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Biomedical subjects

F Bitter

Publications and source records attributed to F Bitter.

At least 37 records · Page 2Linked to original sources
PubMed1981

[Quantitative left ventriculography: comparative investigations in normal patients (author's transl)].

In 17 patients with no demonstrable cardiac disease, analysis of the ventriculogram with respect to regional wall motion was performed. These normal patients formed the basis for establishing the normal ranges for 6 different methods of regional wall motion analysis (3 chord, 2 radial, 1 area). In each method, analysis of regional shortening showed a Gaussian distribution. The normal range of a segment was defined as the mean +/- 2 standard deviations, hence comprising 95% of normals. Comparing our 6 normal ranges with the ranges as initially described by their respective authors, the general shape of our curves was largely in agreement with the original curves. In detail, the amount of regional shortening showed some discrepancies, and only our normal range curve, calculated according to the method of Leighton, was highly comparable to the original range of the author, as well as to the one of Brower. Reasons for the discrepancies using other methods may be accounted for by different catheter conditions, different patient material and a subjective variation in delineating the contours of diastole and particularly of systole. It is concluded that normal ranges of a method for wall motion analysis cannot be applied directly from the literature without their prior verification under the special conditions of the angiographic technique and evaluation used.

Heart Ventricles↗
PubMed1981

[Assessment of left ventricular regional function by means of radioactive isotopes (author's transl)].

Extensive analysis of heart function by scintigraphy yields global parameters of ventricular volumes and their changes during the heart cycle (ejection fraction, enddiastolic and endsystolic volumes, velocity of contraction and relaxation). Additionally, information regarding localized disorders of wall motion may be obtained in a qualitative and quantitative manner by the parameters "phase" and "amplitude". These parameters can be computed from regional time-activity curves by Fourier analysis. The radionuclide ventriculogram at rest is suitable for the detection and follow-up of asynergies caused by acute and chronic infarction. In can also be used as a method of distinguishing between reversible and irreversible asynergy by therapeutical intervention (intervention ventriculography). Abnormalities of regional wall motion which develop during exercise may indicate hemodynamically relevant coronary artery stenoses.

Cardiac Output↗
PubMed1980

Assessment of the left ventricular function with the nuclear stethoscope.

The evaluation of the left ventricular function with the "Nuclear Stethoscope" was performed on 27 patients with heart diseases. The reproducibility of the measurements was good. Repetitions of EF, ER and EDV estimations yielded errors of 2.63%, 1.45% and 0.31%, respectively. The comparison with the results of camera ventriculography showed a good agreement of EF, contraction velocity parameters and relaxation velocity parameters, with a cor. coeff. of greater or equal to 0.750. An especially high correlaton was found between the NS EF and NS ER (r = 0.968). It was concluded that the "Nuclear Stethoscope" provides a reliable evaluation of left ventricular function.

Adult↗
PubMed1980

[Radionuclide ventriculography as a special case of functional scintigraphy (author's transl)].

Computer processed dynamic scintigraphy (CPDS) (Funktionsszintigraphie), as developed 15 years ago essentially in the German Cancer Research Center (Institute of Nuclear Medicine), Heidelberg, shows limitations with regard to temporal spatial resolution. Under fixed count rate conditions, temporal resolution can only be improved at the expense of spatial resolution. The adverse implications of this inverse relationship may be overcome by the use of trigger techniques, resulting in an improvement in statistical information. The strict application of principles as developed in CPDS in gated blood pool procedures leads to parametric scans (functional imaging) displaying optimal utilisation of available information and presentation of regional wall motion abnormalities.

Evaluation Studies as Topic↗
PubMed1978

[Radionuclide ventriculography. I. Fundamentals and methods (author's transl)].

Using local time activity curves parameters are calculated which depend on the local wall motion of the heart cavities. These functional parameters allow the determination of the contours of the heart cavities and the assessment of segmental wall motion disorders. The left ventricular ejection fraction has been calculated by enddiastolic and endsystolic counts using a method which takes into account background inhomogeneity.

Electrocardiography↗
PubMed1978

[Radionuclide ventriculography. II. Clinical results--parameters of global ventricular function (author's transl)].

The ejection fraction as determined by gated blood pool studies was compared with the ejection fraction as evaluated by the following conventional methods: 1) biplane cineangiography employing the Simpson rule. Correlation was r = 0.805 (n = 25); 2) the same patients using the area-length method (r = 0.88, n = 25); 3) monoplane cineangiography using the method of Greene et al. (5) (r = 0.86, n = 35). In 20 patients the maximal contraction velocity as evaluated by radionuclide ventriculography was compared with the mean systolic ejection rate. The observed correlation was weak (r = 0.62, n = 20); however, it should be noted that the radionuclide method determines the maximum contraction velocity whereas cinceangiography measures an average value over the whole systole.

