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Biomedical subjects

P Thurn

Publications and source records attributed to P Thurn.

At least 19 recordsLinked to original sources

[Coronary calcification and luminal diameter in coronary disease (author's transl)].

Two hundred and thirty-six patients with coronary heart disease were examined by coronary angiography and laevo-cardiography. In 111 patients (47%) there was coronary artery calcification. Of these, 108 patients (97%) showed abnormal findings on the coronary angiogram; in 72 patients (67%) coronary stenosis was greater than or equal to 50% of the lumen. The severity of the stenoses increased with the amount of calcification. There were only three false positive findings and the presence of coronary calcification indicates coronary sclerosis with a high degree of probability. Fluoroscopy is the simplest and most sensitive method of examination and is of great value in the non-invasive investigation of coronary sclerosis.

Calcinosis

[Computer tomography in the diagnosis of aortic aneurysms (author's transl)].

The paper describes the diagnosis of ten thoracic, 20 abdominal and three peripheral arterial aneurysms by computer tomography. This permits a definite diagnosis by a non-invasive method, it defines the extent of the aneurysm and the amount of thrombus in the aneurysm; it permits recognition of a leak and is painless and without risk and can be performed rapidly. Morever, computer tomography provides an accurate control of growth of the aneurysm. In some cases a dissection can be recognised. The use of adequate quantities of intravenous contrast medium prevents any possibility of an incorrect diagnosis. The extent and density of the aneurysms, their lumina, clot and wall thickness, as determined by computer tomography are described. The values are compared with the aortic diameters of patients with normal vessels. The advantages of the method, compared with other procedures, are discussed and its role in the diagnosis of aortic and peripheral arterial aneurysms is described.

Aged

[Image characteristics of the computer tomograph (author's transl)].

In the present paper the images produced by spheres of varying diameter (d = 4,6,8,10 mm) embedded in a homogeneous substance of varying densities (H' = 3,48,93,137 Hounsfield units) as produced by computer tomography were studied. Measurements show that for each sphere diameter there is a minimum contrast between the substance of the sphere and its surroundings which must exist in order to show this sphere by computer tomography. It was also shown that the partial volume effect is of significance for the attenuation of the spheres. The effect of the position of the spheres within the slices to be imaged was studied. The results clearly indicate that in the investigation of small tissue changes in the body, the thickness of the slice and patient displacement should be kept as small as possible.

Absorptiometry, Photon

[Computer-cardio-tomography in idiopathic hypertrophic subvalvular aortic stenosis--a new contribution to non-invasive diagnosis (author's transl)].

The use of computer tomography as a non-invasive procedure in the diagnosis of idiopathic hypertrophic subvalvular aortic stenosis is described. Seven patients were investigated in whom the diagnosis had been confirmed by echocardiography and laevocardiography with pressure measurements. Details of the method are discussed and computer tomography and echocardiography are compared. The features of greatest differential diagnostic importance relating to asymmetrical septum hypertrophy are discussed.

Cardiomegaly

[Image properties of computer tomography. III. Measurements on homogenous materials. Relationship of attenuation and scatter to various parameters (author's transl)].

The present paper investigates the variations due to various parameters on the image of homogeneous materials as obtained with the Somatom CT scanner. Sugar solutions were used with concentrations equivalent to the absorption values of soft tissues. Because of quantum noise, attentuation at various points is not uniform, but is distributed in a Gaussian manner round a mean value. Using the Evaluskop it was possible to determine the degree of scatter. It was shown that, with increasing density of the material, the scatter increased and that this can be reduced by subjecting the tomogram to a smoothing process. It was further shown how the scatter depends on various parameters, such as thickness and dose. The amount of scatter in a tomogram is important in determining the density gradation which can be a achieved.

Absorptiometry, Photon

[Computer tomographic diagnosis of pericardial effusions (author's transl)].

Thirty patients with suspected pericardial effusions, or with cardiac enlargement of unknown cause were examined by computer tomography. In 19 cases a diagnosis of pericardial effusion or haematoma was made. All these cases were confirmed by echo cardiography or transthoracic puncture. The accuracy of computer tomography diagnosis did not depend on the aetiology, but could be increased by contrast enhancement. The computer tomographic criteria are enumerated and compared with those of echo cardiography. Examples of the most important differential diagnoses are discussed.

Adult

[A comparison of computer tomography and ultrasound for the demonstration of vessels in the abdomen and retroperitoneal space (author's transl)].

The value of computer tomography and ultrasound for demonstrating vessels in the abdomen and retroperitoneal space was compared. The methods were equal in their ability to demonstrate the major vessels situated centrally, but computer tomography proved better at differentiating arteries and veins situated peripherally. On the other hand, sonography proved a simple means of differentiating intrahepatic vascular structures.

Abdomen

[Computer-Cardiotomography (author's transl)].

Based on our first 200 investigations computed tomography of the heart is demonstrated as a new non-invasive roentgenography on typical examples and compared with the findings of the conventional roentgenogram. With the present technology the following indications for computed tomography of the heart seem to be reasonable: Calculation of size and volume of the cavities of the heart; intracavitary space occupying lesions (tumor, thrombus): demonstration of the thickness of the ventricular wall and ventricular septum and their changes caused by hypertrophy, myocardial infarction or septal defect; demonstration of aortic and ventricular aneurysm; demonstration of pericardial effusion, pericardial tumor, pericardial cyst of lipoma.

