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Biomedical subjects

R Felix

Publications and source records attributed to R Felix.

At least 649 records · Page 36Linked to original sources
PubMed1989

[Imaging of intra-cardiac thrombi with indium 111 scintigraphy].

Intracardiac thrombi can be localized and quantified by Indium-111-labelling of thrombocytes with a high sensitivity and specificity. The scintigraphic procedure has a complementary evidence to echocardiography. Scintigraphy shows activity and age of thrombosis, whereas echocardiography seems to be superior in determination of mass and localization. In older thrombi scintigraphy fails because of organisation and endothelialization of the thrombus surface. For the reason of determination of the age of an intraventricular thrombus this method might have an increasing acceptance.

Aged↗
PubMed1989

[The effect of x-ray contrast media on magnetic resonance tomography of the spinal canal].

The effects of x-ray contrast media on signal intensities were studied. Relaxation times of myelographic contrast media were measured. Whereas relaxation times of Amipaque were longer, compared to CSF, the relaxation times of Duroliopaque, Omnipaque und Solutrast were significantly shorter than that of CSF. Therefore, the qualitative and quantitative effects of different contrast media on signal intensities varied. Most notable was the increase of signal intensity on T1-weighted images due to oily contrast media.

Contrast Media↗
PubMed1989

[X-ray diagnostic strategies in liver and pancreatic tumors].

The following publication describes the diagnostic approach in different benign and malignant space-occupying lesions of the liver and pancreas. An essential prerequisite is that all imaging methods are actually available and can be made use of. While taking the cost factor into consideration, flow diagrams are worked out for haemangiomas, focal nodular hyperplasia, hepatocellular carcinoma and liver metastases, as well as for carcinoma of the pancreas and for insulinoma.

Adult↗
PubMed1989

[Gadolinium-DTPA as an oral contrast medium in magnetic resonance tomography].

80 patients with tumorous or inflammatory abdominal diseases were investigated with the paramagnetic MRT contrast medium Gadolinium-DTPA (Gd-DTPA, 1 mM, 15 g/l mannitol, 6-16 ml per kg body weight) at 0.5 Tesla with T1-, proton density and T2-weighted SE- and gradient-echo sequences. 53 patients were investigated also before the contrast medium was given. Gd-DTPA showed hyperintense labelling of the intestinal loops that was detectable with all excitation sequences and was constant over all phases of the passage. In 35 of the 53 patients investigated before and after application of Gd-DTPA lesions were better imaged while diagnostic improvements, especially for smaller lesions, were achieved in 5 of 80 patients. One third of the patients reported slight meteorism and diarrhoea after the mannitol-containing suspension.

Administration, Oral↗
PubMed1989

[3-dimensional reconstructions of the skull, axial and extremity skeleton].

In a prospective study, 150 threedimensional reconstructions of patients with bone diseases were analyzed. It could be seen that 3 D images were relevant for therapeutic considerations in diseases of craniofacial bones, and to a lesser degree for other skeletal regions. In no case was the 3 D reconstruction the only important factor for the therapeutic decision. The study demonstrated that 3 D imaging of the pelvic bones, especially for necroses of the femoral head, is severely limited without the possibility of computer-aided disarticulation.

Bone Diseases↗
PubMed1989

[Lung thallium uptake for non-invasive assessment of increased pulmonary pressure in mitral valve stenosis].

30 patients (24 females, 5 males) with angiographically proven mitral stenosis as well as 10 healthy controls were investigated by wedge catheterism and thallium-201-scintigraphy to calculate the heart-lung quotient (HLQ) of the isotope. All patients with mitral stenosis could be discriminated from controls by a pathological increase of isotope concentration in the lungs. 4 groups could be subdivided: the 1st group consisted of 21% of the patients with normal pulmonary artery pressure of x = 13.06 mm Hg and a normal HLQ less than 1.1. The 2nd group of 39% of the patients showed passive pulmonary hypertension with a PAm of x = 27.57 mm Hg and HLQ between 1.1 and 1.4 A 3rd group showed PAm of 36.76 mm Hg with reactive pulmonary hypertension and a HLQ between 1.4 and 1.6. The last group showed pulmonary hypertension of x = 45 mm Hg PAm and a HLQ of greater than 1.6. Scintigraphy alone allowed classification of the patients, so the value of this method is proven for pre- and postoperative strategy.