Cineangiography↗
PubMed1978

[Radionuclide ventriculography. III. Clinical results--parameters of regional wall motility (author's transl)].

Radionuclide ventriculography and cineangiography were performed in 62 patients with suspected coronary artery disease. Regional wall motility irregularities could be demonstrated in 97% of those patients who revealed an irregularity in the cineangiogram. Two small scars of the posterior myocardial wall escaped detection. The sensitivity of the radionuclide ventriculography was 97%, the specificity was 80%, 4 patients with normal cineangiography showed small irregularities in the radionuclide ventriculogram. 70 patients with infarction revealed wall motility irregularities in 90%, whereas perfusion defects could be detected by thallium scintigraphy in 66% (young and old infarctions).

Cineangiography↗
PubMed1977

[Regional myocardial motility as evaluated by analysis of "gated blood pool" data (author's transl)].

Cyclic precordial variations of radiation after i.v. administration of 15 mCi 99mTc-HSA correspond to cyclic volume changes of ventricular volumes of the heart. The "gated blood pool procedure" yields reliable data. Extensive analysis of these data results in subsequent information concerning left ventricular myocardial behaviour: 1. extent of the regional myocardial contraction 2. homogeneity of the contraction 3. regional contraction velocity 4. regional relaxation velocity. Four parametric scans present the distribution of each one of those parameters within the heart. Gated blood pool data have been compared with angiographic data. Reliability of those parameters obtained by extensive analysis of the gated blood pool data could be proven.

Adult↗
PubMed1976

[Functional scintigraphic radiospirometry. First clinical results in patients with lung diseases].

First clinical results of patients with diseases of the lungs. The previous experiences on patients with diseases of the lungs reveal that the regional function diagnostics of the lungs may be extended and improved by functional scintigraphic radiospirometry. Because of the determination of regional lung volumes restrictive lung diseases can be differentiated and analysed more exactly than it has been possible before by the examinations of perfusion and ventilation alone. A further advance of the determination of lung volume is that the question of functional operability can be cleared up exactly. In our opinion the routine use of the functional scintigraphic radiospirometry is justified. A contraindication for this kind of examination should only be pregnancy.

Adult↗
PubMed1976

[Segmental wall movement of the left ventricle in healthy persons and myocardial infarct patients studied by a catheter-less nuclear medical method (camera-cinematography of the heart)].

Camera-Kinematography is a nearly noninvasive method to investigate regional motion of the myocard, and allows evaluation of the function of the heart. About 20 min after injection of 15-20 mCi of 99mTC-Human-Serum-Albumin, when the tracer is distributed homogenously within the bloodpool, data acquisition starts. Myocardial wall motion is represented in an appropriate quasi three-dimensional form. In this representation scars can be revealed as "silent" (akinetic) regions, aneurysms by asynchronic motion. Time activity curves for arbitrarily chosen regions can be calculated and give an equivalent for regional volume changes. 16 patients with an old infarction have been investigated. In fourteen cases the location and extent of regions with abnormal motion could be evaluated. Only two cases of a small posterior wall infarction did not show deviations from normal contraction pattern.

Cineradiography↗
PubMed1975

[Scintigraphic radio-spirometry. Methods and indications].

Scintigraphic radio-spirometry combines conventional spirometry with the advantages of a functional isotope technique, thereby providing a clinically useful method for the study of pulmonary function. The advantage of the method consist principally in the ability to estimate physiological values separately for the two lungs, and also for selective portions of each lung. The apparatus, method and quantitative evaluation of the results are discussed in detail and the method is critically evaluated. Indications for radiospirometry are given.

Air↗
PubMed1975

[Camera-cinematography of the heart (author's transl)].

By "camera-cinematography" of the heart, we mean an isotope method which permits detailed observation of cardiac mechanics without the use of a catheter. All that is necessary is an intravenous injection of 10 to 15 mCi 99mTc human serum albumen followed after ten minutes by a five to ten minute period of observation with a scintilation camera. At this time the isotope has become distributed in the blood. Variations in the precordial impulses correspond with intra-cardiac changes of blood volume during a cardiac cycle. Analysis of the R-wave provides adequate information of cyclical volume changes in limited portions of the heart. This is achieved by a monitor with a pseudo-3-dimensional display; contraction and relaxation of the myocardium can be shown for any chosen longitudinal or horizontal diameter of the heart. Our programme allows simultaneous presentation of the movement of any point on the myocardium as a time-activity curve. The method is recommended as an addition to chest radiography, heart screening or cardiac kymography before carrying out cardiac catheterisation.

Cardiac Output↗