Splanchnic blood flow changes in the presence of hepatic tumour: evidence of a humoral mediator

Potential use of Doppler perfusion index in detection of occult liver metastases from colorectal cancer

Many clinical and preclinical studies demonstrated that measurements of liver hemodynamic [Doppler perfusion index (DPI)] may be used to accurately diagnose and predict liver metastases from primary colorectal cancer in a research setting. However, Doppler measurements have some serious limitations when applied to general population. Ultrasound is very operator-dependent, and requires skilled examiners. Also, many conditions may limit the use of Doppler ultrasound and ultrasound in general, such as the presence of air in digestive tract, cardiac arrhythmias, vascular anomalies, obesity and other conditions. Therefore, in spite of the results from clinical studies, its value may be limited in everyday practice. On the contrary, scientific research of the DPI in detection of liver metastases is of great importance, since current research speaks strongly for the presence of systemic vasoactive substance responsible for observed hemodynamic changes. Identification of such a systemic vasoactive substance may lead to the development of a simple and reproducible laboratory test that may reliably identify the presence of occult liver metastases and therefore increase the success of adjuvant chemotherapy through better selection of patients. Further research in this subject is therefore of great importance.

Relationship between CT volumetric measurements and Doppler perfusion indices in gastrointestinal liver metastasis

PURPOSE

This study investigated how the volume of hepatic metastatic lesions can affect liver haemodynamics and whether these perfusion parameters may help to differentiate benign and malignant liver lesions.

MATERIALS AND METHODS

The Doppler perfusion index (DPI the ratio of arterial to total liver blood flow) was measured in 46 patients aged 29-83 years, exhibiting up to four focal hyperechoic liver lesions at ultrasound examination. They comprised histopathologically proven liver metastasis of colorectal (19 cases) and gastric (10 cases) adenocarcinoma without local recurrence at the site of the previously resected primary tumour, along with 17 subjects with haemangioma. All patients underwent volumetric assessment using multislice computed tomography to calculate total volume of hepatic lesions.

RESULTS

The mean DPI of patients with colorectal (36 ± 2 %) and gastric (39 ± 6 %) metastasis was significantly higher than those with haemangioma (14 ± 2 %) (both p < 0.001), whereas metastatic groups did not exhibit any difference in terms of mean DPI. Statistically significant correlations were found between DPI values and calculated total volume of lesions in patients with colorectal and gastric metastasis (r = 0.55, p = 0.01 and r = 0.85, p = 0.002, respectively) while this correlation was not demonstrated in the haemangioma group. Simple linear regression analysis revealed that every 1 cm(3) increment in total volume of metastatic lesions increased DPI by 0.2 % [95 % confidence interval (CI) 0.1-0.3, p = 0.001].

CONCLUSION

Doppler perfusion index alterations are directly correlated with total volume of metastatic deposits, and DPI measurement can be a valuable method to distinguish haemangioma from hyperechoic colorectal and gastric metastatic lesions.

Preoperative hepatic CT perfusion as an early predictor for the recurrence of esophageal squamous cell carcinoma: initial clinical results

Reports suggest that hepatic blood flow may have an association with cancer progression. The aim of the present study was to evaluate whether the hepatic blood flow measured by CT perfusion (CTP) may identify patients at high-risk for postoperative recurrence of esophageal squamous cell carcinoma (ESCC). Prior to surgery, hepatic CTP images were obtained using a 320-row area detector CT. The data were analyzed by a commercially available software based on the dual input maximum slope method, and arterial blood flow (AF, ml/min/100 ml tissue), portal blood flow (PF, ml/min/100 ml tissue) and perfusion index [PI (%) = AF/AF + PF × 100] were measured. These parameters were compared with the pathological stage and outcome of the ESCC patients. Forty-five patients with ESCC were eligible for this study. The median follow-up period was 17 months, and recurrences were observed in 9 patients (20%). The preoperative PI values of the 9 patients with recurrence were significantly higher than those of the 36 patients without recurrence (23.9 vs. 15.9, P=0.0022). Patients were categorized into the following two groups; high PI (>20) and low PI (<20). The recurrence-free survival of the low PI group was significantly better than that of the high PI group (P<0.0001). A multivariate analysis showed that a high PI was an independent risk factor for recurrence (odds ratio, 19.1; P=0.0369). Therefore, the preoperative PI of the liver may be a useful imaging biomarker for predicting the recurrence of patients with esophageal cancer.

