: The aim of the present study was to determine whether central benzodiazepine receptor binding potential (BRBP)/cerebral blood flow (CBF) or a combination of CBF and cerebrovascular reactivity (CVR) to acetazolamide on single-photon emission computed tomography (SPECT) more accurately detects misery perfusion, indicating elevation of absolute value of oxygen extraction ...

PURPOSE: The objective of this study was to evaluate the association between blood cadmium (Cd) and moderate-to-severe glomerular dysfunction in a Korean population using a representative sample. METHODS: A cross-sectional study was used to evaluate the association between blood Cd and glomerular dysfunction. Based on the Korean National Health and ...

In a fetal variation of circle of Willis (CoW) there is an embryological defect of the primary collateral circulation. Besides the fact that collateral flow cannot develop between anterior and posterior circulation, the tentorium namely prevents cerebellar vessels from connecting to the supra-tentorium territory. Therefore patients with a fetal variation ...

INTRODUCTION: We present data on the association of manganese (Mn) level with hypertension in a representative sample of the adult Korean population who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) 2008. METHODS: This study was based on the data obtained by KNHANES 2008, which was conducted ...

BACKGROUND: Insight into motivating factors and barriers for blood donation, especially for young people and underrepresented minorities, is important to donor recruitment and retention. We surveyed donors at a new blood collection facility based on a large, ethnically diverse university campus. STUDY DESIGN AND METHODS: Individuals who had donated or ...

BACKGROUND: Blood transfusion is a complex activity. Some of the components of this activity are implementation of standard procedures, evaluation of appropriateness of the blood use, methods for bedside identification of patients and the release of blood in emergencies, during out-of-routine hours and from hospitals lacking a Blood Centre. An ...

Microflow technology is established as a modern and fashionable tool in synthetic organic chemistry, bringing great improvement and potential, on account of a series of advantages over flask methods. The study presented here focuses on the application of flow chemistry process in performing an efficient multiple step syntheses of (±)-fluoxetine ...

Volunteer blood donors account for less than half of the blood supply in developing countries; and few countries have mobilized efforts to encourage voluntary blood donation (VBD). The objective of this study was to determine the knowledge and blood donation practices among adults in a state in Northern Nigeria. Descriptive ...

Microscope integrated indocyanine green video-angiography (ICG-VA) is a new technique for intraoperative assessment of blood flow that has been recently applied to the field of Neurosurgery. ICG-VA is known as a simple and practical method of blood flow assessment with acceptable reliability. Real time information obtained under magnification of operating ...

We present a technique to measure the longitudinal relaxation time constant of venous blood (T(1b) ) in vivo in a few seconds. The MRI sequence consists of a thick-slab adiabatic inversion, followed by a series of slice-selective excitations and single-shot echo planar imaging readouts. The time intervals between excitations were ...

As a consequence of neural stimulation the blood oxygenation-level dependent (BOLD) contrast in gradient-echo echo-planar imaging (GE-EPI) based functional MRI (fMRI) leads to an increased MR signal in activated brain regions. Following this, a BOLD signal undershoot below baseline is generally observed with GE-EPI. The origin of this undershoot has ...

The EP6-A protocol and Dr. Kroll's EP6-A extended methods are newly approved schemes for assessing linearity. Linearity surveys are used to evaluate the performances of clinical laboratories and improve the quality of tests. In accordance with the instruments used, the data of blood calcium were divided into four groups: Olympus ...

A major difference between arterial-spin-labeling MRI and gold-standard radiotracer blood flow methods is that the compartment localization of the labeled spins in the arterial-spin-labeling image is often ambiguous, which may affect the quantification of cerebral blood flow. In this study, we aim to probe whether the spins are located in ...

artifacts of respiratory motion are one of the well-known limitations of dynamic contrast-enhanced MRI (DCE-MRI) of the kidney. to propose and evaluate a retrospective triggering approach to minimize the effect of respiratory motion in DCE-MRI of the kidney. nine consecutive patients underwent renal perfusion measurements. Data were acquired with a ...

Arterial spin labeling-based cerebral blood flow imaging complements blood oxygenation level dependent (BOLD) imaging with a measure that is more quantitative and has better specificity to neuronal activation. Relative to gradient echo BOLD, spin echo BOLD has better spatial specificity because it is less biased to large draining veins. Although ...

The objective of this study was to develop a numerical solver to calculate the magneto-hydrodynamic (MHD) signal produced by a moving conductive liquid, i.e. blood flow in the great vessels of the heart, in a static magnetic field. We believe that this MHD signal is able to non-invasively characterize cardiac ...

Insight into the dynamics of blood-flow considerably improves the understanding of the complex cardiovascular system and its pathologies. Advances in MRI technology enable acquisition of 4D blood-flow data, providing quantitative blood-flow velocities over time. The currently typical slice-by-slice analysis requires a full mental reconstruction of the unsteady blood-flow field, which ...

