Oliver Wieben

• PhD
• Professor (Associate) at University of Wisconsin–Madison

INTRODUCTION: Central arterial stiffness and cerebral blood flow (CBF) are inversely related. Poor cardiorespiratory fitness (CRF) and low physical activity (PA) are related to both higher arterial stiffness and lower CBF. The present study examined (i) whether CRF or PA moderate the relationship between arterial stiffness and CBF and (ii) whether...

Background Cerebral pulsatility (PI) is reportedly higher in individuals with AD and MCI compared to age matched controls and has been associated with greater beta‐amyloid (Aß) burden, but its relationship to other neurodegenerative biomarkers is unknown. Higher cardiorespiratory fitness (CRF) positively affects vascular function and is associated...

Background Increasing evidence supports the notion that vascular dysfunction contributes to the evolution of Alzheimer’s disease (AD). Cerebral pulsatility index (PI) is reportedly higher in AD and MCI compared to age matched controls and has been associated with greater beta‐amyloid (Aß) burden. Higher cardiorespiratory fitness (CRF) positively af...

Cerebral blood flow at rest declines with age. However, age-related changes in functional measures of cerebrovascular health including cerebrovascular reactivity and neurovascular coupling are not well understood. Additionally, the effect of apolipoprotein E (APOE) ε4, a strong genetic risk factor for Alzheimer’s disease, on cerebral blood flow and...

Large-scale clinical research studies often incorporate neuroimaging biomarkers to understand underlying pathologic changes that occur in aging and neurodegenerative disease and are associated with cognitive decline and clinical impairment. Of particular interest are neuroimaging methods designed to understand various aspects of cerebrovascular dis...

Cerebrovascular and neurological diseases exhibit sex-specific patterns in prevalence, severity, and regional specificity, some of which are associated with altered cerebral blood flow (CBF). Females often exhibit higher resting CBF, but understanding the impact of sex per se on CBF is hampered by study variability in age, comorbidities, medication...

Background Patients with syndromic heritable thoracic aortic diseases (sHTAD) who underwent prophylactic aortic root replacement are at high risk of distal aortic events, but the underlying mechanisms remain unclear. This prospective, longitudinal study evaluates the impact of valve-sparing aortic root replacement (VSARR) on aortic fluid dynamics a...

Purpose Tricuspid valve flow velocities are challenging to measure with cardiovascular MR, as the rapidly moving valvular plane prohibits direct flow evaluation, but they are vitally important to diastolic function evaluation. We developed an automated valve‐tracking 2D method for measuring flow through the dynamic tricuspid valve. Methods Nine he...

Background: Measuring cerebral blood flow (CBF) has been crucial in understanding brain function and health. Most studies use a resting CBF value for comparison when testing different experimental conditions on different days; however, it is unclear whether resting condition values can be repeated between days. This has important implications for i...

Background: Understanding the regulation of resting cerebral blood flow (CBF) is crucial in the realm of brain health as previous studies indicate reduced CBF is associated with an increased risk of several neurological and cerebrovascular conditions. Concurrently, cerebrovascular reactivity (CVR), which assesses the ability of blood vessels to res...

Background: Delivery of oxygen-rich gas (hyperoxia) is used to treat medical emergencies as well as to prevent adverse outcomes in certain occupations that are subjected to extreme environmental conditions. While useful for mitigating acute health risks, hyperoxia has been linked to health decrements including systemic vasoconstriction, increased o...

Background Recently, dynamic contrast‐enhanced (DCE) MRI with ferumoxytol as contrast agent has recently been introduced for the noninvasive assessment of placental structure and function throughout. However, it has not been demonstrated under pathological conditions. Purpose To measure cotyledon‐specific rhesus macaque maternal placental blood fl...

Partial thrombosis of the false lumen (FL) in patients with chronic aortic dissection (AD) of the descending aorta has been associated with poor outcomes. Meanwhile, the fluid dynamic and biomechanical characteristics associated with partial thrombosis remain to be elucidated. This retrospective, single-center study tested the association between F...

Purpose Traditional phase‐contrast MRI is affected by displacement artifacts caused by non‐synchronized spatial‐ and velocity‐encoding time points. The resulting inaccurate velocity maps can affect the accuracy of derived hemodynamic parameters. This study proposes and characterizes a 3D radial phase‐contrast UTE (PC‐UTE) sequence to reduce displac...

