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Biomedical subjects

K Lackner

Publications and source records attributed to K Lackner.

At least 19 recordsLinked to original sources
PubMed1992

Direct measurement of spin-lattice relaxation times of phosphorus metabolites in human myocardium.

T1 values of phosphorus metabolites visible in human cardiac 31P-MR spectra were determined in 12 volunteers at 1.5 T. Consecutive spectra were acquired with varying pulse repetition time (TR) from 1.6 to 24 s; volume selection was achieved with ISIS. T1's of creatine phosphate (CP), [gamma-P], [alpha-P], and [beta-P]ATP, 2-3 diphosphoglycerate, and phosphodiesters were 6.1 +/- 0.5, 5.4 +/- 0.5, 5.5 +/- 0.5, 5.8 +/- 1.0, 7.6 +/- 1.0, and 5.0 +/- 1.0 s, respectively. CP/ATP ratios showed little change with varying TR; linear regression of CP/ATP vs TR was of borderline significance (r = 0.28, P = 0.06). T1's for CP and ATP were also determined in standard solution (20 mM CP, 10 mM ATP) yielding T1CP of 8.7 +/- 0.2 and T1[gamma-P]-ATP of 9.9 +/- 0.7 s. Thus, T1's for CP and ATP were similar at 1.5 T in both human heart and standard solution. In human cardiac 31P-MR spectra, CP/ATP ratios may need little correction for partial saturation.

2,3-Diphosphoglycerate↗
PubMed1992

[The value of digital subtraction sialography compared to conventional sialography, salivary gland sonography and surgical findings].

In a prospective study DSA sialography, conventional sialography (100mm technique) and sonography of the salivary glands were performed in 124 patients. The results of imaging could be correlated with those of operation and/or histology in 70 patients. Performing sialography in only one projection DSA sialography is superior to the conventional technique. The results of DSA are equivalent to those of conventional sialography in more than one projection. DSA sialography is the method of choice demonstrating salivary calculi, whereas sonography is superior to DSA sialography in the detection of tumors. In the diagnosis of chronic inflammation of the salivary glands DSA is slightly superior to the other imaging modalities.

Adolescent↗
PubMed1992

[Pharmacokinetics of gadolinium-DTPA in chronic renal insufficiency requiring dialysis].

MRT with gadolinium-DTPA (0.1 mmol/kg body weight) was performed in 10 patients with renal insufficiency requiring dialysis and the clearance of gadolinium-DTPA was studied. After 3 dialysis on 3 successive days more than 97% of the initial concentration of gadolinium-DTPA had been eliminated. Average half-life was 1.87 hours. There were no side effects in any of the patients. Close laboratory observation of liver function showed no significant changes during the period of study. No contra-indication for the use of this contrast medium in patients with renal insufficiency requiring dialysis was found during this study.

Adult↗
PubMed1992

[The determination of myocardial mass by cardiac magnetic resonance tomography. The effect of section alignment and section distance].

The effect of section alignment and distance in volumetric determination of myocardial mass by means of cardiac magnetic resonance imaging (MRI) was studied in 19 isolated pig hearts. Double angulated views taken through the short axis of the heart with a slice thickness of 10 mm and slices at a distance of 0 mm, 1 mm, 3 mm and 5 mm produced accurate left ventricular measurements with cardiac MRI. Measurements in the long axis of the heart resulted in a marked underestimation of myocardial mass; depending on slice intervals, there was an error between 13% and 20%. In vivo measurements in 35 subjects confirmed the effect of section alignment. Measurements in the long axis of the heart produced results of 139.9 +/- 31.7 g, significantly less than measurements in the short axis of the heart of 157.8 +/- 32.3 g.

Adult↗
PubMed1992

[The direct measurement of the spin-grid-relaxation times of phosphorus metabolites in the human myocardium].

The T1 relaxation times of the phosphorus metabolites in human heart muscle measurable by 31P-MR spectra were determined in 12 individuals using a 1.5 Tesla system. Several spectra were recorded consecutively with a pulse repetition time of 1.6 s to 24 s. The T1 times of creatine phosphate (CP), of gamma-, alpha-, beta-adenosintriphosphate (ATP), 2,3-diphosphoglycerate (2,3-DPG) together with anorganic phosphate) and phosphodiester (PDE) showed mean measurements of 6.1 +/- 0.5, 5.4 +/- 0.5, 5.0 +/- 0.5, 5.8 +/- 1.0, 7.6 +/- 1.0, and 5.0 +/- 1.0 s (M +/- SE). The accuracy of the ISIS technique was tested with a special phantom. T1 times were also measured in standard solutions (20 mM CP, 10 mM ATP); CP was 8.7 +/- 0.2 s and gamma-ATP was 9.9 +/- 0.7 s. Corrections for partially saturated 31P-MR spectra--at least for CP/ATP ratios--are relatively small.