Doppler sonographic evaluation of hemodynamic changes in colorectal liver metastases relative to liver size

OBJECTIVE

The mechanisms of hemodynamic alterations in colorectal liver metastases are not clearly understood yet. Considering that an increase in liver size in patients with metastases could also result in an alteration in total liver flow, we aimed to analyze hemodynamic changes relative to the liver volume and to search for the possibility of any intrinsic factors affecting blood flow in patients with metastases.

METHODS

Twenty-eight patients with colorectal liver metastases and 20 control subjects with no liver disease were evaluated sonographically. All patients were examined prospectively by Doppler sonography and helical computed tomography. Hepatic hemodynamic parameters, including blood flow in the hepatic artery and portal vein, total blood flow to the liver, and Doppler perfusion index, were calculated, and values relative to liver volume were obtained. Hepatic perfusion changes in liver metastases were then compared with those in a control group.

RESULTS

The liver volume of the patients with liver metastases was greater than that of the control group (P=.003). Hepatic arterial blood flow rates were higher, whereas portal flow rates were lower, in patients with liver metastases compared with control subjects (P<.05). Total liver blood flow was not significantly different between the two groups. However, total blood flow relative to liver volume was significantly lower in the metastatic group (P<.001). Doppler perfusion index values in the patients with metastasis were significantly higher than in the control group (P=.000).

CONCLUSIONS

Our findings may support the hypothesis that a humoral mediator-induced portal venous flow reduction causes perfusion changes in liver metastases from colorectal disease. However, an additional intrinsic hepatic hemodynamic event should also be present. Doppler perfusion index measurements can provide additional information in the evaluation of patients with colorectal liver metastases.

Perfusion imaging of the liver: current challenges and future goals

Improved therapeutic options for hepatocellular carcinoma and metastatic disease place greater demands on diagnostic and surveillance tests for liver disease. Existing diagnostic imaging techniques provide limited evaluation of tissue characteristics beyond morphology; perfusion imaging of the liver has potential to improve this shortcoming. The ability to resolve hepatic arterial and portal venous components of blood flow on a global and regional basis constitutes the primary goal of liver perfusion imaging. Earlier detection of primary and metastatic hepatic malignancies and cirrhosis may be possible on the basis of relative increases in hepatic arterial blood flow associated with these diseases. To date, liver flow scintigraphy and flow quantification at Doppler ultrasonography have focused on characterization of global abnormalities. Computed tomography (CT) and magnetic resonance (MR) imaging can provide regional and global parameters, a critical goal for tumor surveillance. Several challenges remain: reduced radiation doses associated with CT perfusion imaging, improved spatial and temporal resolution at MR imaging, accurate quantification of tissue contrast material at MR imaging, and validation of parameters obtained from fitting enhancement curves to biokinetic models, applicable to all perfusion methods. Continued progress in this new field of liver imaging may have profound implications for large patient groups at risk for liver disease.

Nature of Doppler perfusion index changes in patients with colorectal cancer liver metastases

OBJECTIVE

Occult hepatic metastases from colorectal cancer result in an increase of the ratio of arterial hepatic blood flow to total hepatic blood flow, described as the Doppler perfusion index. Whether this alteration is due to an increase in arterial blood flow or a decrease in portal venous inflow has not yet been unequivocally determined. The purpose of this study was to analyze changes in hepatic perfusion in patients with liver metastases from colorectal cancer by standardization of hemodynamic parameters to body surface area.

METHODS

Hemodynamic parameters (crosssectional area, blood flow, and congestive index) were measured for the common hepatic artery and portal vein with duplex color Doppler sonography in 20 patients with liver metastases and 20 healthy control subjects and evaluated relative to body surface area.

