Hepatocellular carcinoma: perfusion quantification with dynamic contrast-enhanced MRI

Abstract

Objective: The objective of our study was to report our initial experience with dynamic contrast-enhanced MRI (DCE-MRI) for perfusion quantification of hepatocellular carcinoma (HCC) and surrounding liver.

Subjects and methods: DCE-MRI of the liver was prospectively performed on 31 patients with HCC (male-female ratio, 26:5; mean age, 61 years; age range, 41-83 years). A dynamic coronal 3D FLASH sequence was performed at 1.5 T before and after injection of gadolinium-based contrast agent with an average temporal resolution of 3.8 seconds. Regions of interest were drawn on the abdominal aorta, portal vein, liver parenchyma, and HCC lesions by two observers in consensus. Time-activity curves were analyzed using a dual-input single-compartment model. The following perfusion parameters were obtained: arterial flow, portal venous flow, arterial fraction, distribution volume, and mean transit time (MTT).

Results: Thirty-three HCCs (mean size, 3.9 cm; range, 1.1-12.6 cm) were evaluated in 26 patients. When compared with liver parenchyma, HCC showed significantly higher arterial hepatic blood flow and arterial fraction (p < 0.0001) and significantly lower distribution volume and portal venous hepatic blood flow (p < 0.0001-0.023), with no difference in MTT. Untreated HCCs (n = 16) had a higher arterial fraction and lower portal venous hepatic blood flow value than chemoembolized HCCs (n = 17, p < 0.04).

Conclusion: DCE-MRI can be used to quantify perfusion metrics of HCC and liver parenchyma and to assess perfusion changes after HCC chemoembolization.

Fig. 1

64-year-old man with liver cirrhosis secondary to chronic hepatitis C and two untreated hepatocellular carcinomas (HCCs). A, Coronal dynamic contrast-enhanced MR images obtained with 3D FLASH sequence (TR/TE, 2.9/1.2; flip angle, 12°; voxel size, 2.6 × 2.1 × 4 mm; 1 average; parallel imaging factor, 3; temporal resolution, 6 seconds) covering entire liver before and after injection of 10 mL of gadopentetate dimeglumine. Two enhancing HCCs—one large lesion (arrows) and one small lesion (arrowheads)—are noted. Five selected time points from 40 measures are shown in chronologic order. B, Corresponding time-activity curve shows early enhancement of largest HCC. Arterial fraction (HCC vs liver parenchyma, 81.1% vs 40.8%, respectively) and arterial hepatic blood flow (188.7 vs 64.8 mL/100 g/min) were both increased in HCC, whereas portal venous hepatic blood flow (44.1 vs 94.2 mL/100 g/min) and mean transit time (13.3 vs 19.8 seconds) were decreased in HCC compared with liver parenchyma. PV = portal vein.

Fig. 2

Box plot distributions of estimated perfusion parameters of 33 hepatocellular carcinoma (HCC) lesions, including untreated HCCs, treated HCCs, and liver parenchyma, in 26 patients measured with dynamic contrast-enhanced MRI. Top and bottom lines of boxes show 25–75th percentiles of data values. Lines in boxes show median values, and target signs in boxes show mean values; asterisks show outliers. A, Arterial hepatic blood flow (F_a). B, Portal venous hepatic blood flow (F_p). C, Total hepatic blood flow (F_a + F_p). D, Arterial fraction. E, Distribution volume of gadolinium contrast material. F, Mean transit time (MTT) of gadolinium contrast material.

Fig. 3

Bar graph shows distribution of arterial fraction and portal venous fraction (portal venous fraction = 100% – arterial fraction) of untreated hepatocellular carcinomas (HCCs), treated HCCs, and liver parenchyma measured using dynamic contrast-enhanced MRI. Arterial fraction is decreased in treated HCCs compared with untreated HCCs.