William J. Ryder

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Microstructural white matter changes have been reported in the brains of patients across a range of psychiatric disorders. Evidence now demonstrates significant overlap in these regions in patients with affective and psychotic disorders, thus raising the possibility that these conditions share common neurobiological processes. If affective and psychotic(More)
Type 2 diabetes is characterised by decreased HDL levels, as well as the level of apolipoprotein A-I (apoA-I), the main apolipoprotein of HDLs. Pharmacological elevation of HDL and apoA-I levels is associated with improved glycaemic control in patients with type 2 diabetes. This is partly due to improved glucose uptake in skeletal muscle. This study used(More)
Attenuation correction of small animal PET data is very important when quantitative images are of interest. Attenuation correction coefficients are conventionally obtained via a transmission or a computed tomography scan, which require anaesthetisation of the animal. However, in the context of awake and/or freely moving animals, where animal motion is(More)
Elevated pancreatic β-cell cholesterol levels impair insulin secretion and reduce plasma insulin levels. This study establishes that low plasma insulin levels have a detrimental effect on two major insulin target tissues: adipose tissue and skeletal muscle. Mice with increased β-cell cholesterol levels were generated by conditional deletion of the(More)
UNLABELLED Accurate and reproducible SPECT quantification of myocardial molecular processes remains a challenge because of the complication of heterogeneous background and extracardiac activity adjacent to the heart, which causes errors in the estimation of myocardial focal tracer uptake. Our aim in this study was to introduce a heuristic method for the(More)
The temporal characterisation of endogenous neurotransmitter release during a cognitive task or drug intervention is an important capability for studying the role of neuro-transmitters in normal and aberrant brain function, including disease. Advanced kinetic models, such as the linear parametric neurotransmitter PET (lp-ntPET) have been developed to(More)
The Fast Molecular Imaging SimulaTor (FastMIST) is a hybrid analytical/Monte Carlo code which can simulate almost any arbitrary time-varying source distribution. Additionally, the position of each event can be spatially transformed according to a predefined temporal motion pattern allowing for the simulation of motion-corrupted data. The core algorithms are(More)
Awake and/or freely moving small animal single photon emission imaging allows the pseudo-continuous study of <sup>125</sup>I-labelled macromolecule kinetics, which could not otherwise be performed with systems involving restraint or anaesthesia. Estimating motion free projections in freely moving small animal planar imaging can be considered as a limited(More)
Attenuation correction in positron emission tomography brain imaging of freely moving animals is a very challenging problem since the torso of the animal is often within the field of view and introduces a non negligible attenuating factor that can degrade the quantitative accuracy of the reconstructed images. In the context of unrestrained small animal(More)
This paper describes the use of 18F-FDG and micro-PET/CT imaging to determine in vivo glucose metabolism kinetics in mice (and is transferable to rats). Impaired uptake and metabolism of glucose in multiple organ systems due to insulin resistance is a hallmark of type 2 diabetes. The ability of this technique to extract an image-derived input function from(More)