Toward nonparametric diffusion- characterization of crossing fibers in the human brain.

Purpose: To estimate for each distinct fiber population within voxels containing multiple brain tissue types.

Methods: A diffusion- correlation experiment was carried out in an in vivo human brain using tensor-valued diffusion encoding and multiple repetition times. The acquired data were inverted using a Monte Carlo algorithm that retrieves nonparametric distributions of diffusion tensors and longitudinal relaxation rates .

Prognostic impact of right ventricular mass change in patients with idiopathic pulmonary arterial hypertension.

Background: Compensatory remodelling i.e. increased right ventricular (RV) mass frequently occurs as an adaptive response to the chronic pressure overload to maintain contractile function.

A modified echocardiographic approach improves reliability of superior vena caval flow quantification.

Objective: To assess accuracy and repeatability of a modified echocardiographic approach to quantify superior vena cava (SVC) flow volume that uses a short-axis view to directly measure SVC area and a suprasternal view to measure flow velocity, both at the level of the right pulmonary artery.

Setting: Three tertiary-level neonatal intensive care units.

Design: This was a multicentre, prospective, observational study.

Nutritional Evaluation and Optimisation in Neonates: a randomized, double-blind controlled trial of amino acid regimen and intravenous lipid composition in preterm parenteral nutrition.

Background: Parenteral nutrition is central to the care of very immature infants. Current international recommendations favor higher amino acid intakes and fish oil-containing lipid emulsions.

Objective: The aim of this trial was to compare 1) the effects of high [immediate recommended daily intake (Imm-RDI)] and low [incremental introduction of amino acids (Inc-AAs)] parenteral amino acid delivery within 24 h of birth on body composition and 2) the effect of a multicomponent lipid emulsion containing 30% soybean oil, 30% medium-chain triglycerides, 25% olive oil, and 15% fish oil (SMOF) with that of soybean oil (SO)-based lipid emulsion on intrahepatocellular lipid (IHCL) content.

Pulmonary Artery Stiffness Is Independently Associated with Right Ventricular Mass and Function: A Cardiac MR Imaging Study.

Purpose To determine the relationship between pulmonary artery (PA) stiffness and both right ventricular (RV) mass and function with cardiac magnetic resonance (MR) imaging. Materials and Methods The study was approved by the local research ethics committee, and all participants gave written informed consent. Cardiac MR imaging was performed at 1.

Link Between Increased Satiety Gut Hormones and Reduced Food Reward After Gastric Bypass Surgery for Obesity.

Context: Roux-en-Y gastric bypass (RYGB) surgery is an effective long-term intervention for weight loss maintenance, reducing appetite, and also food reward, via unclear mechanisms.

Objective: To investigate the role of elevated satiety gut hormones after RYGB, we examined food hedonic-reward responses after their acute post-prandial suppression.

Design: These were randomized, placebo-controlled, double-blind, crossover experimental medicine studies.

Precursors of Hypertensive Heart Phenotype Develop in Healthy Adults: A High-Resolution 3D MRI Study.

Objectives: This study used high-resolution 3-dimensional cardiac magnetic resonance to define the anatomical and functional left ventricular (LV) properties associated with increasing systolic blood pressure (SBP) in a drug-naïve cohort.

Background: LV hypertrophy and remodeling occur in response to hemodynamic stress but little is known about how these phenotypic changes are initiated in the general population.

Methods: In this study, 1,258 volunteers (54% women, mean age 40.

Cardiovascular magnetic resonance of cardiac function and myocardial mass in preterm infants: a preliminary study of the impact of patent ductus arteriosus.

Background: Many pathologies seen in the preterm population are associated with abnormal blood supply, yet robust evaluation of preterm cardiac function is scarce and consequently normative ranges in this population are limited. The aim of this study was to quantify and validate left ventricular dimension and function in preterm infants using cardiovascular magnetic resonance (CMR). An initial investigation of the impact of the common congenital defect patent ductus arteriosus (PDA) was then carried out.

