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Biomedical subjects

S Meindl

Publications and source records attributed to S Meindl.

11 recordsLinked to original sources
PubMed1989

[Intracranial hemorrhage in MRT].

About 10% of all intracranial findings in cranial MRI were hemorrhages, or findings associated with bleeding. There was great variation in the hemorrhages as a result of their location and their age, and this could disguise the underlying lesions. Therefore a knowledge of the typical appearance of spontaneous bleeding and tumor bleeding is necessary for interpretation of the MRI findings. During its course, cerebral bleeding shows all of the known interactions between biochemical and histological factors and MRI signal. Thus, an understanding of the variations during the clinical course of bleeding is helpful for a better understanding of contrast mechanisms in MRI.

Cerebral Hemorrhage↗
PubMed1988

[Gadolinium dimeglumine gadopentetate compared to CPMG sequencing and image synthesis].

The skulls of 46 patients were examined by means of ordinary scans and after contrast. 24 of these patients with cerebral abnormalities had scans, using identical planes, with and without contrast and with CPMG sequences. Contrast in intracranial, but extracerebral (extra-axial), tumours (meningiomas, neurinomas) was much better after using contrast, but intracerebral (intra-axial) tumours were mostly shown as well on T2-rated CPMG sequences. Image synthesis has shown that contrast uptake occurred only in solid tumour regions.

Brain Diseases↗
PubMed1987

[Initial clinical results of tissue characterization by T1, T2 and proton density in nuclear magnetic resonance tomography].

The NMR parameters (proton density, relaxation times T1 and T2) have been assessed by Carr-Purcell-Meiboom-Gill (CPMG) spin echo sequences. A computer assisted analysis of the data of 21 patients with cerebral tumours allowed a classification of tumour tissue in different tumours. The use of quantitative procedures for tissue characterisation allows the differentiation of benign and malignant brain tissue by characteristic colour coding demonstrating morphological details like tumour, edema and necrosis as well as indicating the histological types of the tumours of the central nervous system.

Brain↗
PubMed1987

[Reference substance for initialling the marker space in NMR tomography].

Dimethylsiloxane polymers are tested to serve as a reference medium in quantitative MR imaging. Simultaneously measured during the patient's examination, the reference data are used to normalize the intrinsic MR tissue parameters. This method helps to achieve interindividual comparability of tissue vectors which are defined by proton density, spin-spin and spin-lattice relaxation times, thus leading to a remarkable improvement in tissue classification.

Brain↗
PubMed1986

[Possibilities in using a specific pulse sequence (interlocking sequence) to improve the specificity in NMR tomography].

Methods and possibilities of application of a doubled and interlaced pulse sequence ("interlaced sequence") are discussed. This makes it possible to perform contrast variations and pulse sequence variations subsequently, as well as to determine the parameters proton density, T1 and T2. The selectivity of the combination of all three parameters for tissue classification is demonstrated by means of an individual case and seems to promise a higher specificity of MR tomography.

Brain Neoplasms↗
PubMed1986

[The pattern of regional disorders of wall motion in primary dilated cardiomyopathy].

Regional left ventricular wall motion was measured in 41 patients with dilated cardiomyopathy (DCM) and 30 healthy normal controls. Global and regional left ventricular function was noninvasively determined by radionuclide angiography (RNA). The amplitudes and phases of the first Fourier coefficient of the regional time-activity curves were used to measure regional wall motion. The normal left ventricle has its strongest contractions in the apical and distal antero-septal regions. In contrast, the left ventricle of patients with DCM contracts the least in these segments. These regional wall motion impairments are parallel to the reduced global left ventricular function. Since such a typical pattern of reduced wall motion can already be demonstrated in patients with mild DCM, determination of regional left ventricular wall motion can help to improve the early detection of DCM.

Cardiac Output↗
PubMed1985

Brain tumors: detection and typing by use of CPMG sequences and in vivo T2 measurements.

A spin-echo sequence with 24 echoes (Carr-Purcell-Meiboom-Gill sequence) was evaluated to determine the usefulness of magnetic resonance (MR) in detecting and typing brain tumors. The TEs in these examinations were between 28 and 346 msec, and the TR was 860, 1260, or 1660 msec. The results of the MR examination of 32 histopathologically proved tumors are presented. All but one tumor could be detected by MR. Tumors generally were obvious on MR due to the higher contrast enhancement of these lesions, especially with a TE longer than 100 msec. T2 values calculated from an eight-point fit, however, did not allow discrimination of different tumors, nor did they allow differentiation between tumor, inflammatory tissue, and demyelination.

Adolescent↗
PubMed1985

[T2-analysis of normal and pathological structures of the head].

Analyses of T2 values (spin-spin relaxation time constant) in magnetic resonance tomography were carried out in 29 patients with brain tumours. 21 of these had tumours of the glioma group (17 astrocytomas WHO I-III and oligoastrocytomas, 4 glioblastomas). Measurements were effected both pixel by pixel and according to relevant ROI (regions of interest). Although the measurements yielded a T2 value which was typical of the disease, it was individually difficult to effect proper grading on account of the scatter occurring from case to case. Markedly more relevant information was obtained by the introduction of profile measurements in T2 images. The relation between T2 profile and histology of the gliomas permits rough grading between more or less differentiated gliomas.

Adolescent↗
PubMedDate not supplied

Information processing in nuclear magnetic resonance imaging.

An extended image analysis and classification system is presented to discuss the principal composition of the components as well as the methods of its realization in the field of reference based NMR diagnostics and tissue characterization.

Brain↗