Assessment of the severity of liver disease and fibrotic change: The usefulness of hepatic CT perfusion imaging

Abstract

This study assessed the utility of CT perfusion for quantitative assessment of liver function and fibrosis. Tissue blood flow (TBF), tissue blood volume (TBV), mean transit time (MTT) and hepatic arterial fraction (HAF) were measured with CT perfusion using the deconvolution algorithm in 38 patients with chronic liver diseases and 10 patients without liver disease. Using Child-Pugh classification, 21 patients were classified as Child A, 10 as Child B, and 7 as Child C. In 20 patients, the degree of fibrosis was quantitated in surgicallyresected specimens and compared with the perfusion parameters. The mean TBF, TBV, MTT and HAF of patients without liver disease were 103.9±18 ml/min/100 g, 12.5±2.0 ml/ 100 g, 11.1±1.6 sec and 18.4±5.6%, respectively (±SD). The mean TBF of patients with Child A, B and C were 95.1±24, 86.7±29 and 75.5±6.5 ml/min/100 g, respectively. TBF tended to decrease with the severity of chronic liver disease. The mean HAF of patients with Child A, B and C were 18.6±8.3, 29.8±11.2 and 40.2±11.1%, respectively. HAF of patients without liver disease was significantly different from those of Child B and C (p<0.05, each). However, there were no significant differences in TBV and MTT between each groups. HAF correlated significantly with the degree of fibrosis (R 2 =0.588, p<0.05). Our results showed that parameters of CT perfusion correlated significantly with the severity of liver fibrosis and cirrhosis. Quantitative measurement of hepatic tissue blood flow by CT perfusion is useful for evaluation of the severity of disease and fibrotic change.

Perfusion CT imaging of the liver: review of clinical applications

“…In cirrhotic liver parenchyma, the arterial enhancement fraction determined by quantitative mapping is increased with increasing severity of cirrhosis (9,14). In a recent report, Kang et al (9) demonstrated that the use of quantitative mapping of the arterial enhancement fraction improved the diagnostic performance of multiphasic CT in detection of cirrhosis and prediction of disease severity.…”

The evaluation of haemodynamics in cirrhotic patients with spectral CT

“…This tube voltage and/or scanner-dependent phenomenon for CT numbers could be largely avoided with iodine concentration measurement, which makes accurate quantification possible. The value of AIF in patients with normal liver functionality in the control group was 0.25, which was in the range of normal HPI values reported [5,17]. It indicated that perhaps there was a good correlation between AIF and HPI.…”

“…The HPI, which is the ratio of hepatic arterial perfusion to that of total perfusion, is one of the most commonly obtained hepatic CT perfusion parameters [17]. The normal value of HPI varies according to different reports [5,18], which perhaps is a result of the different mathematic models, scanners or patient selections involved. However, in general, the normal value of HPI is between 1/4 and 1/3.…”

“…The HPI value in cirrhotic patients measured with CT perfusion scan usually increases in some degree because of the hepatic arterial buffer effect [5,8,20]. The haemodynamics of cirrhosis was relevant to its pathology.…”

“…Perfusion parameters, such as liver blood volume, blood flow (BF), mean transit time (MTT) and hepatic perfusion index (HPI), can be obtained by perfusion scans using the cine mode or dynamic shuttle mode and mathematic calculations [2][3][4]. Liver haemodynamic changes in cirrhotic patients with portal hypertension can be detected by calculating the liver perfusion parameters, including decreasing liver BF and increasing liver HPI, that are related to decreased liver function [1,5].…”