Search PubMed⌕ Search

Biomedical subjects

R Felix

Publications and source records attributed to R Felix.

At least 757 records · Page 42Linked to original sources
PubMed1984

[Diagnosis of renovascular hypertension by intravenous digital subtraction angiography and renal sequential scintigraphy].

Intravenous digital subtraction angiography (DSA) and 131J-hippuran clearance (NSS) were evaluated in 113 patients, both methods were made as screening tests for renovascular hypertension. In 9 examinations DSA was not diagnostic, in 18 patients arterial wall lesions were found. The dynamic renal imaging with hippuran showed alterations in 86 patients, 2 patients with renal arterial stenosis had normal findings. Combination of both methods yields good results in estimation of the haemodynamic significance of a renal arterial narrowing.

Adult↗
PubMed1984

[Focal liver diseases. Comparative study of computed tomography, conventional ultrasound and the automated multisector scanner (Octoson)].

A comparative study, on 251 patients, between CT, Octoson and conventional ultrasound, established that CT (with angio-CT) had the highest rate of sensitivity (95.86%). The Octoson examination had a higher sensitivity (92.58%) than the conventional ultrasonic examination (82.64%). This result is achieved because superficial and subdiaphragmatic metastases, which lie in the depth of the liver, are better presented by the Octoson than with a mechanical sector scanner. Superficial metastases need to be presented with a water-path transducer for superficial lesions and subdiaphragmatic metastases with a wide range focus transducer. These areas can also be accurately shown on scanners with a dynamic transducer. The specificity of these three methods lies between 90 and 96%.

Echinococcosis, Hepatic↗
PubMed1984

[Cerebral circulatory disorders--elucidation by intravenous digital subtraction angiography and computed tomography].

In 110 patients with signs of cerebral infarct computed tomography (CT) and intravenous digital subtraction angiography (DSA) were performed. With DSA 63 arterial wall lesions could be seen, in CT 27 infarcts were found. In 9 examinations DSA was not diagnostic. Combination of both methods makes it possible to relate vascular lesions with size and localisation of cerebral infarcts.

Aged↗
PubMed1984

[Nuclear magnetic resonance tomography in space-occupying kidney lesions].

The kidneys in 15 patients (8 renal tumours, 4 cysts and 7 normal patients) were examined by means of super-conductive NMR tomography in order to assess the value of the method and its use in tumour staging. The findings were compared with computed tomography, angiography and surgery. Parenchymal tumours and cysts are easily recognised and differentiated, as they are on CT. NMR demonstrates a pseudo-capsule, which can otherwise only be seen on the angiogram, or on angio-CT. The extent in the peri- and pararenal space, infiltration into neighbouring organs and lymph nodes are equally well seen on NMR and CT. NMR equals angiography for demonstrating invasion into the renal vein and vena cava and, in this respect, is better than CT.

Adult↗
PubMed1984

[Comparison of 133xenon and 123I-isopropylamphetamine for measuring regional cerebral circulation].

In 26 patients the regional cerebral blood flow was measured using 123I-isopropyl-amphetamine. The measurement was performed with a dynamic single photon emission tomograph. In 16 patients we compared the findings with the results of the tomographic 133Xe-Clearance. Both methods seem to be suitable for the measurement of the effective perfusion and gave similar results. In the case of the tomographic 133Xe-clearance we need a more specialized technical equipment whereas the permanent costs are lower and the performance less complicated. Besides the applicability of this method is more universal. On the contrary the use of 123I-isopropyl-amphetamine makes a higher resolution possible depending on the available equipment and does not need an ability to cooperation of the patient. With the presently disposable radionuclides the hope was not yet adequately accomplished, to get a tomographic in-vivo-information of cerebral metabolic and receptor-functions by means of SPECT.

Amphetamines↗
PubMed1984

[Contrast in nuclear magnetic resonance imaging].

It has been shown that signal strength from nuclear resonance and grey scale in NMR depend on pulse sequence, pulse repetition interval, delay time, tissue-dependent parameters, such as relaxation times T1 and T2, proton density, and flow movements. The relative grey scales for tissues using varying pulse sequences can be predicted mathematically. These relationships are shown graphically to indicate to the user the effect of pulse repetition, processing time and T1 and T2.

Adipose Tissue↗
PubMed1984

[Nuclear spin tomographic diagnosis of brain tumors using the contrast medium gadolinium-DTPA].

This study examines the effect of the NMR contrast medium gadolinium-DTPA on image contrast in cerebral tumours. Sixteen patients with space-occupying cerebral lesions were examined on a 0.35 Tesla superconducting scanner, using a T1-weighted spinecho sequence prior to and after the intravenous application of gadolinium-DTPA. In 8 patients T2-weighted spinecho-sequences were obtained before the administration of contrast. The tomograms were evaluated visually and according to quantitative criteria. The use of gadolinium-DTPA helps to evaluate the blood-brain barrier and improves diagnosis by differentiating tumour tissue from edema and from normal brain tissue.

Adult↗
PubMed1984

[Diagnostic significance of intravenous digital subtraction angiography of the supra-aortic extracranial vascular system. Comparative study of i.v. DSA and plain film angiography].

Digital intravenous subtraction angiography (DSA) and conventional film angiography were used to evaluate the diagnostic reliability of DSA-examinations. In 90% of 650 DSA-angiogramms the image quality was diagnostic. For 124 carotid angiographies a comparison of both methods was possible and gave a sensitivity of 87%, a specificity of 96% and an accuracy of 90% for the DSA examinations. The authors believe that digital subtraction angiography is suitable as a screening method for supraaortal vascular occlusive diseases.