RESULTS

No statistically significant differences in age, body surface area, cross-sectional area of the common hepatic artery, and congestion index of the common hepatic artery and portal vein were observed between control subjects and patients with liver metastases. Patients with liver metastases had significantly greater arterial hepatic blood flow and Doppler perfusion index and significantly smaller portal cross-sectional area portal blood flow as well as total liver blood flow (P <.001).

CONCLUSIONS

This study supports the theory that the primary mechanism of alteration in liver perfusion is the reduction of portal inflow with subsequently increased arterial hepatic blood flow.

Hepatic perfusion changes in mice livers with developing colorectal cancer metastases

PURPOSE

To evaluate whether intrahepatic flow alterations occur during formation of hepatic colorectal cancer metastases and to identify possible causes of these alterations.

MATERIALS AND METHODS

Intravital imaging of exteriorized livers was performed in 72 live mice. Three groups of mice were studied: a sham-operated control group (n = 24), a group with nonmetastasizing subcutaneous gliomas (n = 24), and a group with developing hepatic CX-1 colon cancer metastases (n = 24). Microvascular flow parameters, leukocyte-endothelial interactions, and wall shear stress were directly measured in hepatic sinusoids and postsinusoidal venules at 2-day intervals prior to and during the development of metastases. The Kruskal-Wallis test was used initially to test for overall equality of medians in each data group. Single posttest comparisons of independent samples were performed with the Mann-Whitney test, with an overall statistical significance of .05.

RESULTS

Prior to the development of visible colorectal cancer metastases, significant (P <.05) reductions occurred in sinusoidal and postsinusoidal flow and wall shear rates, coupled with increased leukocyte rolling and adherence. With tumor growth, flow was further compromised in 92% of tumors larger than 0.5 mm in diameter by extrinsic compression of sinusoids and portal venules and narrowing caused by adherent leukocytes.

CONCLUSION

Significant intrahepatic flow alterations occur in mouse livers prior to growth of visible metastases and provide a rational explanation for elevation in the Doppler perfusion index that occurs prior to tumor formation.

Functional ultrasound methods in oncological imaging

The real time nature of ultrasound and functional methods such as Doppler ultrasound mean that ultrasound can claim to have always been a functional imaging method, but recent developments in quantitation, dramatic improvement in Doppler performance and now microbubbles have created many exciting new applications. These include methods for assessing the neovascularity of tumours, for following the effects of therapy and for predicting the likelihood of development of metastatic disease at the staging of primary tumours.

Does the presence of distant and local malignancy alter parenchymal perfusion in apparently disease-free areas of the liver?

Our objective was to investigate if hepatic arterial (HAP) and portal venous perfusion (PVP) in apparently normal areas of liver, as measured by functional CT, are affected by the presence of extra- and intrahepatic malignancy Three patient groups were compared: A, controls with no malignancy (N = 10); B, extrahepatic malignancy without liver involvement (N = 12); and C, subjects with metastases elsewhere in the liver (N = 13). HAP, PVP, and a CT hepatic perfusion index (CT-HPI) calculated as HAP/(HAP + PVP) were calculated on a section free of metastatic disease, using a previously published method. Figures for PVP were (median and interquartile range) in group A were 1.06 (0.9-1.30), in B 1.03 (0.81-1.09), and in C 0.75 (0.54-1.02) ml/min/ml; for HAP group A values were 0.07 (0.052-0.078), in B 0.07 (0.053-0.147), and in C 0.12 (0.091-0.146) ml/min/ml and for CT-HPI Group A values were 4.9% (4.8-6.6%), in B 5.6% (3.8-13.6%), and in C 14.3% (10.4-15.4%). Significant differences in all indices were seen between groups A and C. A significant difference (P = 0.017) was seen between groups B and C in the CT-HPI values. In conclusion, patients with liver metastases show abnormal blood flow in apparently normal liver compared to controls. This difference was not seen in subjects with malignancy without liver metastases. Possible explanations would be either the unmasking of occult metastatic disease or vasoactive or mechanical effects due to liver malignancy.

