Sue Cheung

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Rapid T(1)-weighted 3D spoiled gradient-echo (GRE) data sets were acquired in the abdomen of 23 cancer patients during a total of 113 separate visits to allow dynamic contrast-enhanced MRI (DCE-MRI) analysis of tumor microvasculature. The arterial input function (AIF) was measured in each patient at each visit using an automated AIF extraction method(More)
Dynamic contrast-enhanced MRI (DCE-MRI) time series data are subject to unavoidable physiological motion during acquisition (e.g., due to breathing) and this motion causes significant errors when fitting tracer kinetic models to the data, particularly with voxel-by-voxel fitting approaches. Motion correction is problematic, as contrast enhancement(More)
Magnetic resonance imaging has shown promise for evaluating tissue oxygenation. In this study differences in the tissue longitudinal relaxation rate (R(1)) and effective transverse relaxation rate (R(*)(2)), induced by inhalation of pure oxygen and carbogen, were evaluated in 10 healthy subjects. Significant reductions in R(1) were demonstrated following(More)
BACKGROUND There is limited evidence that imaging biomarkers can predict subsequent response to therapy. Such prognostic and/or predictive biomarkers would facilitate development of personalised medicine. We hypothesised that pre-treatment measurement of the heterogeneity of tumour vascular enhancement could predict clinical outcome following combination(More)
RATIONALE AND OBJECTIVES The quantitative analysis of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) data is subject to model fitting errors caused by motion during the time-series data acquisition. However, the time-varying features that occur as a result of contrast enhancement can confound motion correction techniques based on(More)
Molecular oxygen has been previously shown to shorten longitudinal relaxation time (T1) in the spleen and renal cortex, but not in the liver or fat. In this study, the magnitude and temporal evolution of this effect were investigated. Medical air, oxygen, and carbogen (95% oxygen/5% CO2) were administered sequentially in 16 healthy volunteers. T1 maps were(More)
BACKGROUND AND PURPOSE ADC measurements have been shown to have an inverse relationship with tumor cell density. DCE-MR imaging modeling techniques can produce a measurement of the v(e), which would also be expected to have an inverse relationship with cell density. The objective of this study was to test the hypothesis that areas of increased cellularity,(More)
Dynamic contrast-enhanced MRI (DCE-MRI) is frequently used to provide response biomarkers in clinical trials of novel cancer therapeutics but assessment of their physiological accuracy is difficult. DCE-CT provides an independent probe of similar pharmacokinetic processes and may be modeled in the same way as DCE-MRI to provide purportedly equivalent(More)
BACKGROUND AND PURPOSE EnF is a newly described measure of proportional tumor enhancement derived from DCE-MR imaging. The aim of this study was to assess the relationship between EnF and the more established DCE-MR imaging parameters: K(trans), v(e), and v(p). MATERIALS AND METHODS Forty-two patients with 43 gliomas (16 grade II, 3 grade III, and 24(More)
Motion during time-series data acquisition causes model-fitting errors in quantitative dynamic contrast-enhanced (DCE) MRI studies. Motion correction techniques using conventional registration cost functions may produce biased results because they were not designed to deal with the time-varying information content due to contrast enhancement. We present a(More)