Exercise Test↗
PubMed1989

[Abdominal sonographic findings in patients with AIDS].

The ultrasound findings of 58 patients with AIDS and ARC were analysed retrospectively. In 55% an enlarged liver, in 62% an enlarged spleen, partially with focal lesions, and in 21% enlarged abdominal lymph nodes were diagnosed. The typical focal segmental glomerulosclerosis of the kidney was observed in one case, and cholangitis in 2 patients. Abdominal ultrasound is the first diagnostic procedure to be performed in patients with AIDS and ARC when abdominal pathology is suspected. With US-guided thin needle puncture of the lesions, a histological verification of the pathologic findings is possible.

Abdomen↗
PubMed1989

[Diagnostic strategies in liver and pancreatic tumors using imaging procedures--nuclear medicine].

The different biokinetic behaviour of radioactive tracers which can be monitored by nuclear medicine procedures may be helpful in the diagnosis or differential diagnosis of tumours or tumour-like lesions of the liver or pancreas: autologous red blood cells in the detection of haemangiomas; iminodiacetates in delineation of focal nodular hyperplasia, resp. liver adenomas versus other tumours; colloidal albumin in differentiating focal fatty infiltration from diffuse infiltration by metastases; monoclonal antibodies in revealing liver metastases or abscesses, resp. pancreas neoplasms. In general the clinical suspected diagnosis and the result of morphologic imaging modalities determine the use of the appropriate radioactive tracers.

Adenoma↗
PubMed1989

[New radiotherapy approaches in the treatment of malignant choroid melanoma].

Today the best radiotherapeutic procedure for treating small choroidal melanomas involves the application of rhutenium 106, thereby sparing the bulbus, or application of iodine 125 in larger tumors. In extensive tumors, the additional use of local hyperthermia promises further enhancement of brachytherapy with applicators. In the foreseeable future, therapeutic concepts primarily for the palliative treatment of advanced, metastasing melanomas might include the use of antimetabolites or therapy with monoclonal radioactively changed antibodies.

Antibodies, Monoclonal↗
PubMed1989

[Picture quality of a digital urogram using image enhancement radiography].

The use of digital image radiography in urographic diagnostics yields a high percentage of images that are useful in diagnosis, even at the present state of technical development which is rapidly improving. Our own results obtained in a prospective study on 75 patients supply proof of such diagnostically useful pointers. Clear improvements in demonstrating the details when employing a 28 cm image amplifier input format in place of the additionally used 40 cm are seen only with the system of the renal calices. However, we found that the 40 cm image amplifier input format proved satisfactory in respect of assessing renal contours, kidney pelvis and ureters as far as image quality was concerned. Enhance image quality can be expected in future from the use of wedge-shaped diaphragms as well as a selective influencing of the automatic exposure (several measurement chambers, weighting factors) and the transfer of monitor screen contents to hard copy without incurring any losses during transfer.

Adult↗
PubMed1989

[Postoperative computed tomography control of allogeneic vascular prostheses].

33 CT-studies of 26 patients with alloplastic vascular prostheses were evaluated and compared with postoperative digital subtraction-angiography in 16 cases. 13 patients had no pathologic findings confirmed by further clinical development. In 4 cases bypass infection was diagnosed, which CT findings were perigraft gas (2/4), perigraft fluid (4/4), cm-enhancement (4/4) and fistulas (2/4). 10-21 d. post.-op. sterile hematomas were found in 3 patients. Further 3 cases had 5 weeks-2 post.-op. perigraft seromas. CT was method of first choice for diagnostic of perivascular alterations after bypass surgery. DSA was complementary to CT and should be performed to detect vascular complications.

Aged↗
PubMed1989

[A new multislice gradient echo sequence for magnetic resonance tomography of the liver].