The effect of resecting the primary tumour on the Doppler Perfusion Index in patients with colorectal cancer

AIM

In patients undergoing apparently curative resection for colorectal cancer, an elevated Doppler Perfusion Index (DPI; ratio of hepatic arterial to total liver blood flow) before surgery is associated with a high risk of recurrence. The role of the primary tumour in inducing and sustaining these blood flow changes is unknown. The aim of this study was to assess the impact of removing the primary tumour on the DPI.

MATERIALS AND METHODS

Using duplex/colour Doppler sonography, the DPI was measured both before and after surgery (median, 9 months) in 14 patients undergoing apparently curative resection for colorectal cancer.

RESULTS

In the five patients with a normal pre-operative DPI (< 0.30), there was no significant change following surgery. In the nine patients with an abnormal pre-operative DPI, there was a small but significant fall from 0.38 (SEM 0.02) to 0.33 (0.02) following surgery (P = 0.04). However, DPI values remained abnormally elevated in seven of these nine patients.

CONCLUSION

These results suggest that the primary tumour plays a relatively minor role in inducing an abnormally elevated DPI in patients undergoing apparently curative resection for colorectal cancer.Oppo, K. (2000). Clinical Radiology55, 791-793.

Raised levels of plasma big endothelin 1 in patients with colorectal cancer

BACKGROUND

The aim was to assess the role of plasma Big Endothelin (ET) 1 levels as a marker of disease presence and stage in colorectal adenocarcinoma.

METHODS

Big ET-1 was measured in the plasma of 37 patients with colorectal cancer. Preoperative systemic plasma levels of Big ET-1 in patients with cancer were compared with levels in 20 age- and sex-matched controls. Portal plasma samples were collected at operation in addition to peripheral venous samples. Immunohistochemical staining for Big ET-1 was performed on a selection of primary tumour specimens and liver metastases.

RESULTS

Median (range) preoperative systemic plasma levels of Big ET-1 were significantly higher in patients with cancer than in controls (1.0 (0.3-9.7) versus 0.2 (0.0-6.0) fmol/ml; P = 0.0001). Intraoperative portal plasma levels of Big ET-1 were significantly higher in patients with Dukes' 'D' disease than in patients with Dukes' A, B and C disease (2.1 (1.4-10.0) versus 1.2 (0.3-6.6) fmol/ml; P = 0. 01). Similarly, systemic plasma levels were significantly higher in patients with Dukes' 'D' disease than in those with localized disease (1.9 (1.2-9.7) versus 1.2 (0.2-8.3) fmol/ml; P = 0.01). The presence of microvascular invasion in the tumour specimens was associated with a significantly raised portal plasma level of Big ET-1 (1.6 (1.5-2.1) versus 1.1 (0.8-1.3) fmol/ml; P = 0.04). Immunohistochemistry localized Big ET-1 to the cancer epithelial cells.

CONCLUSION

The plasma level of Big ET-1 is significantly raised in patients with colorectal cancer. Patients with liver metastases have significantly higher levels than those with localized disease.

Alterations in hepatic perfusion resulting from splanchnic venous luminal compromise caused by pancreatic carcinoma

OBJECTIVE

We determined whether alterations in hepatic enhancement exist on dual phase helical CT of the liver in patients with splanchnic venous luminal compromise resulting from pancreatic adenocarcinoma.

SUBJECTS AND METHODS

We examined the extent of hepatic enhancement on dual phase helical CT in 22 patients with pancreatic adenocarcinoma. Eleven patients had splanchnic venous luminal narrowing (flattening along at least 120 degrees of the circumference) of the superior mesenteric vein with (n = 3) or without (n = 8) portal vein involvement caused by tumor. In the remaining patients, splanchnic vasculature appeared normal. An additional 16 patients without pancreatic or hepatic abnormality who underwent dual phase helical CT served as control subjects. We compared the extent of arterial phase and portal venous phase enhancement among the three groups.

