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Biomedical subjects

E Bücheler

Publications and source records attributed to E Bücheler.

At least 55 records · Page 3Linked to original sources
PubMed1990

[The importance of thoracic CT in the diagnosis of pulmonary sarcoidosis].

The CT findings in the lungs of 52 patients with histologically confirmed sarcoidosis are described. In addition to a nodular pattern, reticulo-nodular, reticular, diffuse infiltrative and streaky shadowing due to fibrosis could be recognised. Pleural lesions, bronchial ectasis and mediastinal and hilar lymph node changes could be diagnosed. The high sensitivity of CT contrasted with its relatively low specificity. At present CT is useful for analysing the pulmonary pattern when planning lung biopsy or lavage. In some cases, the diagnosis of pulmonary sarcoidosis can be made by CT, but the exact criteria for diagnosis and differential diagnosis must be borne in mind.

Adult↗
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

[Supercilium acetabuli. A stress indicator of the hip joint cartilage].

A thousand radiographs of the hip joints in adults were evaluated quantitatively and the following statistical conclusions were drawn: the normal forms of the supercilium acetabuli are either parallel or convex. Wedge-shaped supercilia indicate increased stress on the cartilage only in cases with hip dysplasia. A supercilium of more than 4mm raises the suspicion of increased stress on the cartilage. Normally, the joint space as shown on a radiograph does not fall short of 3mm. Eight formulas have been defined which can be used after planimetry of the supercilium and the articular surface in order to indicate increased stress on the cartilage and a risk of developing an arthrosis of the hip. These formulae are of practical value if the radiographs appear normal to visual inspection.

Acetabulum↗
PubMed1989

[MRT of extracranial hematomas at 1.5 T using spin echo and gradient echo sequences].

Magnetic resonance imaging (MRI) at 1.5 T was performed in 25 extracranial haematomas using spin-echo (SE) and fast-field-echo (FFE) sequences. The age of the haematomas was in 11 cases less than 2 days and in 9 cases more than 14 days. Fresh haematomas were isointense to skeletal muscle on T1-weighted SE images. With T2-weighted SE sequences, fresh haematomas had high signal intensity on the first day, but became inhomogeneous with predominantly low signal intensity on the following days. Areas of low signal intensity could be demonstrated by T2-weighted FFE sequences already on the first day after bleeding. Subacute haematomas were recognised by their high signal intensity on the T1-weighted SE images. Also with T2-weighted SE and FFE sequences, subacute haematomas showed increasingly high signal intensity. The characteristic appearance of haematomas facilitates their identification with MRI.

Hemarthrosis↗
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

[Poststenotic flow in MRT: phantom measurements using spin-echo and gradient-echo sequences].

A flow model was used to study the appearance of poststenotic flow on spin-echo (SE) and fast-field-echo (FFE) images. On SE-images, extensive signal void distal to the stenosis was observed even with low flow velocities. FFE-sequences with short echo time and flow-compensated gradients demonstrated poststenotic loss of signal intensity only with high flow velocities. On FFE-images, the poststenotic signal loss increased with the severity of the stenosis, if total flow across the stenosis was maintained. The lower limit of the mean flow velocity within the stenosis, for which signal void was observed, appeared essentially independent of the degree of the stenosis. The results demonstrate the capability of flow-compensated FFE-sequences to assess poststenotic turbulent flow.

Arterial Occlusive Diseases↗
PubMed1988

[High-resolution MRT with increased magnetic field gradients and a 512(2)-data matrix: initial clinical experiences].

By increasing the strength of the magnetic field gradients of a whole-body imager to 9.4mT/m, it was possible to obtain spin-echo images with short echo delays and high spatial resolution. The reduction of the pixel size was effected either by decreasing the field of view or by increasing the scan matrix (512(2) pixel). To prevent loss of signal-to-noise ratio, the scan parameters had to be carefully selected. With the 512(2) matrix, the resolution could be increased without decreasing the field of view, so that backfolding artifacts were avoided. In comparison with the 256(2) matrix, the 256 x 512 matrix provided improved resolution in the frequency encoded direction without an increase in acquisition time.

Humans↗
PubMed1988

[Cine-MRT for studying regional myocardial function].