Animal data indicate that insulin triggers a robust nitric oxide synthase (NOS)-mediated dilation in cerebral arteries similar to the peripheral tissue vasodilation observed in healthy adults. Insulin's role in regulating cerebral blood flow (CBF) in humans remains unclear but may be important for understanding the links between insulin resistance,...

MRA is essential for neurovascular evaluation with applications in anatomic mapping, atherosclerotic disease, stroke, aneurysm, vascular malformations, and vascular dysfunction in neurodegenerative diseases. TOF MRA is the most used MRA technique but has some disadvantages. Many new and important advancements in flow imaging have emerged both witho...

4D Flow MRI is an advanced imaging technique for comprehensive non-invasive assessment of the cardiovascular system. The capture of the blood velocity vector field throughout the cardiac cycle enables measures of flow, pulse wave velocity, kinetic energy, wall shear stress, and more. Advances in hardware, MRI data acquisition and reconstruction met...

Hemodynamic assessment is an integral part of the diagnosis and management of cardiovascular disease. Four-dimensional cardiovascular magnetic resonance flow imaging (4D Flow CMR) allows comprehensive and accurate assessment of flow in a single acquisition. This consensus paper is an update from the 2015 '4D Flow CMR Consensus Statement'. We elabor...

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Spanish Ministry of Science, Innovation, and Universities Background Partial thrombosis of the false lumen (FL) in patients with chronic aortic dissection (AD) of the descending aorta has recently been associated with poor outcomes (1)...

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III (Spain), Sociedad Española de Cardiología Introduction Patients with Marfan or Loeys-Dietz syndrome present abnormal aortic flow patterns in the arch and the proximal descending aorta that may contribute t...

Introduction: Age-related changes in cerebral hemodynamics are controversial and discrepancies may be due to experimental techniques. As such, the purpose of this study was to compare cerebral hemodynamics measurements of the middle cerebral artery (MCA) between transcranial Doppler ultrasound (TCD) and four-dimensional flow MRI (4D flow MRI). Meth...

90 million Americans suffer metabolic syndrome (MetSyn), increasing risk of diabetes and poor brain outcomes including neuropathology linked to lower cerebral blood flow (CBF)-predominantly in anterior regions. We tested the hypothesis total and regional CBF is lower in MetSyn more so in the anterior brain and explored three potential mechanisms. 3...

Background: Adolescence is a key growth period that heavily influences future brain health. Approximately 1 in 5 adolescents are obese in the US, and up to half of them exhibit some form of insulin resistance (IR). Notably, insulin acts as a metabolic hormone, a neurotrophic growth factor, and a vasodilator. Reduced vasodilation may lead to reduced...

BACKGROUND: Greater cerebral blood flow pulsatility, measured as pulsatility index (PI), has recently been under investigation as a risk factor for cognitive impairment and neurodegenerative diseases. Furthermore, physical activity (PA), which has been associated with improved cognitive function and holds therapeutic effects for cardiovascular func...

Introduction: Sex differences in disease progression, prognosis, and location have been identified in stroke, aneurysms, and Alzheimer’s Disease (AD). These conditions are often associated with disturbed regional cerebral blood flow (CBF). Studies testing sex differences in CBF generally use transcranial doppler on the middle cerebral artery, leavi...

Background: The administration of oxygen-rich gas (hyperoxia), is a common treatment in clinical medicine and various military occupations. Hyperoxia reduces cerebral blood flow (CBF), however, there exists substantial variability in the magnitude of its effect (0-33%), as well as an uncertainty regarding the role that hypocapnia may play in this v...

Background: Approximately 20% of American adolescents are obese, and nearly half demonstrate some form of insulin resistance (IR). Insulin acts as a metabolic hormone, a neurotrophic growth factor, and a vasodilator. Notably, adults with neurologic disease often exhibit IR and reduced cerebral blood flow (CBF). Adolescent brains are actively growin...

Maternal inflammation can negatively impact the development of the fetus, leading to long term adverse health outcomes. We previously reported that injection of Tisseel (surgical glue) into the maternal-fetal interface led to necrosis and inflammation skewing the peripheral fetal immunome into a pro-inflammatory state. Here, we extend those observa...

Purpose This study addresses the challenges in obtaining abdominal 4D flow MRI of obese patients. We aimed to evaluate spectral saturation and inner volume excitation as methods to mitigating artifacts originating from adipose signals, with the goal of enhancing image quality and improving quantification. Methods Radial 4D flow MRI acquisitions wi...

