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|Title: ||An optimised patient-specific contrast formula based on cardiovascular dynamics improves vascular visualisation during computed tomography angiography|
|Authors: ||Saade, Charbel|
|Issue Date: ||28-Jan-2016|
|Publisher: ||University of Sydney|
Faculty of Health Sciences
The purpose of this thesis is to improve arterial opacification during computed tomography angiography (CTA) of the head and neck, thoracic and pulmonary vasculature by employing a novel patient-specific contrast regimen for each anatomic region.
CTA of the head and neck, thoracic and pulmonary vasculature was performed on 720 patients with suspected vascular pathology using a 64 channel computed tomography scanner and a dual barrel contrast injector. Patients were randomly assigned into two equal protocol groups: regimen A, the department’s conventional protocol, employed a fixed contrast volume, intravenously injected at a flow rate of 4.5 mL/s; regimen B involved the use of a patient-specific contrast formula based on measured patient cardiovascular dynamics. Each study calculated the mean cross-sectional opacification profile of the arteries and veins in their anatomical region and an arteriovenous contrast ratio (AVCR) and Mann-Whitney U non-parametric statistics were used to compare regimens. The diagnostic efficacy in head and neck CTA and thoracic CTA (non-gated and gated ECG technique) was assessed by receiver operating characteristic (ROC) analysis using Dorfman-Berbaum-Metz methodology, whilst the thoracic CTA additionally measured visual grading characteristic (VGC) . Pulmonary CTA comparisons employed jackknife alternative free-response receiver operating characteristic (JAFROC) methodology. Inter-observer variations were investigated using Kappa methods.
Mean arterial opacification in all anatomical locations were up to 58% higher (p <0.001)
following regimen B compared with A. In the venous system, attenuation was significantly lower
in regimen B than in regimen A with a maximum reduction of up to 93% (p <0.0001). There
were significant (p <0.0001) improvements in AVCR at each anatomical level by up to 93%.
ROC area under the curve (Az), JAFROC figure of merit (FOM) and VGC scores and the interobserver
variability were significantly higher in regimen B compared to A (p<0.002, p<0.0002
and p<0.02, p<0.004) respectively. The contrast volume in regimen B was significantly lower
compared to A by up to 67 % (p<0.001).
Novel individualised acquisition/contrast regimen significantly improves visualisation of
head and neck, thoracic and pulmonary arterial vasculature, whilst reducing contrast volume and
the potential risks of contrast induced nephrotoxicity during CTA.|
|Description: ||Medical Imaging and Radiation Sciences|
|Access Level: ||Access is restricted to staff and students of the University of Sydney . UniKey credentials are required. Non university access may be obtained by visiting the University of Sydney Library.|
|Rights and Permissions: ||The author retains copyright of this thesis. It may only be used for the purposes of research and study. It must not be used for any other purposes and may not be transmitted or shared with others without prior permission.|
|Type of Work: ||PhD Doctorate|
|Type of Publication: ||Doctor of Philosophy Ph.D.|
|Appears in Collections:||Sydney Digital Theses (University of Sydney Access only)|
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