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Biomedical subjects

C Winkler

Publications and source records attributed to C Winkler.

At least 163 records · Page 9Linked to original sources
PubMed1978

[Quantitative gated radionuclide cine cardiography. I Technical basis and methods (author's transl)].

Scintigraphic evaluation of the heart function is performed by means of sequential camera scintigraphy following i.v. injection of a 99mTc albumin bolus. The first tracer passage is registered during 30 seconds. About 10 minutes later--after equilibration of the tracer in the blood pool--volume curves of the left ventricle are recorded from a series of about 500 heart cycles. The principles of a computer program which has been developed for this method are described and discussed in detail.

Computers↗
PubMed1978

[Functional scintigraphy during contraction of the left ventricle. II. Evaluation of background correction (author's transl)].

During evaluation of cardiac function using 99mTc human serum albumen (functional scintigraphy during contraction of the left ventricle), it is necessary to take account of the background radiation which is derived from the lungs and great vessels overlying the heart. Only after correction of the background radiation is it possible to evaluate the severity of various types of cardiac insufficiency; this can be obtained by integrating the impulse during systole and subtracting this from the impulse rate over the left ventricle during a complete cardiac cycle. Apart from the background correction derived from the systolic-diastolic variation, it is necessary to obtain adequate resolution by examining 100 frames per second, an adequate picture matrix (4-K) in order to obtain adequate spacial resolution and accurate measurements of systole and diastole. The latter should be obtained not from the E.C.G., but directly from the volume curve of the left ventricle as determined by the isotope method.

Electrocardiography↗
PubMed1978

[The effect of urinary obstruction on the results of catheterless divided 131I hippuran clearance studies (author's transl)].

During catheterless renal 131I Hippuran clearance studies, the function of each kidney can be calculated from the area integral, which is derived from the total body curve and to segments of phase II of each nephrographic curve measured for 120 seconds after the injection. For this it is assumed that the course of this phase depends entirely on the function of the renal parenchyma and is not affected by other factors such as urinary obstruction. During investigations of obstructed kidneys, considerable discrepancies were found repeatedly between clearances calculated by this method and the operative findings of a paper thin renal parenchyma of the kidney in question. In two cases it has been shown for the first time that there is an unexpected and surprising change in phase II. It follows that urinary obstruction falsifies the results of 131I Hippuran clearance tests, leading to an overestimate of the function of the obstructed kidney.

Humans↗
PubMed1978

[Functional scintigraphy during contraction of the left ventricle. III. Findings in patients with coronary heart disease (author's transl)].

Left ventricular volume curves were measured by a noninvasive technique after equilibration of 99m TC human serum albumin in 27 patients with angiographically proven coronary heart disease. Compared with normals, patients with coronary insufficiency showed a significant reduction in the ejection fraction and of maximal emptying and filling times of the left ventricle during rest. In mildly affected patients with normal ejection fractions, maximal filling was already reduced in keeping with the well known loss of compliance of the left ventricle due to coronary disease.

Cardiac Volume↗
PubMed1978

[Studies on renal clearance measurements by nuclear medicine methods (author's transl)].

Two mathematical models are employed to describe and interpret the time-activity course in the human body outside the reno-vesical compartment of a tracer that has been injected intravenously by the single-shot method and is excreted via the kidneys. From the results a method is derived which permits a practical determination of total clearance. The individual clearance of each kidney is calculated using a simplified method of background (EPA) correction.

Glomerular Filtration Rate↗
PubMed1978

[Myocardial perfusion scintigraphy - methods and fundamentals (author's transl)].

Myocardial perfusion studies with labelled particles make a detailed analysis of the distribution of myocardial perfusion possible. Methodical and physiological fundamentals are described and the reliability of the method is shown by double radionuclide imaging. LAD-stenoses (greater than 70%) show a decreased activity in the distal areas of the LAD (on the average 36,5 +/- 10,3% in contrast to 59 +/- in normals). Mean local activity is 14,9 +/- 1,8% within scars. Scars and hemodynamically effective stenoses can be imaged with high sensitivity. Total defects (smaller than 15% of the activity maximum) correspond to a scar. A moderate reduction of uptake (15--50% of the activity maximum) does not allow any differentiation between scar and reversible diminution of perfusion.

Coronary Circulation↗
PubMed1977

[Abnormal myocardial blood flow pattern after non-transmural infarction (author's transl)].

