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Biomedical subjects

G Witte

Publications and source records attributed to G Witte.

At least 19 recordsLinked to original sources
PubMed1992

[Superselective interventional angiography].

The authors report on the clinical application of superselective interventional angiography within the framework of revascularisation and occlusion. A coaxial catheter system is used for probing, consisting of an F 5 angiography catheter as guiding catheter and an F 3 catheter as internal catheter. The internal catheter is equipped with a shaft with segments of different flexibility and can take up a guide wire of 0.018" that is sufficiently stable to be rotated and guided. The interplay between the guide wire, which can be manipulated, and the flexible internal catheter enables superselective probing even of peripheral vascular areas. As may be required by the basic disease, the necessary interventional measures can be taken via the superselectively placed microcatheter. Superselective interventional angiography is indicated as an occlusive measure in preoperative vascular occlusion followed by palliative tumour resection, embolisation in haemangioma, chemoembolization in tumours of the liver. Superselective angiography is used for revascularisation in the local lysis of peripheral vessels. Due to the on-target superselective approach, side effects are markedly less than those observed with the interventions performed to date.

Angiography↗
PubMed1992

[Results of CT-controlled puncture of the thorax].

Results of 56 CT-guided biopsies in 45 patients are presented. Aspiration biopsies (n = 23) had a usable result in 75% of the cases; cutting biopsies (n = 33) in 80%. The main complication was the pneumothorax with 9%; in one patient the procedure caused a haemoptoe.

Humans↗
PubMed1992

[Results of CT-guided puncture biopsies in the abdominal and pelvic regions].

Results of 285 abdominal and pelvic CT-monitored biopsies are presented. 81.6% of the histological biopsies (n = 46) were evaluable (39.1% right positive, 43.5% right negative, 4.35% suspect). In 13% no definite findings were made. For the cytologic examinations and those due to an abscess 44.8% led to a right positive diagnosis and 23.8% gave a true negative finding. In 4.2% of the cases a suspect finding was given. 28% of all cytological evaluations were not definite. The complication rate was 1%.

Adolescent↗
PubMed1991

[Chemoembolization in primary hepatocellular carcinoma].

The only generally recognised form of treatment for primary liver cell carcinomas is partial liver resection; occasionally this may be curative. This form of treatment is only applicable in 5% to 30% of patients. All drug-based forms of treatment have proved of little value. The new interventional radiological method of chemo-embolisation has shown results in improving survival rates which are comparable with resection. By using a new coaxial catheter system, embolisation can be performed as a selective intrahepatic procedure; it has few side effects and the quality of life subsequently does not deteriorate.

Carcinoma, Hepatocellular↗
PubMed1991

Intestinal absorption of aluminium: studies in the isolated perfused rat intestinal preparation.

Aluminium (Al) absorption was studied using an isolated in vitro vascularly perfused rat intestinal preparation. Al was introduced into the lumen as AlCl3, Al(NO3)3 or Al lactate to give final concentrations equivalent to 0.625, 1.25, 2.50, 5.00, or 10.00 g/L of Al. The intestinal tissue remained viable up to 5.0 g/L of Al. The amount of Al associated with intestinal tissue after 90 min increased with the concentration up to 5 g/L of Al for chloride and nitrate and 10 g/L of Al for lactate. The time course of Al disappearance from the lumen followed a single exponential decay when the intestinal lumen was perfused with 0.625 g/L of Al as the chloride salt. The total amount of Al appearing in the vascular perfusate after 90 min was always small. Absorption quotes ranged between 0.005-3.2% depending on the salt and concentration used. Addition of transferrin to the VM caused a 2-fold increase in the amount of Al appearing in the vascular effluent in comparison with controls when 1.25 g/L of Al as AlCl3 was introduced into the lumen. Al tissue content was not affected.

Aluminum↗
PubMed1990

[A comparison of digital luminescence radiography and the conventional film-screen technic in pulmonary coin lesions--a clinical study].

The aim of this investigation is the evaluation of DLR for the radiological diagnosis of intrapulmonary coin lesions. For this, a DLR system was used which had been specially developed for chest radiography. Early results were unsatisfactory and therefore specific image parameters were developed. The scope for dose reduction was also investigated. Oncology patients were examined by DLR and by our reference system. Results show that DLR is better than conventional images if edge enhancement is carried out, using the specific parameters. The superiority of the optimised digital images is apparent particularly in those portions of the lung that are obscured by the cardiac or diaphragmatic shadows. Because of image noise, a dose reduction of only 28% is possible, compared with our reference system.

