The purpose of this study was to compare the effects of intermittent and continuous static exercise on muscle perfusion, perfusion heterogeneity, and oxygen extraction. Perfusion and oxygen uptake of quadriceps femoris muscle were measured in 10 healthy men by using positron emission tomography and [(15)O]H(2)O and [(15)O]O(2) first during intermittent static exercise [10% of maximal static for...

Physiology and pathophysiology of myocardial perfusion regulation and of myocardial perfusion reserve. Because of the high energy demands of myocardial contraction, the heart is critically dependent on oxidative metabolism, and insufficient myocardial oxygen delivery (i.e., ischemia) results almost instantaneously in contractile and electrical dysfunction. Because myocardial oxygen extraction i...

Background High-resolution quantitative analysis of myocardial blood flow (MBF) by cardiac magnetic resonance (CMR) perfusion has been recently proposed and validated in preclincal studies. It aims to combine the advantages of both visual assessment and quantitative analysis in a single test. However, incorrect registration between stress and rest images can hamper myocardial perfusion reserve ...

Background Adenosine perfusion imaging at 1.5 Tesla (T) has been shown to yield good diagnostic values in comparison to quantitative coronary angiography. Perfusion imaging at 3 T has the potential benefit of higher contrastand signalto-noise ratios. However, little is known about diagnostic performance of 3 T perfusion imaging in comparison to 1.5 T and in comparison to invasive measurement of...

Background—Impaired vasodilator function is an early manifestation of coronary artery disease and may precede angiographic stenosis. It is unknown whether noninvasive assessment of coronary vasodilator function in patients with suspected or known coronary artery disease carries incremental prognostic significance. Methods and Results—A total of 2783 consecutive patients referred for rest/stress...

OBJECTIVE We sought to determine the prognostic value of qualitative and quantitative analysis obtained by real-time myocardial perfusion echocardiography (RTMPE) in patients with known or suspected coronary artery disease (CAD). BACKGROUND Quantification of myocardial blood flow reserve (MBFR) in patients with CAD using RTMPE has been demonstrated to further improve accuracy over the analysi...

Background Cardiac magnetic resonance (CMR) perfusion imaging yields high diagnostic accuracy for the detection of coronary artery disease (CAD) [1]. However, standard 2D multislice CMR perfusion techniques only provide limited coverage and hence prohibit computation of myocardial ischemic burden. Recently, two single-center 3D CMR perfusion studies have proven highly diagnostic for the detecti...

BACKGROUND Impaired vasodilator function is an early manifestation of coronary artery disease and may precede angiographic stenosis. It is unknown whether noninvasive assessment of coronary vasodilator function in patients with suspected or known coronary artery disease carries incremental prognostic significance. METHODS AND RESULTS A total of 2783 consecutive patients referred for rest/stre...

To determine whether reductions in regional myocardial perfusion at reduced coronary arterial pressures reliably indicate maximal vasodilation of the distal vasculature, coronary autoregulation was studied in open-chest dogs at heart rates of approximately 60 beats/min, a level at which metabolic demand, time-averaged systolic compressive forces, and transmural vasodilator reserve approximate t...

1. Introduction pressure–flow relationship with a central portion running parallel to the pressure axis that is followed by a steep Essential hypertension is a main risk factor for left increase in flow at higher perfusion pressures (Fig. 2). If, ventricular hypertrophy (LVH), ischemic heart disease and however, coronary vessels are maximally dilated then such hypertensive cardiomyopathy [1]. I...