Comparison of Gradient-Echo and Steady-State Free Precession for Coronary Artery Magnetic Resonance Angiography Using a Gadolinium-Based Intravascular Contrast Agent

Abstract

Intravascular contrast agents may offer longer imaging times and better vessel visualization over conventional extravascular agents for magnetic resonance coronary angiography. The purpose of this study was to evaluate the effect of intravascular contrast (B-22956/1) on coronary visualization. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were compared in inversion-recovery (IR)-prepared FLASH (fast low-angle shot) and IR-trueFISP (true fast imaging with steady-state precession) sequences before and after contrast. Numeric simulations were performed to compare blood signals in IR-trueFISP and IR-FLASH sequences. Coronary imaging was performed in 15 swine. Postcontrast CNR was improved 23% with breathhold IR-FLASH and 55% with breathhold IR-trueFISP as compared with precontrast trueFISP. With free-breathing, long TR IR-FLASH provided 131% and 55.8% higher SNR and 132% and 58.7% increased CNR compared with IR-FLASH with shorter TR and IR-trueFISP, respectively. Intravascular contrast agents improve CNR and vessel visualization in coronary magnetic resonance angiography with IR-FLASH and IR-trueFISP.