Improving the detection of hepatic metastases by the use of dynamic flow scintigraphy

Abstract

Leeds LS9 7TFIt has been shown that ultrasound and static isotope imaging are relatively insensitive for the detection of lesions <2cm diameter (Bryan et al., 1977). CAT scanning, although apparently more sensitive than these 2 methods still appears to have a limitation in detecting small lesions in the liver (Scherer et al., 1978). However, since it has been established that intrahepatic primary or secondary tumours are associated with an increased hepatic arterial blood flow (Breedis & Young, 1953) and time-activity curves generated. The time of the peak of the kidney curve was used to indicate the division between arterial and portal inflow phases of the liver curve. The quality of the bolus injection and its distribution was assessed by examination of the rise time of the kidney curve and studies were rejected if this was greater than 8 sec. After 3-point smoothing of the liver curve the average slopes of the 2 consecutive 8-second sections on either side of the arterial/portal division were calculated. The first slope was taken to represent arterial inflow and the second slope was taken to represent the portal inflow. The hepatic perfusion index (HPI) was expressed as a fraction of the arterial inflow to the total hepatic inflow. Static scans were independently assessed (P.J.R.) as being indicative or non-indicative of the presence of hepatic metastases. The results of the static and dynamic studies were correlated with findings at laparotomy for the presence or absence of hepatic metastases, which where possible were measured. The sites of these metastases were also noted. Figure 1 shows the distribution of HPI values in the positive laparotomy group, in the group of patients with no liver metastases and in the control group. It can be seen that 24/25 patients who were in the laparotomy positive group (96%) had HPI values above the normal range, the upper limit of normal in this series being 0.42. One patient with massive hepatic replacement by tumour had an HPI value of 0.15 but interestingly had a positive static scan. In those patients known to have hepatic involvement, the sensitivity of static scanning was 64%. Nine patients in this group had normal scans, but all had abnormal HPI values. The data for the negative laparotomy group are also shown but no definitive statement can be made until the follow-up

Preoperative Imaging Staging of Rectal Cancer

“…The two major fields of those studies include dynamic scintigraphic examinations and more recently color Doppler US. 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] .…”

Contrast‐Enhanced Doppler Perfusion Index

“…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.…”

“…9 Hepatic metastases receive an increased proportion of their blood supply from the hepatic artery than from the portal vein. Changes have been observed on dynamic scintigraphy 1,7,8,10 and Doppler sonography. 4,5,11 The Doppler perfusion index (DPI), defined as the ratio of the hepatic arterial volume flow to the sum of the hepatic artery and portal vein volume flow, has been used to detect the presence of small and occult liver metastases in patients with colorectal cancer.…”

Changes in hepatic haemodynamics in rats with overt liver tumour

“…These findings indicate that the presence of overt hepatic tumour results in gross derangements of hepatic blood flow. These changes must be taken into consideration when attempting to potentiate the delivery of cytotoxic drugs to hepatic tumour by manipulation of hepatic haemodynamics.The hepatic perfusion index (HPI), that is the ratio of hepatic arterial to total hepatic blood flow determined by dynamic scintigraphy is elevated in the presence of overt tumour in man (Leveson et al, 1983). Previous studies have suggested that the blood supply to overt liver tumour is derived principally from the hepatic artery (Taylor et al, 1979 Radionuclide studies Ten rats injected intraportally with either viable Walker cells or the same number of dead Walker cells and ten rats receiving saline were anaesthetised with intraperitoneal sodium pentobarbitone and the right common carotid artery exposed through a midline cervical incision.…”

“…The hepatic perfusion index (HPI), that is the ratio of hepatic arterial to total hepatic blood flow determined by dynamic scintigraphy is elevated in the presence of overt tumour in man (Leveson et al, 1983). Previous studies have suggested that the blood supply to overt liver tumour is derived principally from the hepatic artery (Taylor et al, 1979).…”