While coronary angiography was within normal limits in three patients with recurrent severe attacks of angina and non-transmural postero-lateral wall myocardial infarction, myocardial perfusion scintigraphy demonstrated an abnormal distribution pattern. In addition to recanalised thrombosis, embolism or spasm, abnormalities in the microcirculation are possible causes of the discrepancy between the coronary arteriogram and the scintigram. Myocardial perfusion scintigraphy is of particular diagnostic significance in this group of patients with coronary heart disease but normal coronary angiography. Treatment in the presence of this finding consists of administration of platelet-aggregation inhibitors.

Adult↗
PubMed1977

[Compromized myocardial perfusion in arrhythmias (author's transl)].

In 7 patients with arrhythmias of various origin the myocardial scintigram displayed either a diffuse or circumscript defect of the perfusion. The coronary arteriogram was normal in all patients. The localized defect of the perfusion in 2 patients was in the region of the upper part of the interventricular septum. Both had a left bundle brunch block. A correlation between the perfusion defect and the electrophysiological abnormality seems probable. The perfusion defect in one of the patients is most probably caused by a previous myocarditis followed by fibrous changes. In the other 6 patients the cause for the perfusion defect is not obvious. A history of myocarditis is missing. The presence of "small vessel disease" in those patients has however to be considered. Our results point to the relation between an abnormality of the microcirculation and arrhythmias in younger patients.

Adult↗
PubMed1977

[Current radionuclear methods in the diagnosis of regional myocardial circulation disorders].

Among nuclear medical diagnostic procedures a distinction can be made between non-invasive and invasive methods. The non-invasive methods serve either to image the still viable myocardium ("cold spot" technique) or for direct visualization of recently infarcted myocardial tissue ("hot spot" technique). These methods have the advantage of simple handling and good reproducibility. Side effects and risks are thus far unknown. Improvement of local dissolution should be aimed at in the future and wound greatly increase diagnostic and topographic security. The invasive procedures always require catheterization of the coronary arteries. This is the reason why they can be performed only with coronary arteriography. The Xenon "wash out" technique permits, with some restrictions, quantitative measurement of the regional flow rate. The "inflow technique" permits determination of perfusion distribution. The possibilities of the "double-radionuclide" scintigramm are discussed. For measurement of activity distribution, sationary detectors are generally preferred. In the case of the time-activity curves with the Xenon "wash out" technique, single detectors offer certain advantages.

Blood Flow Velocity↗
PubMed1977

[Sequential hepato-splenic scintigraphy for measurement of hepatic blood flow (author's transl)].

The arterial and portal components of total liver blood flow were determined quantitatively in 31 patients by means of a new, non-invasive method. Sequential hepato-splenic scintigraphy has been employed, using a scintillation camera linked to a computer system. In normals, the proportion of portal flow was 71%, whereas in patients with portal hypertension it averaged 21%. Our experience indicates that the procedure can be of considerable value in the pre-operative diagnosis and postoperative follow-up of portal hypertension.

Adolescent↗
PubMed1977

[Hepatobiliary scintigraphy with (99m)Tc-diethyl-IDA (author's transl)].

A short description of the pharmacology and kinetics of (99m)Tc-diethyl-IDA is given; our experience with this new radiopharmaceutical as a functional test of liver and bile ducts is illustrated by a number of typical examples. The ability to use increased activity together with high resolution "low energy" detectors provides excellent detail recognition in the hepato-biliary system. In addition, sequential scintigraphy with its resulting time-activity curves provides information regarding the function of the hepatocytes. The significance of hepatobiliary scintigraphy is its ability to distinguish between parenchymal and obstructive jaundice.

Acetanilides↗
PubMed1977

[Sequential hepato-splenic scintigraphy with 99mTc-pertechnetate in experimental post-hepatic block (author's transl)].

Using baloon catheters in the inferior vena cava, post-hepatic blocks were produced in experimental animals. Subsequent liver perfusion scintigraphy showed marked reduction in portal flow. The significance of these findings in the diagnosis of the Budd-Chiari syndrome and its differentiation by scintigraphy from an intrahepatic block in cirrhosis of the liver is discussed.

Animals↗
PubMed1977

Pertussis vaccine: reactivity in animal and man.

Clinical investigation of the reactivity of diphtheria-tetanus-pertussis (DTP) vaccines is a routine control in the GDR. This paper shows the results of the clinical control of 26 batches of DTP vaccine in comparison with animal tests (weight-gain-test, histamine-sensitizing test, dermonecrotic test). The animal tests gave no support to innocuity. The batches were tested on 427 children and passed the requirements for reactivity. After a storage for 2 years the control of 3 different batches was repeated. Two of them showed side reactions in children in spite of the fact that the results of the weight-gain test did not change.

Animals↗