scholarly journals Left and right ventricular hemodynamic forces in healthy volunteers and elite athletes assessed with 4D flow magnetic resonance imaging

2017 ◽  
Vol 312 (2) ◽  
pp. H314-H328 ◽  
Author(s):  
Per M. Arvidsson ◽  
Johannes Töger ◽  
Marcus Carlsson ◽  
Katarina Steding-Ehrenborg ◽  
Gianni Pedrizzetti ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Magnetic Resonance ◽  
Right Ventricular ◽  
Healthy Subjects ◽  
Elite Athletes ◽  
Left Ventricular ◽  
Resonance Imaging ◽  
4D Flow ◽  
Hemodynamic Forces

Intracardiac blood flow is driven by hemodynamic forces that are exchanged between the blood and myocardium. Previous studies have been limited to 2D measurements or investigated only left ventricular (LV) forces. Right ventricular (RV) forces and their mechanistic contribution to asymmetric redirection of flow in the RV have not been measured. We therefore aimed to quantify 3D hemodynamic forces in both ventricles in a cohort of healthy subjects, using magnetic resonance imaging 4D flow measurements. Twenty five controls, 14 elite endurance athletes, and 2 patients with LV dyssynchrony were included. 4D flow data were used as input for the Navier-Stokes equations to compute hemodynamic forces over the entire cardiac cycle. Hemodynamic forces were found in a qualitatively consistent pattern in all healthy subjects, with variations in amplitude. LV forces were mainly aligned along the apical-basal longitudinal axis, with an additional component aimed toward the aortic valve during systole. Conversely, RV forces were found in both longitudinal and short-axis planes, with a systolic force component driving a slingshot-like acceleration that explains the mechanism behind the redirection of blood flow toward the pulmonary valve. No differences were found between controls and athletes when indexing forces to ventricular volumes, indicating that cardiac force expenditures are tuned to accelerate blood similarly in small and large hearts. Patients’ forces differed from controls in both timing and amplitude. Normal cardiac pumping is associated with specific force patterns for both ventricles, and deviation from these forces may be a sensitive marker of ventricular dysfunction. Reference values are provided for future studies.NEW & NOTEWORTHY Biventricular hemodynamic forces were quantified for the first time in healthy controls and elite athletes (n = 39). Hemodynamic forces constitute a slingshot-like mechanism in the right ventricle, redirecting blood flow toward the pulmonary circulation. Force patterns were similar between healthy subjects and athletes, indicating potential utility as a cardiac function biomarker.

scholarly journals 4D flow magnetic resonance imaging to assess left atrial haemodynamics in healthy and hypertrophic subjects

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
X Morales Ferez ◽  
J Mill ◽  
G Delso ◽  
M Sitges ◽  
A Doltra ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Spectral Analysis ◽  
Magnetic Resonance ◽  
Healthy Subjects ◽  
Ventricular Dysfunction ◽  
Flow Patterns ◽  
Resonance Imaging ◽  
4D Flow ◽  
Blood Flow Patterns

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): - University, research centre and hospital foundation grants for the contracting of new research staff (FI 2020) - Spanish Ministry of Economy and Competitiveness Retos investigacion project Introduction The assessment of the left atrium (LA) haemodynamics is key to better understand the development of LA-related pathological processes. In this regard 4D flow magnetic resonance imaging (MRI) can provide complementary information to standard Doppler echocardiographic studies and identify complex blood flow patterns. Yet, until recently, the left atrium (LA) has been largely left aside in 4D flow MRI studies. Purpose We aimed at assessing the LA haemodynamics of healthy and hypertrophic cardiomyopathy (HCM) subjects with a qualitative visualization of flow patterns and deriving quantitative indices related to ventricular dysfunction from pulmonary veins (PV)  and mitral valve (MV) velocity profiles. Methods Segmentation was performed directly over 4D flow angiograms. A total of 20 cases were processed, 11 healthy and 9 HCM subjects. 4D velocity matrices were masked with the segmented mask to isolate LA haemodynamics. Velocity profiles were then obtained in the PV and MV and integrated over planes perpendicular to the lumen of the vessels to create velocity spectrograms. Fourier spectral analysis was applied to the velocity curves to highlight differences that might go unnoticed in the time domain. In addition, the Q-Criterion was computed for vortex identification, visually inspecting both cohorts across the whole cardiac cycle. Results Fourier spectral analysis of the velocity curves suggested that overall, healthy patients have higher dynamic range of the velocity curves. It can be observed in Figure 1, that the usual E/A MV velocity pattern is preserved in 10 of the 11 healthy subjects while 5 of the HCM patients present significant alterations of said curve. In fact, patients 4, 6, 7 and 8 seem to present a 3 peaked MV velocity curve. The vortex analysis identified 3 main types of vortices in healthy subjects: a ‘filling’ systolic vortex (10/11) arising near the most dominant PV (usually the left superior PV) as seen in Figure 2; a conduit phase vortex (7/11), similar in nature to the preceding systolic vortex; and an E-wave vortex (9/11) attached to the LA ostium. Four of the HCM patients (out of the five with altered MV velocity profile) also showed a systolic vortex, but with more complex blood flow patterns and emerging far from the PVs. One of such vortices is shown in Figure 2, composed of two distinct eddies near the MV. The E-wave vortex was also observed but was less predominant than in healthy subjects (3/9). Conclusions 4D Flow analysis of the LA is feasible and might hold promise in the understanding of the complex haemodynamics in ventricular dysfunction. Abstract Figure. Velocity Spectrograms and Vortices