Evaluation Studies as Topic↗
PubMed1990

[Clinical and technical experiences with digital luminescent radiography in phlebography of the leg].

Digital luminescence radiography is being increasingly integrated into clinical routine work and is fundamentally suited to replace x-ray film/screen takes. After the necessary optimization of the specific image processing procedure we examined the diagnostic efficacy of this method in respect of phlebography of the leg. If the radiation dose was reduced by 47% in relation to the reference system, the usefulness of the findings in arriving at the diagnosis was by no means reduced under the conditions of high contrast that apply in phlebography, but there was also no additional advantage in respect of diagnostic accuracy. The technical advantages concern mainly the absence of wrong exposures, the possibility of subsequent processing of the image to improve the image quality, and digital storage.

Evaluation Studies as Topic↗
PubMed1990

[The lateral thoracic radiograph in the intensive care unit using digital luminescence radiography].

The digital luminescence radiography (DLR) technique is being used increasingly for clinical diagnosis, particularly in intensive care . Since the installation of a DLR unit, we have carried out more than 20,000 examinations of the chest on patients in intensive care. 12.1% of these were lateral radiographs. In this way, the diagnosis can be made of the extent of a pleural effusion, the presence of a ventral pneumothorax or of atelectasis. Using DLR, these examinations can be carried out at the bedside and have improved the radiological investigation of patients in intensive care.

Humans↗
PubMed1990

[Partial resection of primary liver cell cancer].

Between 1985 and 1990, 47 patients with primary hepatocellular carcinoma (HCC) underwent surgery (n = 27), chemoembolization (n = 12) or palliative resection followed by chemoembolization (n = 5). In 85% of the patients a T3/T4 tumor stage was found, 68% had liver cirrhosis and 42% were older than 70. Mortality was 18.7% after liver resection and 0% after chemoembolization or combined treatment. Average survival was 4.4 months after chemoembolization, 11.6 months after resection and 11.6 months after palliative resection of the HCC followed by chemoembolization with angiostat/adriblastin.

Aged↗
PubMed1989

[Digital luminescence radiography. A new method of study in thoracic diagnosis at the intensive care unit].

The digital luminescence-radiography (DLR) technique relies on a complete digitalization of the X-ray image. Luminescence crystals on the imaging plate serve as an energy reservoir following their exposure to ionized radiation from any conventional X-ray source. A Helium-Neon laser stimulates the electrons in their high energy bands and therefore will be dropped back emitting luminescence. This luminescence is digitized by the DLR-System thus delivering a complete digital image to the image processor for subsequent processing and evaluation. The processed digital image is then recorded on a conventional film or a monitor screen. More than 3000 chest examinations using DLR have been performed on intensive care unit (ICU) patients at the University Hospital Eppendorf following the first eleven months since the clinical introduction of this new technique. The positive aspects of DLR such as high-contrast resolution and optimal reproducibility were clinically evaluated under ICU conditions. It was shown that DLR greatly improves the quality of the chest X-rays of all ICU patients and offers the following advantages: reproducibility, lateral chest projection, no insufficient exposure, reduction of exposure dose, electronical post-processing and storage, quality preserving digital storage and copying.

Humans↗
PubMed1989

[Thoracic diagnosis at the intensive care unit: digital radiography].

Only few reports have been published so far on the clinical use of digital luminescence radiography (DLR). We report on 3.000 x-ray examinations of the thorax in the intensive-care ward performed by us since a suitable system (Philips PCR) had been installed in December 1987. The following advantages must be pointed out in respect of using DLR in thoracic diagnosis in the intensive-care ward: No faulty exposures; the thorax can be x-rayed with the patient recumbent in bed, with lateral take: the image brightness in maintained at a constant level by histogram selection; electronic image processing and storage. Hence, DLR entails considerable improvement in x-ray diagnosis of intensive-care patients.

Humans↗
PubMed1988

[NMR tomography of thoracic aortic dissection].

