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Rede, uitgesproken bij de aanvaarding van het ambt van gewoon hoogleraar
in de klinische echocardiografie aan de faculteit der geneeskunde
van de Erasmus Universiteit te Rotterdam, op woensdag 24 oktober
198
Ultrasonic two-dimensional imaging of the heart with multiscan
The introduction of the prototype of an ultrasonic linear
array scanner in 1971, confronted us with a type of diagnostic
information which was different from conventional
cardiac imaging techniques. With the use of ultrasound,
cardiac structures were now displayed in a direct and
positive manner rather than as shadows or negative
impressions in contrast media as seen with X-ray and
angiocardiographic techniques. Imaging in multiple new
planes through the heart now became possible. These planes
were difficult or impossible to visualize With other
techniques. Therefore hardly any knowledge about the
anatomic information in these images existed. The major
aim of this thesis is to present the implementation into
the clinical practice of cardiology of the linear array
system which was developed at the Thoraxcenter in
Rotterda
Methodology, feasibility, safety and diagnostic accuracy of dobutamine stress echocardiography
Large numbers of patients referred for evaluation of chest pain are unable to perform adequate, diagnostic exercise testing. In these patients, dobutamine stress echocardiography (DSE) represents an alternative, exercise- independent stress modality. Apart from the ~5% of patients with an inadequate acoustic window, 10% of patients referred for this test have nondiagnostic (sub-maximal negative) test results. Serious side effects during or shortly after DSE are uncommon, with ventricular fibrillation or myocardial infarction occurring in ~1 of 2,000 studies. No deaths have been reported. On the basis of a total number of 2,246 patients, reported in 28 studies, the sensitivity, specificity and accuracy of the test for the detection of coronary artery disease (CAD) were 80%, 84% and 81%, respectively. Mean sensitivities for one-, two- and three-vessel disease were 74%, 86% and 92%, respectively. The sensitivity for detection of disease in the left circumflex coronary artery (55%) was lower, both compared with that for left anterior descending (72%) and right coronary artery disease (76%). The sensitivity of predicting multivessel disease by multiregion echocardiographic abnormalities varied widely, from 8% to 71%. In direct comparisons, DSE was superior to exercise electrocardiography and dipyridamole echocardiography and comparable to exercise echocardiography and radionuclide imaging. DSE is a useful, feasible and safe exercise-independent stress modality for assessing the presence, localization and extent of CAD
Quantification of transpulmonary echocontrast effects
Videodensity of left heart and right heart were studied after intravenous injection of increasing dosages of 0.01-0.02 and 0.04 mL/kg bodyweight of Albunex® in 10 healthy volunteers. The increase in videodensity in the left ventricle was always lower than in the right ventricle. Possible explanations are diffusion of gases caused by ambient pressures changes and change in microspheres distribution due to the sieving effect of the lung capillary bed. These phenomena were studied in vitro and were consistent with clinical observations. These limitations restrict a quantitative assessment of left heart echocontrast after intravenous injection
Assessment of Coronary Flow Reserve During Angioplasty Using A Doppler Tip Balloon Catheter. Comparison With Digital Subtraction Cineangiography
Intracoronary blood flow velocity measurements with a Doppler probe and the radiographic assessment of myocardial perfusion with contrast media previously have been used to investigate regional coronary flow reserve. In the present study we applied both techniques in the same patients to measure the immediate improvement in coronary flow reserve as a result of angioplasty. In addition we compared papaverine induced hyperemia with reactive hyperemia following transient transluminal occlusion of a major coronary artery. In 13 consecutive patients with a single proximal stenosis, coronary flow reserve was measured pre‐ and postangioplasty by digital subtraction cineangiography, while pre‐ and postangioplasty Doppler measurements before and after papaverine were obtained in the proximal part of the stenotic vessel. After the last transluminal occlusion, reactive hyperemia recorded with the Doppler probe was also compared to the coronary flow reserve measurement obtained during papaverine induced hyperemia. As a result of the angioplasty, coronary flow reserve measured with the radiographic technique (mean ± SD) increased from 1.1 ± 0.4 to 2.2 ± 0.4 (P < 0.001), while coronary flow reserve measured with the Doppler probe (mean ± SD) increased from 1.2 ± 0.3 to 2.4 ± 0.4 (P < 0.001). Pharmacologically induced hyperemia measured with the radiographic technique and the Doppler probe were linearly related (r = 0.91 with a SEE 0.3) and confirmed the reliability of the intracoronary measurements. Using these two independent techniques, coronary flow reserve immediately after angioplasty was found to be substantially improved but still abnormal. In addition, the magnitude of hyperemia induced by papaverine was comparable to the reactive hyperemia following transluminal occlusion, although the latter measurement was recorded with the angioplasty catheter still across the dilated lesion. (J Interven Cardiol, 1988:1:1) Copyrigh
Real-time quantification and display of skin radiation during coronary angiography and intervention
BACKGROUND: Radiographically guided investigations may be associated with excessive radiation exposure, which may cause skin injuries. The purpose of this study was to develop and test a system that measures in real time the dose applied to each 1-cm(2) area of skin, taking into account the movement of the x-ray source and changes in the beam characteristics. The goal of such a system is to help prevent high doses that might cause skin injury. METHODS AND RESULTS: The entrance point, beam size, and dose at the skin of the patient were calculated by use of the geometrical settings of gantry, investigation table, and x-ray beam and an ionization chamber. The data are displayed graphically. Three hundred twenty-two sequential cardiac investigations in adult patients were analyzed. The mean peak entrance dose per investigation was 0.475 Gy to a mean skin area of 8.2 cm(2). The cumulative KERMA-area product per investigation was 52.2 Gy/cm(2) (25.4 to 99.2 Gy/cm(2)), and the mean entrance beam size at the skin was 49.2 cm(2). Twenty-eight percent of the patients (90/322) received a maximum dose of 2 Gy. CONCLUSIONS: Monitoring of the dose distribution at the skin will alert the operator to the development of high-dose areas; by use of other gantry settings with nonoverlapping entrance fields, different generator settings, and extra collimation, skin lesion can be avoided
Safety, hemodynamic profile, and feasibility of dobutamine stress technetium myocardial perfusion single-photon emission CT imaging for evaluation of coronary artery disease in the elderly
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