scholarly journals Acute hypoxia increases the cerebral metabolic rate – a magnetic resonance imaging study

2015 ◽  
Vol 36 (6) ◽  
pp. 1046-1058 ◽  
Author(s):  
Mark B Vestergaard ◽  
Ulrich Lindberg ◽  
Niels Jacob Aachmann-Andersen ◽  
Kristian Lisbjerg ◽  
Søren Just Christensen ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Magnetic Resonance ◽  
Metabolic Rate ◽  
Oxygen Saturation ◽  
Healthy Subjects ◽  
Acute Hypoxia ◽  
Resonance Imaging ◽  
Cerebral Metabolic Rate

The aim of the present study was to examine changes in cerebral metabolism by magnetic resonance imaging of healthy subjects during inhalation of 10% O2 hypoxic air. Hypoxic exposure elevates cerebral perfusion, but its effect on energy metabolism has been less investigated. Magnetic resonance imaging techniques were used to measure global cerebral blood flow and the venous oxygen saturation in the sagittal sinus. Global cerebral metabolic rate of oxygen was quantified from cerebral blood flow and arteriovenous oxygen saturation difference. Concentrations of lactate, glutamate, N-acetylaspartate, creatine and phosphocreatine were measured in the visual cortex by magnetic resonance spectroscopy. Twenty-three young healthy males were scanned for 60 min during normoxia, followed by 40 min of breathing hypoxic air. Inhalation of hypoxic air resulted in an increase in cerebral blood flow of 15.5% ( p = 0.058), and an increase in cerebral metabolic rate of oxygen of 8.5% ( p = 0.035). Cerebral lactate concentration increased by 180.3% ([Formula: see text]), glutamate increased by 4.7% ([Formula: see text]) and creatine and phosphocreatine decreased by 15.2% ( p[Formula: see text]). The N-acetylaspartate concentration was unchanged ( p = 0.36). In conclusion, acute hypoxia in healthy subjects increased perfusion and metabolic rate, which could represent an increase in neuronal activity. We conclude that marked changes in brain homeostasis occur in the healthy human brain during exposure to acute hypoxia.

scholarly journals Right Ventricular Strain, Torsion, and Dyssynchrony in Healthy Subjects Using 3D Spiral Cine DENSE Magnetic Resonance Imaging

2017 ◽  
Vol 36 (5) ◽  
pp. 1076-1085 ◽  
Author(s):  
Jonathan D. Suever ◽  
Gregory J. Wehner ◽  
Linyuan Jing ◽  
David K. Powell ◽  
Sean M. Hamlet ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Right Ventricular ◽  
Healthy Subjects ◽  
Resonance Imaging ◽  
Right Ventricular Strain ◽  
Cine Dense

scholarly journals Characterization of Blood Flow Changes in Normal and Pathological Aortic Dilation from 4D Flow Magnetic Resonance Imaging

