Evaluation of Roentgen Cinedensitometry for Flow Measurement in Models and in the Intact Circulation

Rutishauser, W.; Simon, H; Stucky, J. P.; Schad, N.; Noseda, G; Wellauer, J

doi:10.1161/01.cir.36.6.951

Cited by 79 publications

(15 citation statements)

References 19 publications

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“…Instead, we found a decrease of Dma, with decreasing flow, which can be explained by the original principles of indicator dilution theory. The volume of indicator, that is, the contrast agent, will pass through the vascular compartment as a dispersed bolus, the rate of dispersion increasing with the length of time after injection.4 Because at low flow the moment of passage through a fixed ROI will be later than at high flow, the TDC at these low flows will be broader and have a lower peak.4 Justification for replacement of vascular volume by Dma,, in Equation 1 has been defended by postulating that for every pixel in an ROI, all blood in the corresponding vascular space will be totally replaced by contrast agent shortly after contrast injection.8'10 Although 6-8 ml of contrast agent is generally injected, however, a considerable part of this will leak away in the aorta, whereas in the Therefore, it should be emphasized that no information about resting flow can be obtained and that coronary flow reserve cannot be calculated. Our approach, however, does offer the ability to compare maximal myocardial blood flow before and after an appropriate intervention such as angioplasty or bypass surgery.…”

Section: Discussionmentioning

confidence: 99%

Mean transit time for the assessment of myocardial perfusion by videodensitometry.

et al. 1990

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The intrinsic limitations of coronary arteriography to predict the physiological effects of coronary obstructions are well known. Therefore, more direct assessments of the functional significance of coronary stenoses are becoming increasingly important. Study of contrast passage by electrocardiogram-triggered digital radiography has been proposed as a way of assessing changes in myocardial perfusion. The main problems in this approach are the limited time for motionless image acquisition, the potential alteration of vascular volume between different states, and the changing flow pattern induced by contrast agents. This has led to empiric substitution of mean transit time (Tmn) by other time parameters and to representation of vascular volume by maximal contrast intensity (D..). To avoid these problems, intact dogs were studied during almost motionless image acquisition of 20-25 consecutive paced heart beats obtained with synchronous radiographic pulses. In (weight, 26-36 kg) were anesthetized with sodium pentobarbital 25 mg/kg i.v., a left thoracotomy was performed, and epicardial pacing electrodes were sutured on the left atrium. The proximal part of the left circumflex artery (LCx) was gently dissected free, over a distance of 1.0-1.5 cm proximal of the origin of the first large obtuse marginal branch. A ring-mounted 20-MHz pulsed Doppler probe (Crystal Biotech Inc., Holliston, Massachusetts) was placed around the artery and a circular balloon occluder (R.E. Jones, Silver Springs, Maryland) was placed just distal to the Doppler probe. The pericardium and chest were closed, and the instrumentation leads were placed in a subcutaneous pocket until the time of study.At day 11 after instrumentation, each dog was anesthetized by nicomorphine 10 mg/hr i.v. and ethrane. The subcutaneous pocket was opened, and the wires of the Doppler probe were connected to the appropriate recording equipment (545C-4 Directional Pulsed Doppler Flowmeter, Department of Bioengineering, University of Iowa, Iowa City, Iowa). The pacing electrodes were attached to a trigger unit (Department of Bioengineering, University of Nijmegen, The Netherlands) and the occluder tube was connected to a 5-ml syringe. Both femoral arteries were dissected free. An 8F pigtail manometer catheter (Millar microtipped-catheter transducer SPC-780C) was introduced into the left femoral artery and positioned for simultaneous pressure recording in the left ventricle and the ascending aorta. A 5F left Judkins catheter was introduced into the right femoral artery and advanced into the ostium of the left main coronary artery. Electrocardiogram, left ventricular pressure and its first derivative, aortic pressure, and phasic and mean coronary blood flow velocity in the LCx were recorded on an eightchannel recorder (Hewlett-Packard).After intravenous infusion of 5 mg propranolol during 20 minutes to prevent disproportionate increase in heart rate, an initial dose of dipyridamole (0.75 mg/kg) was administered intravenously during 4 minutes to create maximal dilation ...

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Section: Discussionmentioning

confidence: 99%

Mean transit time for the assessment of myocardial perfusion by videodensitometry.

et al. 1990

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“…11 14,[21][22][23][24][25][26] It is assumed that this measurement allows determination of mean flow rates if the transit time is determined from the densograms as the difference between the mean appearance times. Because of the short measurement distance and the strongly pulsatile flow in the coronary artery system, this procedure is questionable.…”

Section: Discussionmentioning

confidence: 99%

Measurement of systolic and diastolic flow rates in the coronary artery system by x-ray densitometry.