Cardiomegaly

[Extension of thoracic roentgen diagnosis by computer tomography (author's transl)].

In 400 examinations of the thorax results of computer tomography were compared with respective pa chest films and conbentional tomograms. In the peripheral areas of the lung, interstitial parenchymal alterations and metastases were better visualized by CT. The size of central bronchial carcinomas and space-occupying lesions of the thoracic wall can be determined with greater accuracy by CT. Primary tumors, lymphnode enlargement and vascular alterations can be differentiated and localized more precisely by CT. The size of the heart chambers, intracavitary tumors as well as septal and myocardial wall thickness can be determined non invasively.

Aortic Aneurysm

[Mitral stenosis on conventional radiographs. II. The relationship between pulmonary venous and arterial hypertension, their haemodynamic parameters and calcified mitral valves (author's transl)].

In the second paper, the relationship between pulmonary venous and arterial hypertension and calcification in the mitral valve is analysed statistically and its patho-physiological significance discussed. In one hundred cases of mitral stenosis the left atrium, as seen on the lateral projection, was always enlarged, but its size was independant of atrial pressure or the pressure gradient across the mitral valve. Apart from pulmonary fibrosis and haemosiderosis, the abnormal findings increased with increasing mean atrial pressure. Pulmonary-arterial mean pressure of more than 30 mmHg was found particularly in the presence of mitral valve calcification (94%). Calcification of the valve is the most important and reliable indicator for evaluating the severity of the stenosis.

Adult

[The diagnostic value of kymography in aortic isthmus stenosis (author's transl)].

The value of kymography was studied in 133 patients in whom a coarctation had been demonstrated angiographically, operatively or pathologically; its value was compared with conventional radiographic examinations. The difference in pulsation between the pib notching, dilatation of the ascending aorta and increased size of the left ventricle on plain films make it possible to diagnose an haemodynamically significant coarctation without any invasive methods. In 124 haemodynamically significant coarctations (93%), the kymogram showed increased pulsation of the dilated left subclavian artery. In nine haemodynamically insignificant or mild coarctations (7%), this sign was absent. Since the radiographic signs are to some extent reversible, it is possible to evaluate the results of surgery by plain chest films and the kymogram.

Adolescent

[Quantitative functional analysis of the left ventricle in coronary heart disease. An evaluation of current methods. II. Correlation of results. Global and regional contractility parameters (author's transl)].

In the first part of the present paper, the basic methods for quantitative angiocardiography are described. In the second part, a variety of results are tabulated and discussed, derived from selective coronary arteriography, laevocardiography, left ventricular pressure measurements and heart size as seen on conventional chest X-rays. Various correlations have been derived from these. It was not possible to find an quantitative relationship between coronary sclerosis and myocardial function. The reason for this depends on the fact that the parameters derived from laevocardiography represent integrated global function. The significance of regional contractility is stressed.

Angiocardiography

[Computer tomographic demonstration of an intramuscular haematoma in haemophilia (author's transl)].

Anatomical localisation of intramuscular haematomas can be achieved more accurately by computer tomography than by clinical examination in conjunction with conventional radiography. Computer tomography is able to demonstrate fresh haematomas before they become diagnosable clinically, and before secondary changes, such as calcification or bone erosions, make them visible on conventional radiographs. In this way the diagnosis is made more certain and the choice between conservative or surgical treatment is simplified. Ther period of treatment with clotting factors can, in some cases, be shortened as a result of serial examinations by computer tomography.

Diagnosis, Differential

[Fast computer tomography for investigation of the heart--"computer cardiotomography". Methods and early results (author's transl)].

The early results in the investigation of normal and pathological hearts using fast computer tomography are presented. By means of tomographic sections of cadaver hearts, it has been shown that it is possible to distinguish the ventricular cavities and individual cardiac walls by this non-invasive method. Changes in volume of the ventricles and atria due to various forms of stress are easily distinguishable. Myocardial scars can be distinguished from other circumscribed myocardial defects. The particular advantages of this method, which is non-invasive, painless and easily repeatable, do not need to be stressed. The technique adds a significant dimension to previously available non-invasive diagnostic methods, such as ultrasound echo-cardiography.

Aortic Valve

[Computer cardio-tomography for tumours of the left atrium (author's transl)].

The role of computer tomography in the diagnosis of cardiac tumours was demonstrated by three patients with myxomas of the left atrium. After intravenous contrast administration these tumours appeared as relatively translucent space-occupying lesions on the computer tomograph. The invasive method of angio-cardiography is unlikely to provide any additional information concerning tumour size or localisation when compared with non-invasive computer tomography or echo cardiography.

Female

[Comparison between computer tomography and ultrasound in abdominal and renal growing and displacing processes (author's transl)].

The advantages and limitations of both methods are analyzed and compared. The comparison is effected on the basis of the present standard of equipment. The results obtained with both methods are demonstrated by means of the example of frequent epigastric diseases. Despite the still limited number of patients examined simultaneously both by ultrasound and computer tomography, it seems that the sensitivity of both methods in case of growing and displacing processes in the epigastric or renal regions, does not differ greatly. A comparison of the specificity of both methods will be effected only after a large number of patients has been examined by both methods at the same time.

Abdominal Neoplasms

[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