cad a22 4500 551414448 20190501043420.0 cr unu---uuuuu 181214e20190501xx s 000 0 eng 10.1016/j.acra.2018.08.008 doi (ZORA)oai:www.zora.uzh.ch:159304 610 ddc 30269958 pmid Can Realistic Liver Tissue Surrogates Accurately Quantify the Impact of Reduced-kV Imaging on Attenuation and Contrast of Parenchyma and Lesions? [Elektronische Daten] [Andre Euler, Justin Solomon, Paul F FitzGerald, Ehsan Samei, Rendon C Nelson] closedAccess eu-repo RATIONALE AND OBJECTIVES To assess if a liquid tissue surrogate for the liver (LTSL) can emulate contrast-enhanced liver parenchyma and lesions and quantify the impact of reduced-kV imaging as a function of lesion contrast, phase of enhancement, and phantom size. MATERIALS AND METHODS First, CT attenuation of LTSL- and water-iodine solutions were measured as a function of iodine concentration and tube potential. For each solution, the iodine concentration was determined to emulate liver parenchyma at 120kV. CT attenuation for both solutions was predicted for different tube potentials and compared to published patient data. Second, liver parenchyma in late arterial phase (LA: +92 HU at 120 kV) and portal venous phase (PV: +112 HU at 120 kV) was emulated using LTSL-iodine and a two-size phantom. Fourteen setups of hyper- and hypoattenuating lesions (lesion-to-parenchyma contrast (C) = -50 to +50HU) were created. Each combination of C, phase, and size was imaged at 80, 100, 120, and 140kV at constant radiation dose. CT attenuation, C, and lesion-to-parenchyma contrast-to-noise ratio (CNR) were assessed and compared to a theoretical model. RESULTS LTSL-iodine more accurately emulated the CT attenuation of liver parenchyma across different tube potentials compared to water-iodine solutions. The theoretical model was confirmed by the empirical measurements using LTSL-iodine solutions: attenuation, C, and CNR increased when the tube potential decreased (p < 0.001). This trend was independent of lesion contrast, phase, and size. The absolute improvement in C and CNR, however, was inversely related to the magnitude of C at 140kV. CONCLUSION LTSL accurately emulated the energy-dependent CT attenuation characteristics of contrast-enhanced liver parenchyma and lesions. The relative improvement in C and CNR by applying reduced-kV imaging was independent of lesion contrast, phase, and size while the absolute improvement decreased for low-contrast lesions. Clinic for Diagnostic and Interventional Radiology zora Euler Andre joint author Solomon Justin joint author FitzGerald Paul F. joint author Samei Ehsan joint author Nelson Rendon C. joint author Academic Radiology 26(5):640-650 https://www.zora.uzh.ch/159304 text/html WWW-Backlink auf das Repository 1 Journal Article PeerReviewed zora ZORA 856 40 https://www.zora.uzh.ch/159304 text/html WWW-Backlink auf das Repository ZORA 700 1- Euler Andre joint author ZORA 700 1- Solomon Justin joint author ZORA 700 1- FitzGerald Paul F. joint author ZORA 700 1- Samei Ehsan joint author ZORA 700 1- Nelson Rendon C. joint author ZORA 773 0- Academic Radiology 26(5):640-650 BK010053 XK010053 XK010000 ZORA ZORA ZORA Journal Article closedAccess