Cine-MRT was performed in 8 healthy subjects and in 16 patients with myocardial infarction, in whom regional wall motion abnormalities had been demonstrated by left ventricular angiography. Short axis and long axis slices were obtained by angulation of the imaging planes according to the orientation of the cardiac axes. From the end-diastolic and end-systolic images, systolic wall thickening and radial wall motion were determined. In healthy subjects, regional variation in wall thickening was not significant. Patients with myocardial infarction demonstrated abnormal wall motion within the infarct region. Discrepancies between wall thickening and wall motion were observed in 8 patients.

Adult↗
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↗
PubMed1987

[Functional imaging of blood flow velocity amd myocardial perfusion using the Fourier transform parameter].

In the past, the radiology of the cardiovascular system has consisted of angiographic investigations which only demonstrate morphology. The introduction of digital techniques into radiology has made possible the demonstration of pure morphology and beyond that, calculations which provide functional information. We demonstrate functional images which, by using Fourier transformations, provide information on blood flow and organ perfusion. In this way, it is possible to obtain important additional diagnostic information concerning the cardiovascular system, without imposing any further stress on the patient.

Blood Flow Velocity↗
PubMed1987

[Pulse triggering in magnetic resonance tomography in high-field strength].

Gated images of patients with stronger pulsation artefacts in the brain stem were produced on a 1.5 tesla MR-imager, registering blood pulsations by means of a finger plethysmograph. A minimization of movement artefacts was achieved and thus sufficient diagnostic-value of images in these patients was noticeable. This gating method seems to be a promising simple alternative compared to the well known cardiac gating for imaging of the head and neck area. Its advantages and limitations are demonstrated.

Brain Stem↗
PubMed1987

[Risks and artifacts in MRT (1.5 tesla) caused by metallic foreign bodies. Studies on phantoms and 60 patients].

Our experience of the effects of metallic foreign bodies on MRT high field examinations is described. In vitro measurements showed moderate magnetic torsion or displacement in a few cases. The findings in 60 patients with various metal foreign bodies and the resulting artifacts are discussed. Despite local loss of information, in the majority of cases there is additional evidence provided by MRT, which suffers less from foreign body artifacts than does CT. Stainless steel implants result in some signal loss and geometric distortion, but do not usually constitute a danger to the patient and do not affect the diagnostic information from surrounding structures.

Foreign Bodies↗
PubMed1987

[Methodologic variants on rapid MR imaging of the liver].

The development of rapid imaging methods makes it possible to obtain T1 and T2-weighted MR images in less than 15 seconds. Consequently images can be obtained without respiratory artefacts. An attempt has been made to obtain optimal factors for the fast-field-echo procedure in order to obtain satisfactory images of the liver with T1 and T2 sequences. By moving the examination couch, it is possible to obtain 10 mm transverse sections without gaps throughout the entire liver in a reasonable time. The additional use of contrast medium (Gd-DTPA) provides information about perfusion and leads to an increase in contrast between lesions and normal liver tissue with adequate image quality. The method is particularly valuable before surgery for liver metastases.

Contrast Media↗
PubMed1986

[Imaging of ventricular wall motion using venous DSA. A new method in radiologic cardiac diagnosis].

Until now, angiographical and nuclear medicine examination techniques for imaging left ventricular wall motion have been presenting with difficulties endemic to the methods themselves. For the first time in cardiological diagnostics, digital subtraction angiography (DSA) makes it possible to perform a fairly non-invasive examination with good spatial and temporal resolution. Functional analytic evaluation, however, still demands time-consuming, complicated post-processing. In this article we introduce a method that uses an additive window technique for the immediate generation of wall motion images.

Angiography↗
PubMed1985

[Applicability of digital methods in x-ray diagnosis].

The significance of digital examination methods continues to grow. Since the introduction of computer tomography, two additional digital imaging modalities-digital subtraction angiography (DSA) and magnetic resonance imaging (MRI)--have been developed. In this paper we present basic techniques of computerized image processing and outline foreseeable future developments. Furthermore, we discuss the possibilities and problems presented by digital picture archiving and communication systems (PACS).

Analog-Digital Conversion↗