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Measurement of myocardial blood flow by 13NH3 relies heavily on the assessment of both the input function and the variable tissue extraction fraction. In six open-chest dogs, myocardial and arterial 13NH3 activity was measured both by in vitro sampling and by in vivo positron emission tomography (PET). Regional myocardial blood flow was forced to vary in(More)
According to the Stewart-Hamilton equation flow is inversely related to the area under the time-concentration curve produced by the transit of a detectable indicator. To verify the applicability of this principle for contrast echocardiography, we bolus injected a saccharide echo contrast agent (0.8 ml) into an in vitro circulatory model at variable flow(More)
OBJECTIVES The aim of this study was to explore the possibility of quantifying coronary blood flow by myocardial contrast echocardiography with air-filled serum albumin microspheres (Albunex). BACKGROUND Air-filled albumin microspheres have been proposed as an intravascular tracer for the study of myocardial perfusion by contrast echocardiography. (More)
The purpose of this study was to detect myocardial perfusion defects as a result of coronary occlusion and myocardial reperfusion after thrombolysis with intravenous (i.v.) administration of the echo contrast agent BR1 (Bracco Research, Switzerland), which consists of microbubbles (median diameter 2.5 microm) containing sulfur exafluoride in a(More)
The effects of acute subtotal embolisation of small coronary arteries on regional coronary flow and vasodilator reserve were investigated in seven open chest dogs. Unlabelled plastic microspheres (26(2) micron in diameter) were injected as boluses of 200,000-400,000 microspheres into the circumflex artery. Embolisation was repeated until reactive hyperaemia(More)
It has been shown in previous studies that myocardial contrast echocardiography provides quantitative information on coronary blood flow. However, the ability of contrast echo to assess the transmural (endo/epicardial) distribution of blood flow is still debated. To test this hypothesis, the left circumflex coronary arteries of six anaesthetized(More)
OBJECTIVES The aim of the study was to evaluate the relation between measurements derived from myocardial contrast echocardiography and coronary blood flow. BACKGROUND Contrast echocardiography has the potential for measuring blood flow. METHODS In six open chest anesthetized dogs, the left circumflex coronary artery was cannulated and perfused with(More)
From March 1977 to December 1982, 142 patients with varicocele of various sizes underwent preoperative antegrade or retrograde phlebography of the left spermatic vein. In 8 of them both procedures were carried out. A retrospective analysis of 68 preoperative antegrade venographies in supine (0 degree) and upright (30 degrees, 45 degrees and 90 degrees)(More)
UNLABELLED In 11 anaesthetised, Open chest dogs the time course and degree of the coronary vasodilating response to intracoronary adenosine infusion was assessed. Continuous adenosine infusion, at a rate of 2.5 to 13.5 mumol . min-1, produced rapid (15 to 30s) vasodilation of the same degree as that evoked by a 30 s period of ischaemia (reactive peak(More)
In order to assess the effects of dilazep on central hemodynamics and regional flows, 0.2 mg/kg of the drug were administered intravenously to 6 open-chest anesthetized dogs. Hemodynamic and flow measurements were performed under control conditions, and approximately 5, 10 and 25 min after treatment. Dilazep caused a marked and sustained reduction of(More)