INTRODUCTION Global oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2 ) were quantified in a test-retest study. Cerebral blood flow (CBF) data, required for CMRO2 estimation, were obtained using dynamic susceptibility contrast MRI (DSC-MRI). OEF and CMRO2 were quantified using two separate data sets, that is, conventional high-resolution (HR) gradient echo (GRE) phas...

Neurological, CT and high-field (1.5T) magnetic resonance imaging (MRI) data were correlated in 6 patients previously clinically diagnosed as having suffered small vertebrobasilar infarct. MRI demonstrated infarcts in areas where CT was nearly always negative. MRI allowed very precise clinico-topographic correlations and appears to be the preferred imaging technique in vertebrobasilar infarcts.

Magnetic resonance imaging (MRI) is rapidly establishing itself as the primary and often the only imaging technique for many disorders of the CNS and it provides unique and invaluable additional information in many other situations. Emphasis is given here to the practical uses of MRI resources in clinical situations.

Functional magnetic resonance imaging (fMRI) and particularly resting state fMRI (rs-fMRI) is widely used to investigate resting state brain networks (RSNs) on the systems level. Echo planar imaging (EPI) is the state-of-the-art imaging technique for most fMRI studies. Therefore, improvements of EPI might lead to increased sensitivity for a large amount of studies performed every day. A number ...

One of the major objectives of functional magnetic resonance imaging studies is to infer regional neuronal activity in response to a stimulus or task. We consider a Bayesian approach which incorporates spatial and temporal dependence and allows for the task-related response to change dynamically over the scanning session. AMS 2000 subject classifications: Primary 62-02; secondary 62P10.

Measuring functional magnetic resonance imaging (fMRI) responses to parametric stimulus variations in imaging experiments can elucidate how sensory information is represented in the brain. However, a potential limitation of this approach is that fMRI responses reflect only a regional average of neuronal activity. For this reason stimulus-induced changes in fMRI signal may not always reflect how...

diffusion weighted imaging uses the signal loss associated with the random thermal motion of water molecules in the presence of magnetic field gradients to derive a number of parameters that reflect the translational mobility of the water molecules in tissues. with a suitable experimental set-up, it is possible to calculate all the elements of the local diffusion tensor (dt) and derived paramet...

introduction: the limited resolution of the imaging system causes partial volume effects (pves). these results in spreading of image counts to the neighboring pixels. this phenomenon is called spill-out effect. this study aimed at quantifying pves using imagej. methods:technetium-99m solution of concentration of 74 kbq/ml was filled into spheres a, b and c of diameters: 26 mm, 20 mm and 16 mm r...

Understanding the mechanism of coupling between neuronal events and hemodynamic responses is important in non-invasive functional imaging of the brain. The stimulus frequency dependence of hemodynamic responses has been studied using a rat somatosensory cortex model; most results for short stimulus durations reveal peak frequencies at which the hemodynamic response is maximized. However, such p...