Preterm nutritional intake and MRI phenotype at term age: a prospective observational study.

Objective: To describe (1) the relationship between nutrition and the preterm-at-term infant phenotype, (2) phenotypic differences between preterm-at-term infants and healthy term born infants and (3) relationships between somatic and brain MRI outcomes.

Design: Prospective observational study.

Setting: UK tertiary neonatal unit.

Ghrelin mimics fasting to enhance human hedonic, orbitofrontal cortex, and hippocampal responses to food.

Background: Ghrelin, which is a stomach-derived hormone, increases with fasting and energy restriction and may influence eating behaviors through brain hedonic reward-cognitive systems. Therefore, changes in plasma ghrelin might mediate counter-regulatory responses to a negative energy balance through changes in food hedonics.

Objective: We investigated whether ghrelin administration (exogenous hyperghrelinemia) mimics effects of fasting (endogenous hyperghrelinemia) on the hedonic response and activation of brain-reward systems to food.

Adiposity and hepatic lipid in healthy full-term, breastfed, and formula-fed human infants: a prospective short-term longitudinal cohort study.

Background: The effect of mode of infant feeding on adiposity deposition is not fully understood.

Objective: The objective was to test the hypothesis that differences in total and regional adipose tissue content and intrahepatocellular lipid (IHCL) arise in early infancy between breast- and formula-fed infants and to describe longitudinal changes.

Design: This prospective longitudinal cohort study was performed in 2 hospitals in the United Kingdom.

Population-based studies of myocardial hypertrophy: high resolution cardiovascular magnetic resonance atlases improve statistical power.

Background: Cardiac phenotypes, such as left ventricular (LV) mass, demonstrate high heritability although most genes associated with these complex traits remain unidentified. Genome-wide association studies (GWAS) have relied on conventional 2D cardiovascular magnetic resonance (CMR) as the gold-standard for phenotyping. However this technique is insensitive to the regional variations in wall thickness which are often associated with left ventricular hypertrophy and require large cohorts to reach significance.

Obese patients after gastric bypass surgery have lower brain-hedonic responses to food than after gastric banding.

Objectives: Roux-en-Y gastric bypass (RYGB) has greater efficacy for weight loss in obese patients than gastric banding (BAND) surgery. We hypothesise that this may result from different effects on food hedonics via physiological changes secondary to distinct gut anatomy manipulations.

Design: We used functional MRI, eating behaviour and hormonal phenotyping to compare body mass index (BMI)-matched unoperated controls and patients after RYGB and BAND surgery for obesity.

Development of cortical microstructure in the preterm human brain.

Cortical maturation was studied in 65 infants between 27 and 46 wk postconception using structural and diffusion magnetic resonance imaging. Alterations in neural structure and complexity were inferred from changes in mean diffusivity and fractional anisotropy, analyzed by sampling regions of interest and also by a unique whole-cortex mapping approach. Mean diffusivity was higher in gyri than sulci and in frontal compared with occipital lobes, decreasing consistently throughout the study period.

Body fat is associated with reduced aortic stiffness until middle age.

Obesity is a major risk factor for cardiometabolic disease, but the effect of body composition on vascular aging and arterial stiffness remains uncertain. We investigated relationships among body composition, blood pressure, age, and aortic pulse wave velocity in healthy individuals. Pulse wave velocity in the thoracic aorta, an indicator of central arterial stiffness, was measured in 221 volunteers (range, 18-72 years; mean, 40.

Assessment of PDA shunt and systemic blood flow in newborns using cardiac MRI.

Patent ductus arteriosus (PDA) remains common in preterm newborns, but uncertainty over optimal management is perpetuated by clinicians' inability to quantify its true haemodynamic impact. Our aim was to develop a technique to quantify ductal shunt volume and the effect of PDA on systemic blood flow volume in neonates. Phase contrast MRI sequences were optimized to quantify left ventricular output (LVO) and blood flow in the distal superior vena cava (SVC) (below the azygos vein insertion), descending aorta (DAo) and azygos vein.