2,3-Diphosphoglycerate↗
PubMed1992

31P magnetic resonance spectroscopy in dilated cardiomyopathy and coronary artery disease. Altered cardiac high-energy phosphate metabolism in heart failure.

BACKGROUND: The purpose of this work was to further define the value of cardiac 31P magnetic resonance (MR) spectroscopy for patients with coronary artery disease and dilated cardiomyopathy. METHODS AND RESULTS: Blood-corrected and T1-corrected 31P MR spectra of anteroseptal myocardium were obtained at rest using image-selected in vivo spectroscopy localization, a selected volume of 85 +/- 12 cm3, and a field strength of 1.5 T. Nineteen volunteers had a creatine phosphate (CP)/ATP ratio of 1.95 +/- 0.45 (mean +/- SD) and a PDE/ATP ratio of 1.06 +/- 0.53; in four patients with left anterior descending coronary artery (LAD) stenosis, six patients with chronic anterior wall infarction, and four patients with chronic posterior wall infarction, CP/ATP and phosphodiester (PDE)/ATP ratios did not differ from those in volunteers. Twenty-five measurements of 19 patients with dilated cardiomyopathy yielded a CP/ATP of 1.78 +/- 0.51 and a PDE/ATP of 0.98 +/- 0.56 (p = NS versus volunteers). When these patients were grouped according to the severity of heart failure, however, CP/ATP was 1.94 +/- 0.43 in mild (p = NS versus volunteers) and 1.44 +/- 0.52 in severe DCM (p < 0.05), respectively. No correlation was found between CP/ATP and left ventricular ejection fraction or fractional shortening, but correlation of CP/ATP with the New York Heart Association (NYHA) class was significant (r = 0.60, p < 0.005). Six patients with dilated cardiomyopathy were studied repeatedly before and after 12 +/- 6 weeks of drug treatment leading to clinical recompensation with improvement of the NYHA status by 0.8 +/- 0.3 classes. Concomitantly, CP/ATP increased from 1.51 +/- 0.32 to 2.15 +/- 0.27 (p < 0.01), whereas PDE/ATP did not change significantly. CONCLUSIONS: Cardiac high-energy phosphate metabolism at rest is normal in LAD stenosis and chronic myocardial infarction in the absence of heart failure. The CP/ATP ratio has low specificity for the diagnosis of dilated cardiomyopathy. However, CP/ATP correlated with the clinical severity of heart failure and may improve during clinical recompensation.

Adult↗
PubMed1979

[Demonstration of left-ventricular contraction anomalies with the two-dimensional sector-scanner (author's transl)].

Echocardiographic findings were compared with those obtained by cardiac catheterisation in 134 patients. Echocardiography was performed in the standard plane of the long and short axes, as well as from the cardiac apex. After dividing the left ventricle into several segments wall movement was measured in them and compared with those obtained by ventricular angiography in the right and left anterior oblique positions. It was found that in patients with left-ventricular aneurysm, proven by left ventricular angio, there was complete conformity with regard to localisation and extent of the aneurysm between the two methods of investigation. In this group 79% of the demonstrated segments could be adequately assessed and, in 91%, agreed with the radiological findings. In the group of patients without aneurysm only 68% of the segments could be adequately assessed, and 77% correctly assessed wall movement when compared with the laevocardiogram. Tracing recorded from the cardiac apex gave especially good results in demonstrating the ventricle and its segments.

Adult↗
PubMed1979

[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↗
PubMed1979

[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↗
PubMed1979

[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↗
PubMed1979

[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↗
PubMed1979

[Computer tomographic demonstration of lymph node metastases from malignant testicular tumours. A comparison of lymphography and computer tomography (author's transl)].

Lymphography and computer tomography was performed on 64 patients with malignant testicular tumours in order to demonstrate lymph node metastases. In 60 patients it was possible to confirm the findings by surgery. In 43 patients there was agreement between the findings of the computer tomogram and the lymphogram. In 39 of these patients lymph node metastases had been demonstrated, in three there was a false negative and in one a false positive. Amongst the patients in whom there was a descrepancy between the two types of examination, the CT findings were confirmed histologically in twelve, and the lymphographic findings in nine. In 12.5% CT added significant additional information. Accuracy of lymphography was 73% and of computer tomography 80%. Specificity for each examination was 79%.

Adult↗
PubMed1979

[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↗
PubMed1979

[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↗
PubMed1979

[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↗