Myocardial perfusion imaging using adenosine-induced stress dual-energy computed tomography of the heart: comparison with cardiac magnetic resonance imaging and conventional coronary angiography.
ABSTRACT To evaluate the feasibility and diagnostic accuracy of adenosine-stress dual-energy computed tomography (DECT) for detecting haemodynamically significant stenosis causing reversible myocardial perfusion defect (PD) compared with stress perfusion magnetic resonance imaging (SP-MRI) and conventional coronary angiography (CCA).
Fifty patients with known coronary artery disease (CAD) detected by dual-source CT (DSCT) were investigated by contrast-enhanced, stress DECT with high- and low-energy x-ray spectra settings during adenosine infusion. A colour-coded iodine map was used for evaluation of myocardial PDs compared with rest DSCT perfusion images. Reversible myocardial PDs according to the stress DECT/rest DSCT were compared with SP-MRI on a segmental basis and CCA on a vascular territorial basis.
A total of 697 myocardial segments and 123 vascular territories of 41 patients were analysed. Three hundred one segments and 72 vascular territories in 38 patients showed reversible PDs on stress DECT. Stress DECT had 89% sensitivity, 78% specificity and 82% accuracy for detecting segments with reversible PDs seen on SP-MRI (n=28). Compared with CCA (n=41), stress DECT had 89% sensitivity, 76% specificity and 83% accuracy for the detection of vascular territories with reversible myocardial PDs that had haemodynamically relevant CAD.
Adenosine stress DECT can identify stress-induced myocardial PD in patients with CAD.
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ABSTRACT: Resting coronary flow and regional distribution are not affected by narrowing of up to 85 percent of arterial diameter and therefore provide little insight into the effects of stenoses on coronary hemodynamics. However, maximal coronary flow and coronary flow reserve are markedly reduced by constrictions that do not affect resting flow. Accordingly, coronary flow reserve and its relations to pressure-flow-resis-tance characteristics of 177 single (10 dogs) and 125 double coronary stenoses in series (7 dogs) were studied in open chest preparations. Coronary flow, aortic pressure and left circumflex coronary pressure distal to a single or to each of two separate adjustable coronary constrictors in series were simultaneously recorded while flow was varied from basal to maximum by intracoronary injections of contrast medium.The hyperemic response to contrast medium is a quantitative measure of coronary flow reserve which was closely related to, and predictive of, the following characteristics of single and double stenoses in series: (1) total pressure gradient and distal circumflex perfusion pressure at resting coronary flow; (2) total pressure gradient and distal circumflex pressure at hyperemic flow when effects of stenoses are greatest; and (3) coronary stenoses resistance. Thus, the hyperemic response after injection of contrast medium, or coronary flow reserve, is in itself a quantitative measure of the pressure-flow-resistance characteristics of coronary constrictions. In addition, resistances of coronary stenoses in series are shown to be additive; the flow effects of stenoses in series are not generally determined by the dominant or most severe lesion, contrary to common clinical precepts. These concepts are applicable to patients in assessing the effects of stenoses on coronary hemodynamics.The American Journal of Cardiology 08/1974; 34(1):48-55. · 3.21 Impact Factor
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ABSTRACT: The development of an ischemic event, whether silent or painful, represents the cumulative impact of a sequence of pathophysiologic events. Each ischemic episode is initiated by an imbalance between myocardial oxygen supply and demand that may ultimately be manifested as angina pectoris. This sequence of events can be termed the ischemic cascade. The significance of this concept resides in the fact that it redirects the focus from the end result--angina--to the more fundamental, underlying pathophysiologic factors that precede it. Specifically, these events include diminished left ventricular compliance, decreased myocardial contractility, increased left ventricular end-diastolic pressure, ST-segment changes and, occasionally, angina pectoris.The American Journal of Cardiology 04/1987; 59(7):23C-30C. · 3.21 Impact Factor