Improved accuracy and precision with three-parameter simultaneous myocardial T and T mapping using multiparametric SASHA.

Purpose: To develop and validate a three-parameter model for improved precision multiparametric SAturation-recovery single-SHot Acquisition (mSASHA) cardiac T and T mapping with high accuracy in a single breath-hold.

Methods: The mSASHA acquisition consists of nine images of variable saturation recovery and T preparation in 11 heartbeats with T and T values calculated using a three-parameter model. It was validated in simulations and phantoms at 3 T with comparison to a four-parameter joint T -T technique.

Acellular bioscaffolds redirect cardiac fibroblasts and promote functional tissue repair in rodents and humans with myocardial injury.

Coronary heart disease is a leading cause of death. Tissue remodeling and fibrosis results in cardiac pump dysfunction and ischemic heart failure. Cardiac fibroblasts may rebuild damaged tissues when prompted by suitable environmental cues.

Hyperventilation-induced heart rate response as a potential marker for cardiovascular disease.

An increase of heart rate to physical or mental stress reflects the ability of the autonomous nervous system and the heart to respond adequately. Hyperventilation is a user-controlled breathing maneuver that has a significant impact on coronary function and hemodynamics. Thus, we aimed to investigate if the heart rate response to hyperventilation (HRR) can provide clinically useful information.

Epicardial infarct repair with bioinductive extracellular matrix promotes vasculogenesis and myocardial recovery.

Background: Infarcted myocardium can remodel after successful reperfusion, resulting in left ventricular dilation and heart failure. Epicardial infarct repair (EIR) using a bioinductive extracellular matrix (ECM) biomaterial is a novel surgical approach to promote endogenous myocardial repair and functional recovery after myocardial infarction. Using a pre-clinical porcine model of coronary ischemia-reperfusion, we assessed the effects of EIR on regional functional recovery, safety, and possible mechanisms of benefit.

Myocardial oxygenation is maintained during hypoxia when combined with apnea - a cardiovascular MR study.

Oxygenation-sensitive (OS) cardiovascular magnetic resonance (CMR) is used to noninvasively measure myocardial oxygenation changes during pharmacologic vasodilation. The use of breathing maneuvers with OS CMR for diagnostic purposes has been recently proposed based on the vasodilatory effect of Co2, which can be enhanced by the additive effect of mild hypoxia. This study seeks to investigate this synergistic concept on coronary arteriolar resistance with OS CMR.

Breathing manoeuvre-dependent changes in myocardial oxygenation in healthy humans.

Aims: CO₂ is an intrinsic vasodilator for cerebral and myocardial blood vessels. Myocardial vasodilation without a parallel increase of the oxygen demand leads to changes in myocardial oxygenation. Because apnoea and hyperventilation modify blood CO₂, we hypothesized that voluntary breathing manoeuvres induce changes in myocardial oxygenation that can be measured by oxygenation-sensitive cardiovascular magnetic resonance (CMR).

Saturation recovery single-shot acquisition (SASHA) for myocardial T(1) mapping.

Purpose: To validate a new saturation recovery single-shot acquisition (SASHA) pulse sequence for T1 mapping and to compare SASHA T1 values in heart failure patients and healthy controls.

Theory: The SASHA sequence consists of 10 electrocardiogram-triggered single-shot balanced steady-state free precession images in a breath-hold. The first image is acquired without magnetization preparation and the remaining nine images follow saturation pulses with variable saturation recovery times.

Assessment of acute myocarditis by cardiovascular MR: diagnostic performance of shortened protocols.

The recommended cardiovascular magnetic resonance (CMR) diagnostic criteria for active myocarditis ("Lake Louise Criteria") are based on edema-sensitive (T2-weighted) imaging and two different contrast-enhanced techniques, the early gadolinium enhancement ratio (EGEr) and late gadolinium enhancement (LGE). Because fast spin echo sequences used for determining the EGEr and edema-sensitive T2-weighted sequences have inconsistent image quality, these components are often skipped in institutional standard protocols. We aimed to compare the diagnostic performance of the Lake Louise Criteria with and without T2-weighted or early gadolinium-enhanced CMR imaging in a clinical setting.

Impact of intermittent apnea on myocardial tissue oxygenation--a study using oxygenation-sensitive cardiovascular magnetic resonance.

Background: Carbon dioxide (CO(2)) is a recognized vasodilator of myocardial blood vessels that leads to changes in myocardial oxygenation through the recruitment of the coronary flow reserve. Yet, it is unknown whether changes of carbon dioxide induced by breathing maneuvers can be used to modify coronary blood flow and thus myocardial oxygenation. Oxygenation-sensitive cardiovascular magnetic resonance (CMR) using the blood oxygen level-dependent (BOLD) effect allows for non-invasive monitoring of changes of myocardial tissue oxygenation.

Oxygenation-sensitive CMR for assessing vasodilator-induced changes of myocardial oxygenation.

Background: As myocardial oxygenation may serve as a marker for ischemia and microvascular dysfunction, it could be clinically useful to have a non-invasive measure of changes in myocardial oxygenation. However, the impact of induced blood flow changes on oxygenation is not well understood. We used oxygenation-sensitive CMR to assess the relations between myocardial oxygenation and coronary sinus blood oxygen saturation (SvO2) and coronary blood flow in a dog model in which hyperemia was induced by intracoronary administration of vasodilators.

Single-shot steady-state free precession can detect myocardial edema in patients: a feasibility study.

Purpose: To demonstrate the ability of single-shot, T(2)/T(1) weighted steady-state free precession (SSFP) to detect myocardial edema in patients with an acute myocardial infarction.

Materials And Methods: This study was performed in a series of patients (n = 10) referred for the assessment of acute myocardial infarcts (AMI). Localizers were used to obtain true short axis views of the left ventricle (LV).

Wave intensity analysis and the development of the reservoir-wave approach.

The parameters of wave intensity analysis are calculated from incremental changes in pressure and velocity. While it is clear that forward- and backward-traveling waves induce incremental changes in pressure, not all incremental changes in pressure are due to waves; changes in pressure may also be due to changes in the volume of a compliant structure. When the left ventricular ejects blood rapidly into the aorta, aortic pressure increases, in part, because of the increase in aortic volume: aortic inflow is momentarily greater than aortic outflow.

Wave intensity analysis of left ventricular filling: application of windkessel theory.

We extend our recently published windkessel-wave interpretation of vascular function to the wave intensity analysis (WIA) of left ventricular (LV) filling dynamics by separating the pressure changes due to the windkessel from those due to traveling waves. With the use of LV compliance, the change in pressure due solely to LV volume changes (windkessel pressure) can be isolated. Inasmuch as the pressure measured in the cardiovascular system is the sum of its windkessel and wave components (excess pressure), it can be substituted into WIA, yielding the isolated wave effects on LV filling.

Wave intensity analysis of left atrial mechanics and energetics in anesthetized dogs.

The left atrium (LA) acts as a booster pump during late diastole, generating the Doppler transmitral A wave and contributing incrementally to left ventricular (LV) filling. However, after volume loading and in certain disease states, LA contraction fills the LV less effectively, and retrograde flow (i.e.

Systemic venous circulation. Waves propagating on a windkessel: relation of arterial and venous windkessels to systemic vascular resistance.

Compared with arterial hemodynamics, there has been relatively little study of venous hemodynamics. We propose that the venous system behaves just like the arterial system: waves propagate on a time-varying reservoir, the windkessel, which functions as the reverse of the arterial windkessel. During later diastole, pressure increases exponentially to approach an asymptotic value as inflow continues in the absence of outflow.