RESULTS

The group of patients with splanchnic venous luminal compromise had significantly higher hepatic enhancement during the arterial phase (p < 0.01) and lower enhancement during the portal venous phase (p < 0.05) compared with the other two groups of patients. No significant difference in hepatic enhancement during either phase was noted between the control subjects and the patients with normal vasculature.

CONCLUSION

Because hepatic enhancement correlates with perfusion, splanchnic venous luminal compromise resulting from pancreatic adenocarcinoma likely causes decreased portal venous flow and compensatory increased hepatic arterial flow. This finding supports other evidence of a homeostatic mechanism that maintains hepatic perfusion.

Potential role of doppler perfusion index in selection of patients with colorectal cancer for adjuvant chemotherapy

BACKGROUND

As yet there is no established method of accurately identifying patients with colorectal cancer who, despite undergoing apparently curative resection, are at high risk of recurrence. We assessed whether the doppler perfusion index (DPI; ratio of hepatic arterial to total liver blood flow) could be used to select patients who should receive adjuvant chemotherapy.

METHODS

We studied 120 patients undergoing curative surgery for colorectal cancer. DPI was measured before surgery with colour duplex doppler ultrasonography. A DPI value of at least 0.3 was defined as abnormal. All patients were followed up until death or for at least 5 years.

RESULTS

At 5 years, patients with Dukes' stage A or B tumours (n=61) had recurrence-free survival of 57% and overall survival of 64%, compared with 39% and 42% for patients with Dukes' stage C tumours (n=59; p=0.016 and p=0.008, respectively). 47 patients had normal DPI values and 73 patients had abnormal values. Patients with normal DPI had recurrence-free survival of 89% and overall survival of 91%, compared with 22% and 29% for those with abnormal DPI values (both p<0.0001).

CONCLUSIONS

DPI can be used to identify patients with colorectal cancer at high risk of recurrence who are in need of adjuvant treatment. However, further studies with larger numbers of patients are needed to confirm these findings.

Prospective assessment of the hepatic perfusion index in patients with colorectal cancer

BACKGROUND

This prospective study was designed to test the hypothesis that abnormal liver blood flow is related to poor prognosis in patients with colorectal cancer.

METHODS

The hepatic perfusion index (HPI), measured by dynamic hepatic scintigraphy, was assessed in 202 patients with colorectal cancer. Assessment for overt hepatic metastasis included liver palpation at laparotomy and perioperative computed tomography (CT). Follow-up at a dedicated clinic included regular abdominal ultrasonography and CT.

RESULTS

The HPI was abnormal (greater than 0.37) in 92 (88 per cent) of 105 patients with overt liver metastases. Of 89 patients with no evidence of overt metastases or residual tumour after primary resection, 52 had an abnormal and 37 a normal HPI. At a median follow-up of 39 (range 13-76) months, 25 of 38 patients with recurrence had an abnormal HPI. Some 31 of 45 patients who died had an abnormal HPI. The HPI predicted overall recurrence (P=0.04, log rank test). Multivariate analysis showed the HPI was independent of Dukes stage for predicting disease-free survival (P=0.04, relative risk 1.94 (95 per cent confidence interval (c.i.) 1.03-3.67)) but this just failed to attain significance for overall survival (P=0.055, relative hazard 1.88 (95 per cent c.i. 1.00-3.58)).

CONCLUSION

The HPI predicts a poor outcome in patients with colorectal cancer and may be useful in patient selection for adjuvant chemotherapy.

Endothelin-1 and tumour development

There has been a growing conviction amongst oncologists that cancer is a disease characterized by changes in specific molecules. These changes include alteration in the structure, regulation or quantity of growth factors and their receptors, signal transducers and the proteins encoded by dominant or suppressor/recessive oncogenes. The role of endothelin (vasoactive peptide) in tumour cell signal transduction and mitogenesis and induction of endothelial cell growth and angiogenesis in tumour growth is discussed in this article.