Quantitative measurement of hepatic portal perfusion by multidetector row CT with compensation for respiratory misregistration

Abstract

Our purpose was to determine whether hepatic portal perfusion assessed by multidetector row CT using compensation for respiratory misregistration can predict the severity of chronic liver disease. We carried out dynamic CT in 43 patients (chronic hepatitis: n=9; cirrhosis: n=24; normal liver: n=10). In this series, 20 patients had liver tumours. The CT protocol was designed to avoid respiratory artefacts and included two interscan breathing periods during the study. To compensate for respiratory misregistration, image sets in the same z-axis position were acquired from four-slice data on each scan, and the portal perfusion calculations were made according to the maximum slope method. Portal perfusion was compared with and without compensation for respiratory misregistration, and the different types of hepatic disease. In the liver tumour patients in particular, portal perfusion was compared with the degree of hepatic fibrosis in the liver sections. Portal perfusion in the patients without compensation for respiratory misregistration (1.10 ml min(-1)ml(-1)) was higher than that of those with compensation (0.99 ml min(-1)ml(-1); p=0.036). Hepatic portal perfusion of patients with chronic hepatitis (0.97 ml min(-1)ml(-1)) and liver cirrhosis (0.88 ml min(-1)ml(-1)) was less than that of patients with normal liver (1.32 ml min(-1)ml(-1); p=0.03, 0.001). Moderate correlation was seen between portal perfusion and the percentage of fibrosis in patients with liver tumours (r=0.55). Hepatic portal perfusion obtained by multidetector row dynamic CT using compensation for respiratory misregistration has the potential to improve non-invasive assessment of the degree of chronic liver disease.

The evaluation of haemodynamics in cirrhotic patients with spectral CT

“…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.…”

“…Portal hypertension in patients with hepatic cirrhosis usually leads to changes in not only liver morphology but also liver perfusion and haemodynamics [1]. At present, a CT liver perfusion scan is one of the imaging means to obtain liver haemodynamics.…”

“…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].…”

“…Many patients cannot endure the long breath-hold time necessary for perfusion scans. As a result, motion artefacts often occur [6][7][8]. Another concern is the relatively high radiation dosage involved in cine scans [9][10][11].…”

Noninvasive assessment and monitoring of the pulmonary circulation

“…With the current multidetector row CT (MDCT) with o16 detectors, volumetric perfusion imaging of section of the lungs is, in theory, possible. However, CT perfusion research has been restricted to other areas outside the chest [19,20]. Figure 4 shows an example of a MDCT perfusion.…”