Zien wat je niet ziet

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

Cardiac catheterization under echocardiographic control in a pregnant woman

A 22 year old woman had signs of rheumatic mitral and aortic valve disease early in pregnancy. Cardiac catheterization was performed during her third month of pregnancy under two-dimensional echocardiographic control without the use of ionizing radiation. Severe mitral stenosis with mild aortic stenosis was found. Five cubic centimeters of 5 percent dextrose in water were injected by hand to obtain left ventriculograms and supravalvular aortograms of sufficient quality to diagnose valvular regurgitation. The use of "echo-catheterization" may have significant advantages in selected clinical situations

Videodensitometric processing of contrast two-dimensional echocardiographic data

We developed a computer program to analyze videodensity changes due to contrast appearance within a given operator-designated rectangle using two-dimensional echocardiograms previously recorded on videotape. Videodensity curves have been obtained from two-dimensional echocardiographic recordings in 14 patients after a total of 32 injections of 5% dextrose solution into the left ventricle during cardiac catheterization. The resulting videodensity vs time curves have some characteristics of indicator-dilution curves. The decay phase of these curves is largely mono-exponential. Potential clinical applications of this technique in measurement of ejection fraction, cardiac output and shunt quantification are discussed, as well as some potential limitations