Purpose The purpose of this work was to establish normal reference values for 4D flow MRI-derived flow, velocity, and vessel diameters, and to define characteristic flow patterns in the portal venous system of healthy adult subjects. Methods For this retrospective study, we screened all available 4D flow MRI exams of the upper abdomen in healthy a...

Background Characterizing cerebrovascular hemodynamics in older adults is important for identifying disease and understanding normal neurovascular aging. Four-dimensional (4D) flow MRI allows for a comprehensive assessment of cerebral hemodynamics in a single acquisition. Purpose To establish reference intracranial blood flow and pulsatility index...

Cerebrovascular disease (CVD) is associated with increased dementia risk and often co‐occurs with Alzheimer’s disease (AD). Non‐invasive quantitative 4D‐Flow MRI can be used to characterize cerebrovascular hemodynamics and study CVD/AD interactions during life, but has not been validated against postmortem pathological assessment. This study compar...

Background Patency of the false lumen in chronic aortic dissection (AD) is associated with aortic dilation and long-term aortic events. However, predictors of adverse outcomes in this population are limited. The aim of this study was to evaluate the relationship between aortic growth rate and false lumen flow dynamics and biomechanics in patients w...

Cerebrovascular disease (CVD) is associated with increased dementia risk and often co‐occurs with Alzheimer’s disease (AD). Non‐invasive quantitative 4D‐Flow MRI can be used to characterize cerebrovascular hemodynamics and study CVD/AD interactions during life, but has not been validated against postmortem pathological assessment. This study compar...

Objectives: In pulmonary hypertension associated with HFpEF (PH-HFpEF), identifying mechanisms of right ventricular: pulmonary arterial (RV:PA) uncoupling can be leveraged for sub-phenotyping and targeted therapies. In this study, we aim to distinguish mechanisms of RV:PA uncoupling in PH-HFpEF due to high RV afterload (afterload-sensitive; AS) and...

Introduction Abnormal aortic flow patterns in patients with a connective tissue disorder (CTD), such as Marfan or Loeys-Dietz syndrome, may contribute to aortic root dilation [1,2]. Valve sparing aortic root replacement, which is effective in reducing the risk of aortic dissection in case of severe dilation, may also normalize flow patterns beyond...

4D flow MRI is a quantitative MRI technique that allows the comprehensive assessment of time-resolved hemodynamics and vascular anatomy over a 3-dimensional imaging volume. It effectively combines several advantages of invasive and non-invasive imaging modalities like ultrasound, angiography, and computed tomography in a single MRI acquisition and...

Identification of placental dysfunction in early pregnancy with non-invasive imaging could be a valuable tool for assessing maternal and fetal risk. Dynamic contrast enhanced (DCE) magnetic resonance imaging (MRI) can be a powerful tool for interrogating placenta health. After inoculation with Zika virus or sham inoculation at gestation age (GA) 45...

Purpose To determine the variability of blood flow measurements using 4D flow MRI in the portal and mesenteric circulations and to characterize the effects of meal ingestion, time of day, and between-day (diurnal) variations on portal and mesenteric hemodynamics. Methods In this IRB-approved and HIPAA-compliant study, 7 healthy and 7 portal hypert...

Purpose: To measure native T1 values, a marker of diffuse fibrosis, by using cardiac MRI (CMR) in young adults born prematurely. Materials and methods: This secondary analysis of a prospective cohort study included young adults born moderately to extremely preterm and age-matched, term-born participants. CMR was performed with a 3.0-T imager tha...

Introduction: The purpose of this study was twofold: 1) to determine microvascular cerebral blood flow (CBF) during hypoxia and 2) to investigate the effect of Ketorolac, a cyclooxygenase (COX) inhibitor, on hypoxia stimulated CBF. Acute exposure to hypoxic conditions leads to an increase in CBF, which may be regionally specific. Studies investiga...

Introduction: Non-selective cyclooxygenase (COX) inhibition tests the role of COX on cerebrovascular control. Most studies using COX inhibitors (typically Indomethacin) demonstrate robust decreases in cerebral blood flow (CBF) (20-42%), but have focused primarily on middle cerebral artery (MCA) velocity, which does not quantify CBF or provide insi...

The central arteries dampen the pulsatile forces from myocardial contraction, limiting the pulsatility that reaches the cerebral vasculature, although there are limited data on this relationship with aging in humans. The purpose of this study was to determine the association between aortic stiffness and cerebral artery pulsatility index in young an...

Deep phenotyping of pulmonary hypertension (PH) with multimodal diagnostic exercise interventions can lead to early focused therapeutic interventions. In this study, we report methods to simultaneously assess pulmonary impedance, differential biventricular myocardial strain, and right ventricular: pulmonary arterial (RV:PA) uncoupling during exerci...

