Radiology: Perfusion CT may aid in liver disease staging

Perfusion CT scans of a 53-year-old man with minimal fibrosis show ROIs in the aorta, portal vein and liver. Image Source: Radiology

Perfusion CT may help discriminate between minimal and intermediate stages of fibrosis in patients with chronic liver disease, according to a study in the July issue of Radiology.

Maxime Ronot, MD, from the unit for training and research in medicine at Université Paris in Paris, and colleagues sought to prospectively assess the utility of perfusion CT for differentiating minimal from intermediate fibrosis in treatment-naïve patients with chronic hepatitis C virus infection.

For the study, 52 patients with treatment-naïve HCV infection underwent perfusion CT and percutaneous liver biopsy on the same day. The researchers measured portal vein, arterial and total liver perfusion, mean transit time and distribution volumes for the right and left liver lobes. Liver samples were scored for fibrosis, and fibrosis area was determined. They then tested the differences in quantitative perfusion parameters between patients with minimal fibrosis (score of F1) and those with intermediate fibrosis (score of F2 or F3).

In patients with intermediate fibrosis (F2 and F3) compared with those with minimal fibrosis (F1), the portal venous perfusion (87 mL vs. 138 mL) and total liver perfusion (107 mL vs. 169 mL) were significantly decreased, and the mean transit time was significantly increased (16 seconds vs. 13 seconds), according to Ronot and colleagues.

At multivariate analysis, the researchers wrote that only the mean transit time was an independent factor. Receiver operating characteristic curve analysis showed that a mean transit time threshold of 13.4 seconds allowed discrimination between minimal and intermediate fibrosis with a sensitivity of 71 percent and a specificity of 65 percent.

Based on the study, the investigators found that perfusion changes occur early during fibrosis in chronic hepatitis C virus infection and can be detected with perfusion CT.

Ronot and colleagues did not find any correlations between fibrosis stage and immunohistochemical markers or between perfusion parameters and immunohistochemical markers. The researchers said they “expected to at least find a relationship between the stage of fibrosis and vascular changes.”

“Perfusion CT may help to discriminate minimal from intermediate fibrosis,” the authors wrote. “Mean transit time appears to be the most promising perfusion parameter for differentiating between fibrosis stages, although the large amount of overlap in the measured parameters limits the clinical utility of this test at present.”