To investigate pulmonary vein (PV) off-resonance and blood flow as causes of signal void artifacts in noncontrast steady-state-free-precession (SSFP) PV magnetic resonance angiography (MRA). PV blood off-resonance was measured on 11 healthy adult subjects and 10 atrial fibrillation (AF) patients. Noncontrast PV MRA was performed using a 3D slab-selective SSFP ...

X-ray videodensitometry allows in vivo flow measurements from gradients in contrast agent concentration. However, the injection of contrast agent alters the flow to be measured. Here, the temporal, spatial, and inter-patient variability of the response to injection are examined. To this purpose, an injection is prescribed in the internal carotid ...

We report the comprehensive evaluation of cardiac morphology, valve function, and three-dimensional (3D) blood flow in a pediatric patient with congenital heart disease. 3D visualization of cardiovascular flow paths and quantitative flow analysis based on flow-sensitive 4D magnetic resonance imaging (MRI) provided detailed insight into hemodynamic changes associated with valve ...

Expedient syntheses of Pseudomonas quinolone signal (PQS) and related structural analogues using microwave and flow methods are reported.

Objective: Previous studies have shown that the organ blood flows (OBFs) calculated using the T(1) weighted MRI technique were lower than the expected values. The aim of this study was a flow measurement comparison between the theoretical and experimental flows based on the technique before and after corrections (coil non-uniformity ...

Blood oxygen saturation (SO(2)) is a promising parameter for the assessment of brain tissue viability in numerous pathologies. Quantitative blood oxygenation level-dependent (qBOLD)-like approaches allow the estimation of SO(2) by modelling the contribution of deoxyhaemoglobin to the MR signal decay. These methods require a high signal-to-noise ratio to obtain accurate ...

Hemodynamically based functional neuroimaging techniques, such as BOLD fMRI and PET, provide indirect measures of neuronal activity. The quantitative relationship between neuronal activity and the measured signals is not yet precisely known, with uncertainties remaining about the relative contribution by their metabolic and hemodynamic components. Empirical observations have demonstrated the ...

We present a detailed study of hydrodynamics inside the flow-through dissolution apparatus when operated according to USP recommendations. The pulsatile flow inside the flow-through cell was measured quantitatively using magnetic resonance imaging (MRI) at a spatial resolution of 234 × 234 μm(2) and slice thickness of 1 mm. We report ...

Recent reports showed noxious forepaw stimulation in rats evoked an unexpected sustained decrease in cerebral blood volume (CBV) in the bilateral striatum, whereas increases in spike activity and Fos-immunoreactive cells were observed. This study aimed to further evaluate the hemodynamic and metabolic needs in this model and the sources of ...

BACKGROUND AND PURPOSE: In-stent restenosis (ISR) after angioplasty/stenting for intracranial stenosis has been reported in up to 25% to 30% of patients. Detection and monitoring of ISR relies primarily on serial catheter angiography, because noninvasive imaging methods are typically hampered by stent-related artifact. We examined the value of serial vessel ...

Phase contrast MRI is a powerful tool for the assessment of blood flow. However, especially in the highly complex and turbulent flow that accompanies many cardiovascular diseases, phase contrast MRI may suffer from artifacts. Simulation of phase contrast MRI of turbulent flow could increase our understanding of phase contrast MRI ...

A time-efficient method is described for in vivo venous blood T(1) measurement using multiphase inversion-recovery-prepared balanced steady-state free precession imaging. Computer simulations and validation experiments using a flow phantom were carried out to demonstrate the accuracy of the proposed method for measuring blood T(1) by taking advantage of the continuous ...

Breathing a mixture of 10% CO(2) with 90% O(2) (referred to here as carbogen-10) increases blood flow due to the vasodilatory effect of CO(2), and raises blood O(2) saturation due to the enriched oxygen level. These effects both tend to reduce the level of deoxygenated hemoglobin in brain tissues, thereby ...

Flow-spoiled fresh blood imaging, a noncontrast peripheral MR angiography technique, allows the depiction of the entire tree of peripheral arteries by utilizing the signal difference between systolic- and diastolic-triggered data. The image quality of the technique relies on selecting the right triggering delay times and flow-dependent read-out spoiler gradient pulses. ...

The purpose of this study was to investigate the feasibility of measuring blood flow to the retina using arterial spin labeling MRI, a quantitative, noninvasive tomographic technique. Blood flow imaging was performed in a single axial slice through both eyes of five healthy volunteers with no history of retinal diseases. ...

Reductions in blood oxygenation level dependent (BOLD)-functional magnetic resonance imaging (fMRI) signals below baseline levels have been observed under several conditions as negative activation in task-activation studies or anticorrelation in resting-state experiments. Converging evidence suggests that negative BOLD signals (NBSs) can generally be explained by local reductions in neural activity. ...