This review guides readers through the selection and setup of standardized MR angiography (MRA) protocols for the abdomen and pelvis for common clinical applications. Topics covered include renovascular MRA in potential kidney donors and in patients with hypertension; hepatic and mesenteric MRA in potential liver donors, patients with portal hypert...

Objectives: 4D flow MRI allows for a comprehensive assessment of intracardiac blood flow, useful for assessing cardiovascular diseases, but post-processing requires time-consuming ventricular segmentation throughout the cardiac cycle and is prone to subjective errors. Here, we evaluate the use of automatic left and right ventricular (LV and RV) se...

The central arteries dampen the pulsatile forces from myocardial contraction, limiting the pulsatility that reaches the cerebral vasculature, although there are limited data on this relationship with aging in humans. The purpose of this study was to determine the association between aortic stiffness and cerebral artery pulsatility index in young an...

Patients with pulmonary arterial hypertension (PAH) exhibit cardiac metabolic remodeling, which precedes right ventricular (RV) dysfunction and subsequent heart failure. In this proof-of-concept study of two PAH patients, we demonstrate RV glucose dependency that is unmasked by exercise using a novel in-bore PET/MRI metabolic stress test. This arti...

Evaluation of the hemodynamics in the portal venous system plays an essential role in many hepatic pathologies. Changes in portal flow and vessel morphology are often indicative of disease.Routinely used imaging modalities, such as CT, ultrasound, invasive angiography, and MRI, often focus on either hemodynamics or anatomical imaging. In contrast,...

Purpose Streamlines from 4D‐flow MRI have been used clinically for intracranial blood‐flow tracking. However, deterministic and stochastic errors degrade streamline quality. The purpose of this study is to integrate displacement corrections, probabilistic streamlines, and novel fluid constraints to improve selective blood‐flow tracking and emulate...

Introduction: In this study, we report novel methods to investigate impact of pulmonary arterial (PA) afterload with impedance and ventricular interdependency with myocardial strain on right ventricular (RV) reserve with exercise and RV:PA coupling. Hypothesis: In pre-capillary pulmonary hypertension (PH), RV is conditioned to a higher contractilit...

Introduction: Combined pre- and post-capillary pulmonary hypertension (Cpc-PH) is the most severe form of PH-LHF. While the impact of elevated left atrial and consequently elevated pulmonary venous (PV) pressure on Cpc-PH progression is well studied, little is known about how compromised PV flow secondary to LHF affects disease progression. To asse...

Objectives This study sought to assess the predictive value of wall shear stress (WSS) for colocalized ascending aorta (AAo) growth rate (GR) in patients with bicuspid aortic valve (BAV). Background BAV is associated with AAo dilation, but there is limited knowledge about possible predictors of aortic dilation in BAV patients with BAV. An increase...

The importance of nitric oxide (NO) in regulating cerebral blood flow (CBF) remains unresolved, due in part to methodological approaches, which lack a comprehensive assessment of both global and regional effects. Importantly, NO synthase (NOS) expression and activity appear greater in some anterior brain regions, suggesting region‐specific NOS infl...

Background Bicuspid aortic valve (BAV), a congenital heart defect, is associated with ascending aorta (AAo) dilation. Whether the high prevalence of dilation in BAV patients is related to alteration of aortic blood flow and thus in wall shear stress (WSS) [1,2], which have been associated with aortic wall degeneration [3], or intrinsic abnormalitie...

Background Preterm birth has been linked to an elevated risk of heart failure and cardiopulmonary disease later in life. With improved neonatal care and survival, most infants born preterm are now reaching adulthood. In this study, we used 4D flow cardiovascular magnetic resonance (CMR) coupled with an exercise challenge to assess the impact of pre...

Purpose: Despite the great potential and flexibility of 4D flow MRI for hemodynamic analysis, a major limitation is the need for time-consuming and user-dependent post-processing. We propose a fast four-step algorithm for rapid, robust, and repeatable flow measurements in the great vessels based on automatic placement of measurement planes and ves...

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Guala A. received funding from the Spanish Ministry of Science, Innovation and Universities. Background Bicuspid aortic valve (BAV), a congenital heart defect, is associated with ascending aorta dilation, possibly via alteration of aor...

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): La Marató de TV3, Instituto de Salud Carlos III through the project and Spanish Ministry of Science, Innovation and Universities. BACKGROUND Loeys-Dietz (LDS) and Marfan (MFS) syndromes are rare genetic connective tissue disorders asso...