Aged↗
PubMed1984

Influence of propranolol, metoprolol, and pindolol on mucociliary clearance in patients with coronary heart disease.

The effects of the beta-adrenoceptor-blocking drugs propranolol, metoprolol, pindolol, and placebo, on mucociliary clearance were studied in three groups of 6 subjects with coronary heart disease and normal lung function. Clearance rates of inhaled 99mTc-labeled human serum albumin minimicrospheres were determined over the apical right region of the lung with a gamma camera. A 3-day medication of propranolol 40 mg b.i.d., when compared with placebo, led to a significant decrease (p less than or equal to 0.05) in mucociliary clearance. Metoprolol 50 mg b.i.d. or pindolol 5 mg b.i.d. did not show any influence on mucociliary clearance. Implications for the use of different types of beta-adrenoceptor-blocking drugs in the treatment of coronary heart disease are discussed.

Adult↗
PubMed1984

[Transvenous digital subtraction angiography for the diagnosis of renal artery stenosis in arterial hypertension. A comparison with conventional angiography].

Venous digital subtraction angiography was performed in 248 patients for the diagnosis of renal arterial stenosis. In 88% of the investigations the digital subtraction angiograms were of diagnostic value. Comparison of digital angiography and conventional angiography was made for 57 renal arteries (25 investigations). In 52 renal arteries we found the same results with both methods, in 5 renal arteries the digital angiography showed false positive results. The spatial resolution of digital subtraction angiography is sufficient for the correct diagnosis of significant renal arterial stenosis. With regard to the lower invasion of digital subtraction angiography compared to conventional angiography the first method should be used for clarification of renal arterial hypertension.

Angiography↗
PubMed1984

[Suspected herniated disk--differential diagnostic case studies by lumbar CT].

The most common reason a patient is referred for spinal CT examination is to exclude a ruptured intervertebral disc. Besides nerve root entrapment due to herniated disc, a number of unusual or unexpected conditions have been encountered in the course of CT lumbar spine studies. These include spondylolisthesis, spinal dysraphism, Paget's disease, and inflammatory, neoplastic, or metastatic lesions. The application of spinal (small-circle) target imaging includes the risk to overlook soft tissue lesions that extend beyond the reconstruction circle. Therefore, complete (large-circle) circumferential abdominal scanning is recommended in case of a suspected extraspinal cause of sciatica.

Adolescent↗
PubMed1984

[Digital subtraction ventriculography in determining global and regional left ventricular parameters compared to left catheterization cardiography].

Since May 1982 we studied more than 150 patients with heart diseases by means of digital angiography, out of them 46 patients with a history of transmural myocardial infarction were selected. Urografin 76, 30 ml, was administered at a flow rate of 18 ml/s by means of a catheter in the superior vena cava during digital subtraction ventriculography. Results were compared with conventional contrast ventriculograms. The correlation coefficient was r = 0.93 (p less than 0.001) for determination of ejection fraction with both methods. The data in individual cases suggest that DSV is more sensitive than conventional contrast ventriculography in determination of severely reduced ejection fractions. The methods are practically identical in qualitative evaluation of disorders of regional wall motion in the anterolateral region, while DSV is more sensitive than conventional ventriculography in evaluating the apical region. Sensitivity was 85.7% when the two methods were compared in evaluation of the inferior region of the left ventricle. Both methods are identical in demonstration of severely deformed ventricles. Digital subtraction ventriculography may replace conventional contrast ventriculography in some of the situations discussed above.

Analog-Digital Conversion↗
PubMed1984

[Value of sonography, computer tomography, hepatobiliary scintigraphy and nuclear magnetic tomography in diseases of the gallbladder and bile ducts].

The effectiveness of ultrasound, computed tomography, hepatobiliary scintigraphy and nuclear magnetic resonance in diseases of the biliary tract is described. Ultrasound should be the first examination in clinical suspicion of cholelithiasis and has a higher accuracy than oral cholecystography. Computed tomography is very expensive and should be carried out in suspected gallbladder carcinoma, cholecystitis with abscess formation, tumour in the porta hepatis and pancreatic head and in sonographically unclear cases. Nuclear magnetic resonance can determine the ability of the gallbladder to concentrate bile. Ultrasound can distinguish with high accuracy between obstructive and inflammatory jaundice. In clinical suspicion of bile duct lesions an infusion cholangiogram must be carried out, if bilirubin is lower than 5 mg%; if bilirubin is higher, an ERC or PTC should be performed. If in biliary obstruction a suspicion of tumour in porta hepatis or head of the pancreas is present, computed tomography should be effected.

Bile Duct Diseases↗
PubMed1984

The automated waterpath scanner (Octoson)--advantages and limitations in diseases of the liver, pancreas and gallbladder.

In a comparative study of 591 examinations the Octoson and a conventional ultrasound scanner were analysed. Examinations with the Octoson showed a sensitivity of 92% and with a conventional ultrasound scanner a sensitivity of 82% in diseases of the liver. With the long focus of the Octoson's large aperture transducers, it is possible to demonstrate both superficial and deep subdiaphragmatic metastases. It is difficult, however, to find the optimal scanning angle with this system, and for this reason examinations undertaken in disorders of the gallbladder and bile ducts require considerably more time. In pancreatic disease (Octoson sensitivity: 77%; conventional ultrasound scanner sensitivity: 65.35%) the favourable air distribution in the stomach and transverse colon is advantageous when the examination is performed with the patient in the prone position.

Bile Duct Diseases↗