A multislice gradient echo sequence was developed for screening the liver and examined in studies on probands. This sequence is characterized by pronounced T1-weighting and low susceptibility to artifacts as well as a good contrast-to-noise ratio. Examination of the probands yielded suitable parameters for the repetition time, the delay echo, the excitation pulse angle and the number of data acquisitions. The optimized sequence yields, at a repetition time of 306 msec and an echo delay of 12 msec, 18 adjacent slices. With these measurement parameters an excitation pulse angle of 90 degrees was found to be adequate. Four data acquisitions (5.4 minutes measurement time) resulted in an effective reduction of motion artifacts. Compared with the T1-weighted spin echo sequences, the entire liver can be measured in half the time when using the multislice gradient echo sequence.

Humans↗
PubMed1989

[MRI of bronchogenic carcinoma].

47 patients with histologic/cytologic confirmed bronchogenic carcinoma were examined with CT and MRI. Negative and contrast enhanced CT examinations were performed, MR images were obtained with ECG gated T1- and T2-weighted SE sequences in axial and coronal planes. Both methods were evaluated with respect to tumor imaging and delineating of tumor extensions. CT and MRI were generally in agreement for primary tumor and lymph node staging. 7 out of 10 patients with malignant pericardial involvement and 3 out of 27 patients with mediastinal subcarinal lymph node metastases were identified only in MR images. MRI was superior to CT in demonstration of aortic involvement, poststenotic syndrome and extension of chest wall invasion. Additionally MRI gave functional informations about blood flow in case of superior vena cava obstruction.

Aged↗
PubMed1988

Production of hemopoietic growth factors by bone tissue and bone cells in culture.

This study was carried out to determine whether bone might be a source of hemopoietic growth factors. Both neonatal murine calvaria and primary cultures of cells isolated from calvaria released, upon stimulation with lipopolysaccharide, an activity that stimulated the growth of the interleukin (IL) 3-dependent cell lines, 32D cl, 123, and NSF 60. Upon gel filtration, this activity eluted with a molecular weight of 30,000 kDa. Further characterization, however, revealed that the major activity in conditioned medium was not IL 3. Activity was absorbed by DEAE-Sephacel at low salt concentration, whereas IL 3 does not adhere. Furthermore, an IL 3-specific antiserum did not neutralize the activity from cells and only partly neutralized the activity generated by whole calvaria. After gel filtration, the 30-kDa activity stimulated the growth of very large colonies in semisolid medium consisting mainly of granulocytes with the remainder being macrophages. No colony types belonging to other hemopoietic lineages were found, indicating, again, that the activity was not identical to IL 3. Subsequently, conditioned medium was fractionated by hydrophobic chromatography on Phenyl-Sepharose CL-4B, yielding two peaks of activity. Neutralization of activity with antisera to granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL 3 and use of colony assays showed that medium conditioned by whole calvaria contained GM-CSF and granulocyte CSF (G-CSF) in similar amounts together with a little IL 3, and medium conditioned with calvaria cells contained GM-CSF and little G-CSF. We conclude that bone releases hemopoietic growth factors that could contribute both to hemopoiesis and to the recruitment of osteoclasts from progenitors resident in the adjacent marrow.

Animals↗
PubMed1988

The value of paramagnetic contrast agent gadolinium-DTPA in the diagnosis of pituitary adenomas.

The purpose of this study was to assess the role of MR imaging and the paramagnetic contrast agent Gadolinium-DTPA(Gd-DTPA) in the diagnosis of pituitary macroadenomas. 44 macroadenomas were examined with MRI before and after intravenous application of Gd-DTPA. Gd-DTPA produced excellent enhancement of solid adenoma. The best contrast between adenoma and surrounding structures could be gained on post-Gd T1-weighted images. Post-Gd images were equivalent to pre-Gd images in the evaluation of supra- and infrasellar extensions of macroadenomas. Post-Gd images had advantages in the evaluation of cavernous sinus invasion by adenoma. The difference in degree of contrast enhancement between adenoma and cavernous sinus facilitated the exact evaluation of lateral extension by adenoma in 18 cases. Almost equal degree of enhancement of both structures impaired tumor-sinus contrast in 2 cases. In the other 24 cases the tumor filled the cavernous sinus completely. It is our opinion that Gd-DTPA can be used on a widespread basis because of its excellent capability to highlight and delineate pituitary adenomas.

Adenoma↗