Background Premature birth is associated with lower levels of cardiorespiratory fitness (CRF) but the underlying mechanisms responsible remain unclear. This study assessed whether differences in cardiac morphology or function mediate differences in CRF among adolescents and young adults born preterm. Methods Adolescents and young adults born moder...

Our purpose was to compare cerebral blood flow in the large intracranial vessels between healthy adults with (VAH+) and without (No VAH) vertebral artery hypoplasia. We also evaluated age-related differences in regional blood flow through the large cerebral arteries. Healthy young (n = 20; age = 25 ± 3 years) and older adults (n = 19; age = 61 ± 5...

Aims To assess aortic flow and stiffness in patients with Loeys–Dietz syndrome (LDS) by 4D flow and cine cardiovascular magnetic resonance (CMR) and compare the results with those of healthy volunteers (HV) and Marfan syndrome (MFS) patients. Methods and results Twenty-one LDS and 44 MFS patients with no previous aortic dissection or surgery and 3...

Purpose: To use four-dimensional (4D) flow MRI to measure intraventricular flow in young adults who were born prematurely to investigate mechanisms that may account for increased heart failure risk in this population. Materials and methods: In this secondary analysis of a prospective study, a total of 56 young adults participated in an observati...

Objective Bicuspid aortic valve (BAV), the most common congenital valve defect, is associated with increased risk of aortic dilation and related complications; however, current risk assessment is not effective. Most of BAV have three leaflets with a fusion between two of them of variable length. This study aimed to ascertain whether the extent of l...

Background: Extreme preterm birth conveys an elevated risk of heart failure by young adulthood. Smaller biventricular chamber size, diastolic dysfunction, and pulmonary hypertension may contribute to reduced ventricular-vascular coupling. However, how hemodynamic manipulations may affect right ventricular (RV) function and coupling remains unknown...

Individuals born very premature have an increased cardiometabolic and heart failure risk. While the structural differences of the preterm heart are now well-described, metabolic insights into the physiologic mechanisms underpinning this risk are needed. Here, we used dynamic fluorodeoxyglucose (FDG) positron emission tomography/magnetic resonance i...

Individuals born prematurely have smaller hearts, cardiac limitations to exercise, and increased overall cardiometabolic risk. The cardiac effects of acute hypoxia exposure as another physiologic stressor remain under explored. The purpose of this study was to determine the effects of hypoxia on ventricular function in adults born preterm. Adults b...

Background: Vessel-wall enhancement (VWE) on black-blood MRI (BB MRI) has been proposed as an imaging marker for a higher risk of rupture and associated with wall inflammation. Whether VWE is causally linked to inflammation or rather induced by flow phenomena has been a subject of debate. Purpose: To study the effects of slow flow, spatial resol...

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Spanish Ministry of Science, Innovation and Universities ; Instituto de Salud Carlos III Introduction The aorta is a 3D hollow, curvilinear elastic structure whose diseases have life-threatening consequences. Despite much effort has be...

Purpose Chronic mesenteric ischemia (CMI) is a rare disease with a particularly difficult diagnosis. In this study, 4D flow MRI is used to quantitatively evaluate mesenteric hemodynamics before and after a meal in patients suspected of having CMI and healthy individuals. Methods Nineteen patients suspected of CMI and twenty control subjects were a...

Purpose Radial sampling is one method to accelerate 4D flow MRI acquisition, making feasible dual‐velocity encoding (Venc) assessment of slow flow in the left ventricle (LV). Here, two radial trajectories are compared in vitro for this application: 3D radial (phase‐contrast vastly undersampled isotropic projection, PC‐VIPR) versus stack of stars (p...

Respiratory-gated four-dimensional phase-contrast vastly undersampled isotropic projection reconstruction (4D PC-VIPR) is magnetic resonance (MR) imaging technique that enables analysis of vascular morphology and hemodynamics in a single examination using cardiac phase resolved 3D phase-contrast magnetic resonance imaging. The present study aimed t...

Background Understanding cerebrovascular health in Alzheimer’s disease (AD) is vital, as the majority of individuals with dementia due to AD are also found to have vascular disease at autopsy. We examined the relationships between centrally and peripherally measured vascular health markers and amyloid accumulation across the AD clinical spectrum....

Background: Thoracic endovascular aortic repair (TEVAR) is becoming the preferred treatment option to repair the proximal descending aorta after rupture following blunt traumatic injury. However, hemodynamic and mechanic implications of this intervention are poorly understood. Exploiting the possibilities of 4D flow magnetic resonance imaging, hemo...