2019 ◽  
Author(s):  
Sophia Houriez-Gombaud-Saintonge ◽  
Ariel Pascaner ◽  
Gilles Soulat ◽  
Umit Gencer ◽  
Thomas Dietenbeck ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Magnetic Resonance ◽  
Resonance Imaging ◽  
Aortic Dilation ◽  
4D Flow ◽  
Flow Changes

scholarly journals Right and left ventricular function and flow quantification in pediatric patients with repaired tetralogy of Fallot using four-dimensional flow magnetic resonance imaging

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiaofen Yao ◽  
Liwei Hu ◽  
Yafeng Peng ◽  
Fei Feng ◽  
Rongzhen Ouyang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Pediatric Patients ◽  
Left Ventricular ◽  
Flow Quantification ◽  
Lv Function ◽  
Resonance Imaging ◽  
4D Flow ◽  
Ssfp Cine ◽  
Flow Measurements

Abstract Background To assess the accuracy and reproducibility of right ventricular (RV) and left ventricular (LV) function and flow measurements in children with repaired tetralogy of Fallot (rTOF) using four-dimensional (4D) flow, compared with conventional two-dimensional (2D) magnetic resonance imaging (MRI) sequences. Methods Thirty pediatric patients with rTOF were retrospectively enrolled to undergo 2D balanced steady-state free precession cine (2D b-SSFP cine), 2D phase contrast (PC), and 4D flow cardiac MRI. LV and RV volumes and flow in the ascending aorta (AAO) and main pulmonary artery (MPA) were quantified. Pearson’s or Spearman’s correlation tests, paired t-tests, the Wilcoxon signed-rank test, Bland–Altman analysis, and intraclass correlation coefficients (ICC) were performed. Results The 4D flow scan time was shorter compared with 2D sequences (P < 0.001). The biventricular volumes between 4D flow and 2D b-SSFP cine had no significant differences (P > 0.05), and showed strong correlations (r > 0.90, P < 0.001) and good consistency. The flow measurements of the AAO and MPA between 4D flow and 2D PC showed moderate to good correlations (r > 0.60, P < 0.001). There was good internal consistency in cardiac output. There was good intraobserver and interobserver biventricular function agreement (ICC > 0.85). Conclusions RV and LV function and flow quantification in pediatric patients with rTOF using 4D flow MRI can be measured accurately and reproducibly compared to those with conventional 2D sequences.

scholarly journals Modeling regional myocardial flows from residue functions of an intravascular indicator

1996 ◽  
Vol 271 (4) ◽  
pp. H1643-H1655 ◽  
Author(s):  
K. Kroll ◽  
N. Wilke ◽  
M. Jerosch-Herold ◽  
Y. Wang ◽  
Y. Zhang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Magnetic Resonance ◽  
Myocardial Blood Flow ◽  
Left Ventricular ◽  
Regional Myocardial Blood Flow ◽  
Resonance Imaging ◽  
Vascular Volume ◽  
Regional Flow ◽  
Regional Myocardial Blood

The purpose of the present study was to determine the accuracy and the sources of error in estimating regional myocardial blood flow and vascular volume from experimental residue functions obtained by external imaging of an intravascular indicator. For the analysis, a spatially distributed mathematical model was used that describes transport through a multiple-pathway vascular system. Reliability of the parameter estimates was tested by using sensitivity function analysis and by analyzing “pseudodata”: realistic model solutions to which random noise was added. Increased uncertainty in the estimates of flow in the pseudodata was observed when flow was near maximal physiological values, when dispersion of the vascular input was more than twice the dispersion of the microvascular system for an impulse input, and when the sampling frequency was < 2 samples/s. Estimates of regional blood volume were more reliable than estimates of flow. Failure to account for normal flow heterogeneity caused systematic underestimates of flow. To illustrate the method used for estimating regional flow, magnetic resonance imaging was used to obtain myocardial residue functions after left atrial injections of polylysine-Gd-diethylenetriaminepentaacetic acid, an intravascular contrast agent, in anesthetized chronically instrumental dogs. To test the increase in dispersion of the vascular input after central venous injections, magnetic resonance imaging data obtained in human subjects were compared with left ventricular blood pool curves obtained in dogs. It is concluded that if coronary flow is in the normal range, when the vascular input is a short bolus, and the heart is imaged at least once per cardiac cycle, then regional myocardial blood flow and vascular volume may be reliably estimated by analyzing residue functions of an intravascular indicator, providing a noninvasive approach with potential clinical application.

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