Estimating liver perfusion from free-breathing continuously acquired dynamic gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced acquisition with compressed sensing reconstruction

Abstract

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.

Figure 1

Schematic of two sets of GRASP reconstruction from the same continuous contrast-enhanced radial acquisition. Reconstruction from grouping 55 spokes per dynamic frame achieved temporal resolution of approximately 10 seconds which was used for morphologic assessment. GRASP reconstruction from grouping 13 spokes per frame achieved temporal resolution of 2.2-2.4 seconds which was employed for pharmacokinetic modeling.

Figure 2

Gadolinium concentration-time curve in aorta, main portal vein, and liver in a non-cirrhotic subject were fitted with dual input dual compartment model. Illustrative example of parametric maps of (A) Total plasma flow (F), (B) Arterial fraction (%ART), (C) Mean transit time (MTT), (D) and hepatocyte uptake rate (Ki) are shown for a single transaxial slice in one non-cirrhotic subject.

Figure 3

Box-plot of (A) Total plasma flow, (B) Arterial fraction (ART%), (C) Mean Transit Time (MTT) and (D) Hepatocellular uptake rate (Ki) in cirrhotic and non-cirrhotic subjects. Footnote: Center lines show the medians; box limits indicate the 25th and 75th percentiles; whiskers extend 1.5 times the interquartile range from the 25th and 75th percentiles, outliers are represented by dots.

Figure 4

Morphologic images in a non-cirrhotic patient demonstrating an FNH (arrow) on GRASP (A) arterial and (B) venous phase of enhancement. This lesion was similarly seen on prior breath-hold Cartesian (C) arterial and (D) venous phase acquisitions

Figure 5

Morphologic images in a patient with cholangiocarcinoma (arrow) on GRASP (A) arterial and (B) venous phase reconstruction. This lesion was seen on prior breath-hold Cartesian (C) arterial and (D) venous phase acquisitions. GRASP reconstruction with temporal resolution of 10 seconds demonstrates brisk arterial enhancement in this lesion with persistent enhancement on the delayed phase.