The case of an 8-year-old girl with atrial septal defect and associated anomalous pulmonary venous return is presented to illustrate the advantages of four dimensional flow (4D flow) over the current two dimensional flow (2D flow) in terms of time efficiency, easy planning, accurate and individual quantification of the blood ...

Cerebral blood flow (CBF) quantification is a valuable tool in stroke research. Mice are of special interest because of the potential of genetic engineering. Magnetic resonance imaging (MRI) provides repetitive, noninvasive CBF quantification. Many MRI techniques require the knowledge of the brain-blood partition coefficient (BBPC) for water. Adopting an MRI ...

We report a novel approach to biosensor-based observations of biomolecular interactions which enables real-time monitoring of biomolecular interactions in complex media. This approach is demonstrated by investigating the interaction between the human chorionic gonadotropin (hCG) and its antibody in blood plasma using a surface plasmon resonance biosensor and a dispersionless ...

The calibration of functional magnetic resonance imaging (fMRI) for the estimation of neuronal activation-induced changes in cerebral metabolic rate of oxygen (CMRO(2)) has been achieved through hypercapnic-induced iso-metabolic increases in cerebral blood flow (CBF). Hypercapnia (HC) has been traditionally implemented through alterations in the fixed inspired fractional concentrations of carbon ...

Relative cerebral blood volume (rCBV) measured using dynamic susceptibility contrast MRI suffers from interpatient and interstudy variability for the same tissue type. Traditionally, when a more quantitative assessment of rCBV is required, as for comparison across studies and patients, the rCBV values are normalized to the rCBV in a reference ...

To further validate the quantitative use of flow-sensitive four-dimensional velocity encoded cine magnetic resonance imaging (4D VEC MRI) for simultaneously acquired venous and arterial blood flow in healthy volunteers and for abnormal flow in patients with congenital heart disease. Stroke volumes (SV) obtained in arterial and venous thoracic vessels were ...

Pseudocontinuous arterial spin labeling (PCASL) has been demonstrated to provide the sensitivity of the continuous arterial spin labeling method while overcoming many of the limitations of that method. Because the specification of the phases in the radiofrequency pulse train in PCASL defines the tag and control conditions of the flowing ...

To evaluate the feasibility of flow-sensitive alternating inversion recovery (FAIR) for measuring blood flow in tumor models. In eight mice tumor models, FAIR and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was performed. The reliability for measuring blood flow on FAIR was evaluated using the coefficient of variation of blood flow ...

The formation of primitive (embryonic) blood in vertebrates is mediated by spatio-temporally restricted signaling between different tissue layers. In Xenopus, in which primitive blood originates in the ventral blood island, this involves the secretion of bone morphogenetic protein (BMP) ligands by the ectoderm that signal to the underlying mesoderm during ...

One of the characteristics of the blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) response to functional challenges of the brain is the poststimulation undershoot, which has been suggested to originate from a delayed recovery of either cerebral blood volume (CBV) or cerebral metabolic rate of oxygen to baseline. Using ...

A quantitative theory is developed for the relationship between stimulus and the resulting blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) signal, including both spatial and temporal dynamics for the first time. The brain tissue is modeled as a porous elastic medium, whose interconnected pores represent the vasculature. ...

Transport of bentazone, isoproturon, linuron, metamitron and metalaxyl were studied under three different flows in macrocosms. The aim was to verify the observations from Part I of the accompanying paper, with an increase in column volume and decrease in chemical and hydraulic load. Very limited breakthrough occurred in the macrocosms ...

We aimed to evaluate flow patterns in the superior vena cava (SVC) and azygos vein confluence with cine phase-contrast magnetic resonance imaging with consideration for the role played by the azygos arch valves. Two-dimensional cine phase-contrast magnetic resonance images of the SVC and azygos vein confluence were prospectively acquired in ...

Relative cerebral blood volume (CBV) was estimated using a mild hypoxic challenge in humans, combined with BOLD contrast gradient-echo imaging at 3 T. Subjects breathed 16% inspired oxygen, eliciting mild arterial desaturation. The fractional BOLD signal change induced by mild hypoxia is expected to be proportional to CBV under conditions ...

Inter-subject differences in local cerebral blood flow (CBF) and cerebral blood volume (CBV) contribute to differences in BOLD signal reactivity and, therefore, unmodelled variance in group level fMRI analyses. A simple way of elevating blood CO(2) concentrations to characterise subject differences in vascular reactivity is through breath-holds but two aspects ...

Three-dimensional (3D) time-of-flight (TOF) is now commonly used in routine magnetic resonance angiography (MRA) studies of the head and neck. However, there are limits to its diagnostic abilities in the clinical field and, in some instances, a more invasive supplementary examination may be required. We incidentally discovered a patient with ...

The hemodynamics within the aorta of five healthy humans were investigated to gain insight into the complex helical flow patterns that arise from the existence of asymmetries in the aortic region. The adopted approach is aimed at (1) overcoming the relative paucity of quantitative data regarding helical blood flow dynamics ...