A Computer Modelling-Based Investigation of CTEPH

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dc.contributor.advisor Tawhai, M en
dc.contributor.advisor Clark, A en
dc.contributor.author Postles, Arthur en
dc.date.accessioned 2014-11-23T23:23:04Z en
dc.date.issued 2014 en
dc.identifier.citation 2014 en
dc.identifier.uri http://hdl.handle.net/2292/23566 en
dc.description.abstract Chronic Thromboembolic Pulmonary Hypertension (CTEPH) is a deadly disease of the pulmonary vasculature that develops from episodes of unresolved pulmonary embolism (PE). CTEPH is relatively rare, estimates of cases of CTEPH developing after PE range from 0.1% - 3.8%. Further to rarity, CTEPH exhibits a `honeymoon period' which is a symptomless period that may last months or even years. These two factors contribute to a poor understanding of the condition. Simply described, two features characterise CTEPH. The rst is the unresolved occlusion or occlusions in proximal arteries, creating a `two compartment vascular bed'; one compartment being the remaining open vasculature, and the other the occluded vasculature distal to proximal occlusions. The second feature is structural remodelling of blood vessels in the open vasculature, responding to chronically altered perfusion. Untreated, CTEPH causes progressive hypertension that eventually reaches levels where heart function fails. This research describes three computer modelling-based techniques aimed to provide new insight on CTEPH. In general, the application of computer models to this problem allow non-invasive techniques of investigation and provide data that is impossible to measure in experimental studies. The methods in this research use pulmonary circulation geometries that explicitly represent the entire branching structure of the pulmonary blood vessel tree from right heart, through the pulmonary capillaries, to left heart. Perfusion is simulated in these geometries, providing pressure and ow data throughout the entire system. The first technique proposed to investigate CTEPH alters the mechanical properties of the vessel geometry to simulate progressive vessel disease over a series of discrete steps representing stages of disease progression. Perfusion simulations at each step measure the predicted pressure and ow values in response. These simulations are intended to mimic the structural remodelling aspect of CTEPH. The proximal occlusion aspect of CTEPH is investigated by expanding upon the ideas of the remodelling simulations. First, methods are described for analysis of the volumetric CT scans for four subjects with CTEPH, allowing identifi cation of proximal occlusions by way of an intensity based flow map. The identi fied occlusions are included in perfusion simulations to characterise the unique manifestation of CTEPH in each subject. Simulations to this point are in the steady-state, however the fi nal investigation implements a pulsatile model in the geometry to investigate the nature of transient pressure and ow in health and disease. Initial perfusion simulations provided physiologically realistic results. Intensity-based ow mapping methods gave results consistent with CTEPH and proved useful in simulating subject-specifi c perfusion. The pulsatile model results showed trends that suggest links to the causes of vascular remodelling. Overall, this study has made some important steps toward modelling the lung in CTEPH patients. This will provide the basis for future studies in which models will be further refi ned and tested against clinical data. Ultimately, it is anticipated that model based analyses of function could be used to plan treatment and/or surgical strategies in CTEPH, reducing the cost of treatment and improving health. en
dc.publisher ResearchSpace@Auckland en
dc.relation.ispartof Masters Thesis - University of Auckland en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. en
dc.rights Restricted Item. Available to authenticated members of The University of Auckland. en
dc.rights.uri https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm en
dc.rights.uri http://creativecommons.org/licenses/by-nc-sa/3.0/nz/ en
dc.title A Computer Modelling-Based Investigation of CTEPH en
dc.type Thesis en
thesis.degree.grantor The University of Auckland en
thesis.degree.level Masters en
dc.rights.holder Copyright: The Author en
pubs.elements-id 462780 en
pubs.record-created-at-source-date 2014-11-24 en

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