differences between Calcium (uric acid) concentration and differences in Calcium (water) concentration, which were not significantly different (p> 0.29), the remaining group pairwise comparisons of the parameters were significantly different (p < 0.05). CONCLUSION: Dual-energy spectral CT can detect gout tophi within the peripheral joints of the patients. The quantitative measurement of the tophi concentration provides a new imaging method for quantitatively monitoring clinical outcomes of tophi.

Keywords: Hyperuricemia, tomography, X-ray computed, comparative study

DOI: 10.3233/XST-140444

Journal: Journal of X-Ray Science and Technology, vol. 22, no. 4, pp. 541-549, 2014