Objective: The purpose of this study was to estimate perfusion metrics in healthy and cirrhotic liver with pharmacokinetic modeling of high-temporal resolution reconstruction of continuously acquired free-breathing gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced acquisition in patients undergoing clinically indicated liver magnetic resonance imaging.
Subjects and methods: In this Health Insurance Portability and Accountability Act-compliant prospective study, 9 cirrhotic and 10 noncirrhotic patients underwent clinical magnetic resonance imaging, which included continuously acquired radial stack-of-stars 3-dimensional gradient recalled echo sequence with golden-angle ordering scheme in free breathing during contrast injection. A total of 1904 radial spokes were acquired continuously in 318 to 340 seconds. High-temporal resolution data sets were formed by grouping 13 spokes per frame for temporal resolution of 2.2 to 2.4 seconds, which were reconstructed using the golden-angle radial sparse parallel technique that combines compressed sensing and parallel imaging. High-temporal resolution reconstructions were evaluated by a board-certified radiologist to generate gadolinium concentration-time curves in the aorta (arterial input function), portal vein (venous input function), and liver, which were fitted to dual-input dual-compartment model to estimate liver perfusion metrics that were compared between cirrhotic and noncirrhotic livers.
Results: The cirrhotic livers had significantly lower total plasma flow (70.1 ± 10.1 versus 103.1 ± 24.3 mL/min per 100 mL; P < 0.05), lower portal venous flow (33.4 ± 17.7 versus 89.9 ± 20.8 mL/min per 100 mL; P < 0.05), and higher arterial perfusion fraction (52.0% ± 23.4% versus 12.4% ± 7.1%; P < 0.05). The mean transit time was higher in the cirrhotic livers (24.4 ± 4.7 versus 15.7 ± 3.4 seconds; P < 0.05), and the hepatocellular uptake rate was lower (3.03 ± 2.1 versus 6.53 ± 2.4 100/min; P < 0.05).
Conclusions: Liver perfusion metrics can be estimated from free-breathing dynamic acquisition performed for every clinical examination without additional contrast injection or time. This is a novel paradigm for dynamic liver imaging.