Alastair J. Martin

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Recent studies have shown that the surface of the brain is deformed by up to 20 mm after the skull is opened during neurosurgery, which could lead to substantial error in commercial image-guided surgery systems. We quantitatively analyze the intraoperative brain deformation of 24 subjects to investigate whether simple rules can describe or predict the(More)
BACKGROUND AND PURPOSE Evolution of intracranial aneurysmal disease is known to be related to hemodynamic forces acting on the vessel wall. Low wall shear stress (WSS) has been reported to have a negative effect on endothelial cells normal physiology and may be an important contributor to local remodeling of the arterial wall and to aneurysm growth and(More)
Evolution of intracranial aneurysms is known to be related to hemodynamic forces such as wall shear stress (WSS) and maximum shear stress (MSS). Estimation of these parameters can be performed using numerical simulations with computational fluid dynamics (CFD), but can also be directly measured with magnetic resonance imaging (MRI) using a time-dependent 3D(More)
PURPOSE To determine the diagnostic performance of liver apparent diffusion coefficient (ADC) measured with conventional diffusion-weighted imaging (CDI) and diffusion tensor imaging (DTI) for the diagnosis of liver fibrosis and inflammation. MATERIALS AND METHODS Breathhold single-shot echo-planar imaging CDI and DTI with b-values of 0 and 500(More)
Current implementations of coronary artery magnetic resonance angiography (MRA) suffer from limited coverage of the coronary arterial system. Whole-heart coronary MRA was implemented based on a free-breathing steady-state free-precession (SSFP) technique with magnetization preparation. The technique was compared to a similar implementation of conventional,(More)
Fluid-attenuated inversion recovery (FLAIR) images obtained during the administration of supplemental oxygen demonstrate a hyperintense signal within the cerebrospinal fluid (CSF) that is likely caused by T1 changes induced by paramagnetic molecular oxygen. Previous studies demonstrated a linear relationship between the longitudinal relaxation rate (R1 =(More)
Clinical trials involving direct infusion of neurotrophic therapies for Parkinson's disease (PD) have suffered from poor coverage of the putamen. The planned use of a novel interventional-magnetic resonance imaging (iMRI) targeting system for achieving precise, real-time convection-enhanced delivery in a planned clinical trial of adeno-associated virus(More)
BACKGROUND The temporal progression in extent and severity of regional myofiber contractile dysfunction in normally perfused border zone (BZ) myocardium adjacent to a myocardial infarction (MI) has been shown to be an important pathophysiologic feature of the adverse remodeling process in large animal models. We sought, for the first time, to document the(More)
OBJECTIVE Our aim was to determine whether parallel imaging and diffusion tensor imaging affect the measurement of apparent diffusion coefficient (ADC) during diffusion-weighted MRI of the liver in healthy volunteers. SUBJECTS AND METHODS We performed breath-hold single-shot echo-planar diffusion-weighted MRI of the liver in 10 healthy volunteers using(More)
The patterns of length alterations in the hand bones in cases of pseudohypoparathyroidism (PHP), pseudopseudohypoparathyroidism (PPHP), and acrodysostosis were evaluated. The length of each of the hand bones was measured and compared to appropriate means for age and sex. The pattern profiles thus generated showed that those for PHP and PPHP are almost(More)