Please use this identifier to cite or link to this item:
Type: Thesis
Title: Clinical analysis of liver function: development of a novel method for the detection of portosystemic shunts.
Author: Matthews, Todd James
Issue Date: 2014
School/Discipline: School of Medicine
Abstract: A portosystemic shunt (PSS) is defined as a congenital or acquired abnormal blood vessel that redirects blood around the liver without being filtered through hepatic parenchyma. PSS are thought to contribute to the distribution of isolated secondary metastases beyond the liver in 1.7 - 7.2% of all colorectal cancer patients without cirrhosis of the liver. No standardised clinical test for PSS yet exists and subsequently, the majority of PSS cases are detected incidentally through radiological means. To better identify PSS, a simple standardised clinical test for its detection is needed. The aim of this thesis was to develop a cost effective, non-invasive technique that can detect and measure PSS in a healthy liver model. Methods An artificial 8mm diameter PSS was created between the portal vein and the inferior vena in a pig model with a catheter inserted in the confluence of the hepatic veins for sample collection. A spectrum of compounds including indocyanine green (ICG), ¹³C-methacetin, sorbitol and lignocaine, were injected into the portal system. To analyse the pharmacokinetic nature of the shunt and liver, Evans blue dye and ¹⁴C-sucrose were also administered. ICG was measured via a LiMON® spectrometer attached to the pig’s snout, while levels of the other indicators were measured by serial blood and breath sample collection over a 40 minute period. The process was repeated with the PSS clamped as the control. Results Of the administered compounds, only ICG had the potential to clearly identify and quantify the shunt due to the rapid serial sampling via the LiMON®. Further simulations using ICG demonstrated that the shunted fraction can be calculated using the transit times, including mean residence time, lag time and pharmacokinetic modelling. Conclusion Although this study has not yet provided a concise method for PSS detection available for immediate clinical use, it does provide a large foundation for further exploration into a quantitative technique. A future PSS test would allow an added risk assessment for secondary cancer, and consequently individual cancer therapy may be better targeted for individual patient care.
Advisor: Maddern, Guy John
Dissertation Note: Thesis (Ph.D.) -- University of Adelaide, School of Medicine, 2014
Keywords: portosystemic shunt; liver; Park; Abernethy; abnormality; protocol; PTFE; LiMON; indocyanine green; 13CO2 breath test; swine
Provenance: This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at:
Appears in Collections:Research Theses

Files in This Item:
File Description SizeFormat 
01front.pdf544.83 kBAdobe PDFView/Open
02whole.pdf8.17 MBAdobe PDFView/Open
  Restricted Access
Library staff access only639.64 kBAdobe PDFView/Open
  Restricted Access
Library staff access only8.44 MBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.