THU0598 ROLE OF DUAL-ENERGY CT AS A SCREENING TOOL FOR CORONARY GOUT
Authors: Waleed Abdellatif, Brandon Chow, Savvas Nicolaou
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Gout is prevalent in older men and has been demonstrated as independent cardiovascular risk factor. Presence of clinical gout rather than isolated hyperuricemia is related to the increased cardiovascular risk. Dual-Energy CT (DECT) has proven to be of high sensitivity and specificity in detection of monosodium urate (MSU) deposits in joints and soft tissues. <h3>Objectives</h3> Evaluate DECT as a potential screening tool for monosodium urate deposits within the coronary arteries. Calculate prevalence of coronary gout in patients with confirmed tophaceous gout in comparison to asymptomatic control group. <h3>Methods</h3> Cases were retrospectively assigned into two groups. The first (tophaceous gout) group included patients who were referred for DECT gout screening. The inclusion criteria were: males &gt; 50 years of age and clinical diagnosis of tophaceous gout confirmed by DECT. The second (control) group included patients who underwent non-contrast DE Cardiac CT for calcium scoring during the same duration as part of cardiovascular risk workup. Inclusion criteria were males &gt; 50 years of age, no clinical diagnosis of gout and Agatston calcium score less than 400. All DECT scans were done on the same scanner, which was validated and adequately titrated before the start of and during the study. All scans were reviewed by two radiologists with expertise in DECT gout deposits. <h3>Results</h3> Among the 13 cases that met the inclusion criteria for the tophaceous gout group, 11 were positive (84.62%) for coronary MSU deposits. Among the 48 cases that met the inclusion criteria for the control group: 47 were negative and one was positive (2.08%). DECT sensitivity was 84.62% (95% CI: 54.55-98.08%), specificity was 97.92% (95% CI: 88.93- 99.95%), positive predictive ratio was 91.67% (95% CI: 60.94- 98.73%), negative predictive value was 95.92% (95% CI: 86.78- 98.83%) and accuracy was 95.08% (95% CI: 86.29- 98.97%). <h3>Conclusion</h3> Coronary MSU deposits are seen in 84.62% of tophaceous gout patients and in 2.08% of gout-asymptomatic individuals (of the same age and sex group). DECT has high sensitivity, specificity and diagnostic accuracy in detection of MSU coronary deposits and can be used as a feasible, quick, low dose and low risk screening tool to detect coronary gout. DECT cardiac scans should be included in the routine CT gout protocol. Performing CT Calcium score using dual-energy has the added value of coronary gout detection as part of cardiovascular risk assessment and workup. <h3>References</h3> [1] - He, J., Yang, Y., &amp; Peng, D. Q. (2012). Monosodium urate (MSU) crystals increase gout associated coronary heart disease (CHD) risk through the activation of NLRP3 inflammasome. International journal of cardiology, 160(1), 72-73. [2] - Andrés, M., Quintanilla, M. A., Sivera, F., Sánchez‐Payá, J., Pascual, E., Vela, P., &amp; Ruiz‐Nodar, J. M. (2016). Silent monosodium urate crystal deposits are associated with severe coronary calcification in asymptomatic hyperuricemia: an exploratory study. Arthritis &amp; Rheumatology, 68(6), 1531-1539. [3] - Yu, Z., Mao, T., Xu, Y., Li, T., Wang, Y., Gao, F., &amp; Sun, W. (2018). Diagnostic accuracy of dual-energy CT in gout: a systematic review and meta-analysis. Skeletal radiology, 1-7. [4] - Nicolaou, S., Yong-Hing, C. J., Galea-Soler, S., Hou, D. J., Louis, L., &amp; Munk, P. (2010). Dual-energy CT as a potential new diagnostic tool in the management of gout in the acute setting. American Journal of Roentgenology, 194(4), 1072-1078. [5] - Rai, S. K., Aviña-Zubieta, J. A., McCormick, N., De Vera, M. A., Shojania, K., Sayre, E. C., &amp; Choi, H. K. (2017, February). The rising prevalence and incidence of gout in British Columbia, Canada: population-based trends from 2000 to 2012. InSeminars in arthritis and rheumatism (Vol. 46, No. 4, pp. 451-456). WB Saunders. <h3>Disclosure of Interests</h3> Waleed Abdellatif: None declared, Brandon Chow: None declared, Savvas Nicolaou Grant/research support from: The Department of Radiology, Vancouver General Hospital has a Master Research Agreement with Siemens Healthcare, Forcheim, Germany (non-pharmaceutical company).