Introduction: Individuals born premature have smaller ventricular chambers volumes and a reduced cardiac reserve during exercise. Epidemiologic studies demonstrate increased risk of developing heart failure by young adulthood, though whether this is due primarily to systolic or diastolic dysfunction remains unresolved. Hypothesis: We hypothesize th...

Background Connective tissue disorders, such as Loeys-Dietz (LDS) and Marfan (MFS) syndromes, are rare genetic diseases associated with progressive aortic dilation. Aortic dissections have been observed at lower aortic root diameters in LDS than in MFS, and research on aortic flow dynamics and biomechanics in LDS is lacking. Purpose To evaluate ro...

Background: There is increasing evidence that vascular disease risk factors contribute to evolution of the dementia syndrome of Alzheimer's disease (AD). One important measure of cerebrovascular health is pulsatility index (PI) which is thought to represent distal vascular resistance, and has previously been reported to be elevated in AD clinical...

Purpose: To explore the feasibility of using four-dimensional (4D) flow MRI to quantify blood flow and kinetic energy (KE) in the heart during strenuous exercise. Materials and methods: For this prospective study, cardiac 4D flow MRI was performed in 11 healthy young adult participants (eight men, three women; mean age, 26 years ± 1 [standard de...

Importance Premature birth is associated with substantially higher lifetime risk for cardiovascular disease, including arrhythmia, ischemic disease, and heart failure, although the underlying mechanisms are poorly understood. Objective To characterize cardiac structure and function in adolescents and young adults born preterm using cardiac magneti...

Despite sexual dimorphism present in stroke and risk for Alzheimer’s disease, sex differences in cerebral blood flow regulation remain controversial. Discrepancies in the literature may be due to menstrual cycle control as well as the inherent difficulty of quantifying cerebral blood flow in humans. The purpose of this study was to evaluate the cer...

Microvascular cerebral perfusion (CP) is critical for adequate oxygenation of neuronal tissue in the brain. However, the mechanisms underlying proper CP regulation in humans have yet to be fully defined. Endothelin is a potent endogenous vasoconstrictor and appears to have a modest role in blood flow regulation in many peripheral vascular beds in h...

Approximately 80 million adults in the United States suffer from an insulin resistant state known as metabolic syndrome (MetSyn), associated with increased risk for strokes, cerebral infarcts and neurologic disease. Adults with MetSyn also exhibit increased peripheral arterial stiffness, but whether arterial stiffness occurs in the cerebral circula...

Hypoxia is known to increase cerebral blood flow and increase sympathetic nervous activity (SNA). Given the strong link between elevated vascular stiffness and cardiovascular diseases exhibiting elevated SNA, we tested whether a hypoxic stressor in healthy subjects would acutely change cerebral vascular stiffness. We hypothesized hypoxia would lead...

Endothelin‐1 (ET‐1) is a potent vasoconstrictor that regulates vascular tone by binding to the ET A receptors on vascular smooth muscle. In healthy humans, blockade of ET A receptors increases resting forearm blood flow. ET‐1 appears to contribute to poor outcomes in animal models of cerebral ischemia, but the role of ET‐1 signaling in control of b...

Purpose: 2D cine phase contrast (PC)-MRI is a standard velocimetry for the superior mesenteric artery (SMA); however, the optimal localization of the measurement plane has never been fully discussed previously. The purpose of this Institutional Review Board approved prospective and single arm study is to test whether flow velocimetry of the SMA wit...

We present multimodal imaging in the rare case of isolated unilateral pulmonary vein atresia in a 6 year-old boy, including analysis of hemodynamics by magnetic resonance acquisition technique of time-resolved three-dimensional phase contrast imaging (4D flow magnetic resonance imaging). This novel imaging method enables the quantification and espe...

Background : Acute myocardial infarction (AMI) alters left ventricular (LV) hemodynamics, resulting in decreased global LV ejection fraction and global LV kinetic energy. We hypothesize that anterior AMI effects localized alterations in LV flow and developed a regional approach to analyze these local changes with 4D flow MRI. Methods : 4D flow card...

The assessment of blood flow was one of the first clinically adopted quantitative measures in Magnetic Resonance Imaging (MRI). The underlying principle for this measurement is the phase-contrast mechanism, which encodes the motion of the blood into the image phase. 2D phase-contrast MRI has become a commonly used clinical tool, where blood velocit...