Blood Flow Quantitation by Positron Emission Tomography During Selective Antegrade Cerebral Perfusion.

Background: Perfusion strategies during aortic surgery usually comprise hypothermic circulatory arrest (HCA), often combined with selective antegrade cerebral perfusion (SACP) or retrograde cerebral perfusion. Cerebral blood flow (CBF) is a fundamental parameter for which the optimal level has not been clearly defined. We sought to determine the CBF at a pump flow level of 6 mL/kg/min, previously shown likely to provide adequate SACP at 20°C in pigs.

Enlargement of visual processing regions in social anxiety disorder is related to symptom severity.

Social anxiety disorder (SAD) is associated with altered brain function and structure, but most structural studies include small samples and findings are mixed. This study compared regional gray matter volume between 48 SAD patients and 29 healthy controls (HC) as well as the relationship between volume and symptom severity. Structural magnetic resonance images from SAD patients and HC were evaluated using standard voxel-based morphometry (VBM) processing in the SPM8 software package.

Discrimination between glioma grades II and III in suspected low-grade gliomas using dynamic contrast-enhanced and dynamic susceptibility contrast perfusion MR imaging: a histogram analysis approach.

Introduction: Perfusion magnetic resonance imaging (MRI) can be used in the pre-operative assessment of brain tumours. The aim of this prospective study was to identify the perfusion parameters from dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast (DSC) perfusion imaging that could best discriminate between grade II and III gliomas.

Methods: MRI (3 T) including morphological ((T2 fluid attenuated inversion recovery (FLAIR) and T1-weighted (T1W)+Gd)) and perfusion (DCE and DSC) sequences was performed in 39 patients with newly diagnosed suspected low-grade glioma after written informed consent in this review board-approved study.

Influence of blood/tissue differences in contrast agent relaxivity on tracer-based MR perfusion measurements.

Purpose: Perfusion assessment by monitoring the transport of a tracer bolus depends critically on conversion of signal intensity into tracer concentration. Two main assumptions are generally applied for this conversion; (1) contrast agent relaxivity is identical in blood and tissue, (2) change in signal intensity depends only on the primary relaxation effect. The purpose of the study was to assess the validity and influence of these assumptions.

Sex differences in volume and structural covariance of the anterior and posterior hippocampus.

Sex differences in episodic and spatial memory are frequently observed, suggesting that there may be sex-related structural differences in the hippocampus (HC). Earlier findings are inconsistent, possibly due to a known variability along the hippocampal longitudinal axis. Here, we assessed potential sex differences in hippocampal volume and structural covariance with the rest of the brain in young men and women (N=76), considering the anterior (aHC) and posterior (pHC) hippocampus separately.

Remembering our origin: gender differences in spatial memory are reflected in gender differences in hippocampal lateralization.

Gender differences in spatial memory favoring men are frequently reported, and the involvement of the hippocampus in these functions is well-established. However, little is known of whether this behavioral gender difference is mirrored in a gender difference in hippocampal function. Here we assessed hippocampal activity, using functional MRI, while 24 men and women moved through three-dimensional virtual mazes (navigation phase) of varying length, and at the end-point estimated the direction of the starting-point (pointing phase).

Prefrontal activity during response inhibition decreases over time in the postpartum period.

The postpartum period is characterized by complex hormonal changes, but human imaging studies in the postpartum period have thus far predominantly focused on the neural correlates of maternal behavior or postpartum depression, whereas longitudinal studies on neural correlates of cognitive function across the postpartum period in healthy women are lacking. The aim of this study was to longitudinally examine response inhibition, as a measure of executive function, during the postpartum period and its neural correlates in healthy postpartum women and non-postpartum controls. Thirteen healthy postpartum women underwent event-related functional magnetic resonance imaging while performing a Go/NoGo task.

The effect of premenstrual dysphoric disorder and menstrual cycle phase on brain activity during response inhibition.

Background: Premenstrual dysphoric disorder (PMDD) has generally not been associated with impulsive behavior. However, some studies suggest that women with PMDD have higher impulsivity scores than healthy controls and that brain activity during response inhibition may vary across the menstrual cycle. Therefore, our aim was to unravel potentially important cognitive aspects of PMDD by investigating brain activity during response inhibition in women with PMDD and healthy controls in relation to menstrual cycle phase.

Menstrual cycle effects on amygdala reactivity to emotional stimulation in premenstrual dysphoric disorder.

Premenstrual dysphoric disorder (PMDD) with luteal phase related anxiety and mood swings compromise quality of life in around 4% of reproductive women. While anxiety is related to amygdala function, prior studies on amygdala reactivity both in healthy controls and women with PMDD are inconsistent with respect to menstrual cycle effects. Here women with PMDD and healthy controls were exposed to emotional faces during the mid-follicular and late luteal phase, and mean blood-oxygen-level dependence (BOLD) signal changes in the amygdala were determined with functional magnetic resonance imaging (fMRI).

Acute sleep deprivation enhances the brain's response to hedonic food stimuli: an fMRI study.

Context: There is growing recognition that a large number of individuals living in Western society are chronically sleep deprived. Sleep deprivation is associated with an increase in food consumption and appetite. However, the brain regions that are most susceptible to sleep deprivation-induced changes when processing food stimuli are unknown.

Minimal safe arterial blood flow during selective antegrade cerebral perfusion at 20° centigrade.

Background: Selective antegrade cerebral perfusion (SACP) enables surgery on the aortic arch, where cerebral ischemia may cause neurologic sequels. This study aims to identify the minimum arterial flow level to maintain adequate cerebral perfusion during SACP in deep hypothermia in the pig.

Methods: Two groups of pigs were subjected to SACP at 20(°)C α-stat.