The results of magnetic resonance imaging in 10 patients with dissection of the thoracic aorta are presented. In 8 patients, the intimal flap was clearly contrasted from flowing blood in both lumina. In 2 patients the lack of phase shift of the intraluminal signal indicated complete thrombosis of the false lumen. Oblique sagittal sections parallel to the aortic arch and coronal sections through the ascending aorta demonstrated the extent of the dissection and provided information about the involvement of the origins of the coronary arteries and the branch vessels of the aortic arch. In 7 patients, the proximal site of communication between both lumina could be localized.

Aortic Dissection↗
PubMed1988

[The chest picture in the intensive care station as visualized by digital luminescence radiography].

To date there have been occasional reports on the technical aspects and accounts of the clinical use of digital radiography. There has, however, been a lack of reports on the clinical use of the technique in a large number of patients. We report our experience concerning more than 1250 chest x-rays on patients in intensive care; these have been carried out since December 1987, using a digital system. The method produces improvement in the radiological diagnosis of patients in intensive care; this is due to avoidance of incorrect exposures, the ability to obtain lateral films, consistent exposures and the ability to manipulate and store images electronically.

Humans↗
PubMed1988

[Magnetic resonance tomography of a thoracic aortic aneurysm].

The results of magnetic resonance imaging in 16 patients with non-dissecting aneurysm of the thoracic aorta are presented. Scans with ECG-gated spin-echo sequences in transversal, coronal, and left anterior oblique views demonstrated the size and extent of the aneurysms. Measurements of the maximum aneurysmal diameter differed by less than 5 mm from measurements obtained with computed tomography. In 6 of 7 patients with presence of wall adherent intraluminal signal, phase images were able to differentiate accurately between mural thrombus and slow blood flow.

Adult↗
PubMed1988

Effectiveness of intraarterial plasminogen application in combination with percutaneous transluminal angioplasty (PTA) or catheter assisted lysis (CL) in patients with chronic peripheral occlusive disease of the lower limbs (POL).

The accepted correct procedure for treating occlusive arterial diseases includes surgical disobstruction, CL as well as PTA. Combined non-surgical strategies are effective in about 60% of these patients. However, a high risk of rethrombosis despite from the prophylaxis with anticoagulants like heparin or antiplatelet drugs like ASA is proven, especially in patients with multi-segmental stenosis as well as in patients with extensive narrowing of the arteries. In these cases primary lesions (endangitis obliterans) or secondary lesions of the endothelium cause local depletion of plasminogen in the endothelium. Independent of the method used for reopening the vessel in these patients, a significant progression of the vessel disease and a high rethrombosis rate during longterm follow-up is observed. These results lead us to apply plasminogen locally to decrease the rate of rethrombosis. In patients suffering from stage III-IV (La Fontaine) including patients with multi-segmental stenosis as well as extended narrowing of the artery, PTA in combination with CL was performed. The catheter was placed as near as possible to the thrombus. In some cases the 'fibrinolyticum' could be injected directly into the thrombus. In these cases a bolus of 4,000 U/ml was locally infused, otherwise 1.0-1.5 million U urokinase per 24 hrs. were locally infused with heparin. In 28% (22 patients) no sufficient clinical response occurred using this combined therapy and plasminogen was applied locally. The following criteria supported our decision to include the patients in this study: 1. Insufficient response occurring after 12-24 hrs. of local infusion. 2. Following 6 bolus injections no reopening of the vessel occured within 60 minutes or the clinical response was insufficient due to rethrombosis. 3. Insufficient effects of lysis therapy after 2 hours and contraindication for a systemic fibrinolytic therapy (e.g. hypertension, age, etc.). 1,000 U plasminogen per ml were infused locally or 2,000 U up to 5,000 U plasminogen (in 5 to 10 ml 0.9% saline) were infused slowly (2-4 minutes infusion time) into the catheter in these patients 10 minutes after unsuccessful treatment with local urokinase therapy. Five minutes after administering plasminogen local intraarterial fibrinolytic therapy with urokinase was continued. No severe side effects due to this therapy were observed, although some patients suffered from acute pains in the peripheral segments of the arteries occurring immediately after infusion of plasminogen. In 16 of 22 patients a complete recanalization occurred and in 3 patients a satisfying clinical improvement was observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