Salvage assessment with cardiac MRI following acute myocardial infarction underestimates potential for recovery of systolic strain.

Objectives: Our aim was to evaluate the relationship between the degree of salvage following acute ST elevation myocardial infarction (STEMI) and subsequent reversible contractile dysfunction using cardiac magnetic resonance (CMR) imaging.

Methods: Thirty-four patients underwent CMR examination 1-7 days after primary percutaneous coronary intervention (PPCI) for acute STEMI with follow-up at 1 year. The ischaemic area-at-risk (AAR) was assessed with T2-weighted imaging and myocardial necrosis with late gadolinium enhancement.

Neonatal cardiac MRI using prolonged balanced SSFP imaging at 3T with active frequency stabilization.

Unlabelled: Cardiac MRI in neonates holds promise as a tool that can provide detailed functional information in this vulnerable group. However, their small size, rapid heart rate, and inability to breath-hold, pose particular challenges that require prolonged high-contrast and high-SNR methods. Balanced-steady state free precession (SSFP) offers high SNR efficiency and excellent contrast, but is vulnerable to off-resonance effects that cause banding artifacts.

Remodeling after acute myocardial infarction: mapping ventricular dilatation using three dimensional CMR image registration.

Background: Progressive heart failure due to remodeling is a major cause of morbidity and mortality following myocardial infarction. Conventional clinical imaging measures global volume changes, and currently there is no means of assessing regional myocardial dilatation in relation to ischemic burden. Here we use 3D co-registration of Cardiovascular Magnetic Resonance (CMR) images to assess the long-term effects of ischemia-reperfusion injury on left ventricular structure after acute ST-elevation myocardial infarction (STEMI).

Disruption of intracardiac flow patterns in the newborn infant.

Introduction: Consistent patterns of rotational intracardiac flow have been demonstrated in the healthy adult human heart. Intracardiac rotational flow patterns are hypothesized to assist in the maintenance of kinetic energy of inflowing blood, augmenting cardiac function. Newborn cardiac function is known to be suboptimal secondary to decreased receptor number and sympathetic innervation, increased afterload, and increased reliance on atrial contraction to support ventricular filling.

The missing risk: MRI and MRS phenotyping of abdominal adiposity and ectopic fat.

Individual compartments of abdominal adiposity and lipid content within the liver and muscle are differentially associated with metabolic risk factors, obesity and insulin resistance. Subjects with greater intra-abdominal adipose tissue (IAAT) and hepatic fat than predicted by clinical indices of obesity may be at increased risk of metabolic diseases despite their "normal" size. There is a need for accurate quantification of these potentially hazardous depots and identification of novel subphenotypes that recognize individuals at potentially increased metabolic risk.

Functional cardiac MRI in preterm and term newborns.

Objective: To use cardiac MRI techniques to assess ventricular function and systemic perfusion in preterm and term newborns, to compare techniques to echocardiographic methods, and to obtain initial reference data.

Design: Observational magnetic resonance and echocardiographic imaging study.

Setting: Neonatal Unit, Queen Charlotte's and Chelsea Hospital, London, UK.

Assessment of severe reperfusion injury with T2* cardiac MRI in patients with acute myocardial infarction.

Background: In patients with acute myocardial infarction, restoration of coronary flow by primary coronary intervention (PCI) can lead to profound ischaemia-reperfusion injury with detrimental effects on myocardial salvage. Non-invasive assessment of interstitial myocardial haemorrhage by T2* cardiac MRI (T2*-CMR) provides a novel and specific biomarker of severe reperfusion injury which may be of prognostic value.

Objective: To characterise the determinants of acute ischaemia-reperfusion injury following ST elevation myocardial infarction (STEMI) using CMR.