Spiller¹,

Schmiel²,

Pölitz³

et al. 1983

Circulation

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The reliability of a modified videodensitometric and photodensitometric sampling technique for measuring phasic flow rates in the coronary artery system was examined. Electromagnetic flow measurements were performed in a circulatory model with continuous and pulsatile flow and intraoperatively in aortocoronary bypass grafts; cineangiograms were made simultaneously. Based on the front velocities of injected boluses of contrast medium, the densitometric measurement overestimated the electromagnetically measured flow systematically by about 20%. Systolic and diastolic flow rates in aortocoronary bypass grafts and coronary arteries determined from biplane cineangiograms in 34 patients generally revealed the typical pulsatile flow pattern familiar from electromagnetic and ultrasonic flow measurements. Flow velocities in unstenosed coronary arteries were nearly identical before and after branchings of the vessels, whereas the corresponding flow rates were higher in proximal than in distal segments. The identical flow velocities in different branches of the same vessel and the low variability of this parameter in different patients may be a suitable index of the effect of stenoses on coronary arterial blood flow. Circulation 68, No. 2, 337-347, 1983. THE SEVERITY of coronary artery disease is currently estimated by subjective evaluation of morphologic vessel abnormalities visualized by coronary angiography. Several methods have been used in the past to provide a quantitatiye means of measuring coronary blood flow in man, including indicator-dilution and radioisotope techniques as well as Doppler ultrasonic flow catheter measurements and densitometric evaluations of coronary angiograms. 1-8 Generally x-ray densitometry is based on the determination of the mean transit time of contrast medium. Mean transit time is defined as the difference between the mean appearance times of the contrast medium measured from the "densograms" (time function of x-ray density) at a proximal site and a distal site over the vessel.95In an attempt to avoid several methodologic difficulties inherent in this technique, we determined transit times from the fronts of the densograms (appearance From time) instead of the mean appearance time. The flow rates determined from the front velocities were compared with those flow values measured electromagnetically during the interval of the passage of the contrast medium. The measurements were performed in a model circulation and during coronary revascularization. From these examinations, the systematic deviation between electromagnetic and densitometric flow measurements was determined. In addition, the influence of the injected contrast medium on coronary artery flow was evaluated. The aim of this study was to establish the methodologic requirements for densitometric measurements of systolic and diastolic flow in the coronary artery system.

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“…The mean transit time after maximal vasodilation, corrected for changes in mean arterial pressure, allows the physiological result of coronary artery angioplasty, as shown by Pijls et al [18] , to be satisfactorily evaluated. For the first time in 1970, after extensive experimental studies in models and dogs [19,20] , we were able to measure blood flow by roentgendensitometry through the right coronary artery during routine coronary angiography in conscious man [21] . The method is based on the passage of a small contrast bolus through a proximal and a distal window placed over the artery, and the measurement of the mean transit time and the volume between both windows (Fig.…”

Section: Roentgendensitometrymentioning

confidence: 99%

“…These coronary flow and coronary reserve parameters under various conditions [37] indicate significant obstructions to blood flow and justify on-site clinical decision [19] ).…”

Section: Fractional Flow Reservementioning

confidence: 99%

Towards measurement of coronary blood flow in patients and its alteration by interventions

Rutishauser¹

1999

European Heart Journal

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Aim Several methods of measuring coronary blood flow in intact conscious man are reviewed, on the basis of personal contributions or the experiences of our teams. Methods and ResultsIt is important to distinguish between global, regional and transmural blood flow measurements. The advantages and limitations of the following methods are discussed: diffusible inert and radioactive tracers, dye dilution, roentgendensitometry, magnetic resonance imaging and contrast echocardiography. In interventional cardiology it is most important to be able to measure flow through single coronary vessels. Information on coronary artery Doppler velocity during vasodilation and at rest is less useful than the concept of fractional flow reserve. This is based on pressure measurements under maximal vasodilation to ascertain the presence of borderline flow-limiting lesions. This information is necessary in order to decide whether to proceed with angioplasty or not. ConclusionsThe historical design of percutaneous coronary angioplasty and beta-irradiation of coronary restenosis, established under the author's guidance, are put into perspective. The author pays tribute to many excellent colleagues who worked with him at

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Evaluation of Roentgen Cinedensitometry for Flow Measurement in Models and in the Intact Circulation

Cited by 79 publications

References 19 publications

Mean transit time for the assessment of myocardial perfusion by videodensitometry.

Mean transit time for the assessment of myocardial perfusion by videodensitometry.

Measurement of systolic and diastolic flow rates in the coronary artery system by x-ray densitometry.

Towards measurement of coronary blood flow in patients and its alteration by interventions

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