Iodine Parameters in Triple-Bolus Dual-Energy CT Correlate With Perfusion CT Biomarkers of Angiogenesis in Renal Cell Carcinoma.

Abstract

<b>OBJECTIVE.</b> The purpose of this study is to determine the degree of the relationship between perfusion CT (PCT) parameters and iodine concentration metrics derived from triple-bolus dual-energy CT (DECT) and to compare the radiation dose delivered. <b>SUBJECTS AND METHODS.</b> This single-center prospective study was conducted from October 2015 to September 2017. Twenty-three consenting adults (15 men and eight women; mean [± SD] age, 56 ± 13 years [range, 25-78 years]) with renal cell carcinomas underwent consecutive PCT and triple-bolus DECT examinations. Triple-bolus DECT consisted of synchronous corticomedullary, nephrographic, and delayed phase scans acquired using a dual-source DECT scanner. Two readers independently analyzed blood flow, blood volume, and permeability, as measured by PCT, and iodine density and iodine ratio, as measured by triple-bolus DECT. Size-specific dose estimates were calculated for both groups. <b>RESULTS.</b> Interreader agreement was good for permeability (intraclass correlation coefficient [ICC] =.812) and blood flow (ICC = 0.849) and excellent for blood volume (ICC = 0.956), iodine density (ICC = 0.961), and iodine ratio (ICC = 0.956). Very strong positive correlations were found between blood volume and iodine density (<i>p</i> < 0.001) and between blood volume and iodine ratio (<i>p</i> < 0.001). Strong positive correlations were found between blood flow and iodine density (<i>p</i> < 0.001) and between blood flow and iodine ratio (<i>p</i> < 0.001). The correlations between permeability and iodine density (<i>p</i> = 0.01) and between permeability and iodine ratio (<i>p</i> = 0.02) were moderate. The mean size-specific dose estimate of triple-bolus DECT was approximately 15 times lower than that of PCT (<i>p</i> < 0.001). <b>CONCLUSION.</b> Quantitative iodine metrics derived from triple-bolus DECT showed significant correlation with CT parameters in renal cell carcinoma, with a significantly lower radiation dose.