An experimental approach of the Doppler perfusion index of the liver in detecting occult hepatic metastases: histological findings related to the hemodynamic measurements in Wistar rats

Abstract

Image-directed colour Doppler sonography has been successfully introduced for the detection of hepatic haemodynamic changes in the presence of liver metastases. The aim of our study was to correlate these haemodynamic changes with the liver histology at the time of measurement. We experimentally induced liver metastases in 30 male Wistar rats by inoculating Walker 256 tumour subcutaneously. The animals were assigned into three groups of ten and were studied sonographically at 4, 7 and 15 days after tumour implantation. Another group of ten normal animals were used as controls. Portal vein and hepatic artery measurements included resistance index (PVRI, HARI) and flow volume (PVFV, HAFV). Doppler perfusion index (DPI) of the liver was calculated as the ratio of HAFV/PVFV + HAFV. Liver histology followed each Doppler measurement. Metastases were first encountered on day 4, as small groups of cells in the connective tissue of the porta hepatis and the portal triads without apparent vascular association. Distinct elevation of HAFV and DPI was recorded in comparison with the controls (p = 0.0004 and p = 0.0005, respectively). PVFV reduction was subtle. Up to day 15 there were no significant changes in the measurements. Our data suggest that HAFV and DPI can efficiently detect early liver metastases and this is in accordance with existing clinical reports. Haemodynamic changes seem to originate from the early non-vascular phase of the metastases.

Liver metastasis early detection using fMRI based statistical model

“…The association between hepatic metastases and altered liver blood flow has been demonstrated recently by dynamic scintigraphy [1], by Doppler sonography [2,3], by dynamic contrast enhanced CT [4] and more recently by dynamic contrast enhanced MRI [5]. Measurements using MRI can potentially overcome limitations posed by other imaging techniques, such as poor spatial resolution in radionuclide studies, lack of reproducibility in Doppler US and radiation exposure using CT.…”

Preoperative Imaging Staging of Rectal Cancer

“…The former is systematically described in the works of Leveson et al [78,79] ; the latter is extensively presented in the studies published by Leen et al [80] . Although the concept of hemodynamic changes due to the presence of hepatic metastases was confirmed experimentally, reproducibility of these techniques was not universally proven [81,82] . Hence the issue of occult hepatic metastases detection is still a major challenge that remains under investigation in the field of ongoing research.…”

Contrast‐Enhanced Doppler Perfusion Index

“…The mechanism is not clear, although changes have been shown to originate from the early nonvascular phase of the metastases 3 and may be mediated by circulating vasoactive agents as a response to neoplastic growth. 9 Hepatic metastases receive an increased proportion of their blood supply from the hepatic artery than from the portal vein.…”

“…t is known from experimental animal studies [1][2][3] and clinical patient studies [4][5][6][7][8][9] that the presence of even microscopic liver metastases is associated with changes in hepatic hemodynamics. The mechanism is not clear, although changes have been shown to originate from the early nonvascular phase of the metastases 3 and may be mediated by circulating vasoactive agents as a response to neoplastic growth.…”