[Localized 31 phosphorus NMR spectroscopy of the human heart--development of a measuring method and initial clinical application]. / Lokalisierte 31Phosphor-NMR-Spektroskopie des menschlichen Herzens--Entwicklung einer Messmethode und erste klinische Applikation.

In this work, the technique of 31P-NMR-spectroscopy is applied for the first time to diagnose coronary heart disease in patients, using a suitable measuring technique. In 13 healthy volunteers we applied a method comfortable and tolerable for patients, which enabled us to examine the myocardium inside the reception area of a surface coil. Concerning myocardium-specific selectivity and sensitivity the localization techniques FROGS (Fast-ROtating-Gradient-Spectroscopy), 1-D-ISIS (1-Dimensional-Image-Selected-In-vivo-Spectroscopy) and 3-D-ISIS were compared. By a combination of the 3-D-ISIS-technique with magnetic resonance imaging, we obtained a monitored position of the volume of interest (VOI) within the myocardium, thus gaining a selective measurement. The cube-shaped VOI with a lateral length of 50 mm was placed into the apical-septal area of the myocardium. On the basis of the obtained results, we examined seven patients suffering from coronary heart disease, which was symptomatic and verified by coronary angiography. The 31P-NMR-spectra of the two examined groups were computed into numbers representing the relative content of the myocardial high-energy-phosphates. In addition, the quotients PCr/ATP and Pi/ATP were calculated and compared. With this small number of cases the evaluation of the PCr/ATP-ratios already showed a significant difference of 0.34 (p less than 0.01) between patients with coronary heart disease (0.49 +/- 0.19) and healthy volunteers (0.83 +/- 0.27). The findings suggest the conclusion that 31P-NMR-spectroscopy is able to be instrumental in the diagnostic detection assessment of the metabolic state in coronary heart disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantification of pulsatile flow in MRI by an analysis of T2 changes in ECG-gated multiecho experiments.

The transport of magnetization by fluid flow through thin slices in MRI causes changes in the measured T2 relaxation time. This effect is used to compute velocity values at several different times relative to the cardiac cycle using data in ECG-gated multiecho experiments which last a few minutes.

Description of flow phenomena in magnetic resonance imaging.

The magnetic resonance (MR) signal from the hydrogen nuclei of blood is not only determined by the MR parameters T1, T2 and proton density, but is strongly dependent on the movement of the protons. Magnetic resonance imaging (MRI) offers therefore the possibility to visualize the distribution of moving spins, especially blood flow, noninvasively and without contrast agents; moreover, the velocity of the moving spins can be quantified. Flow phenomena in MRI are a pretentious field because the complicated hydrodynamics of the living system is coded in the MR signal; therefore, an understanding of the underlying physical principle of the MR signal is required to interpret and extract flow information from the image. However, rather simple theoretical and experimental models of fluid transport in vessels allow to explain the main features of various effects observed in images.

Analysis of the wall permeability of blood vessels in the rat mesentery.

The transport of fluorescent tracer molecules of various molecular weights (MW 340-300,000) within the blood vessels and through the vessel walls into the perivascular tissue of the rat mesentery was studied microscopically. Using a highly sensitive TV-tube the fluorescence intensities were transformed into video signals and recorded for subsequent analysis. The results show that small molecules, such as the water-soluble dye fluorescein-sodium ( F1Na ) (MW 340) can pass through the wall of all blood vessels with minimal delay, whereas the passage of large molecules, such as the serum proteins (MW greater than 60,000), depends very strongly on the diameter of the vessels and on the medium in which the mesentery is embedded during the observation. In this respect, no difference was registered between vessels of the arterial and of the venous part of the microcirculation. The large serum protein molecules moved through the blood vessel walls at specific leakage points. The small dye molecules, however, traversed the wall uniformly along the entire length of the blood vessel. The small-molecule behavior could be described by a passive diffusion model with a cylindrical diffusion source.

Influence of staining on fast automated cell segmentation, feature extraction and cell image analysis.

FAZYTAN, a system for fast automated cell segmentation, cell image analysis and extraction of nuclear features, was used to analyze cervical cell images variously stained by the conventional Papanicolaou stain, the new Papanicolaou stain and hematoxylin and thionin only; the last two dyes are used as the nuclear stains in the two versions of the Papanicolaou stain. Other dyes were also tried in cell classification experiments. All cell images in the variously stained samples could be described by the same nuclear features as had been adapted for the discrimination of conventional-Papanicolaou-stained cells. Variances were lower for thionin-stained cells as compared with hematoxylin-stained cells. By application of spectrophotometry, it was confirmed that the spectra of the cytoplasmic counterstains are superimposed on those of the nuclear stains. It appears that a variety of dyes are suitable as cytologic stains for cell classification by the FAZYTAN system, provided that they achieve sufficiently strong nuclear-cytoplasmic contrast by precisely delineating the chromatin texture.

[Early cancer diagnosis through automated cytoanalysis (Fazytan system)]. / Krebsfrüherkennung durch automatische Zyto-Analyse (Fazytan-System).

A prescreening system for the early detection of uterine cancer was developed. For the diagnosis of each input specimen (PAP-stained), a figure of malignancy has to be calculated automatically. Methods, problems and results of the system are summarized in this paper. Some thousand microscopic subfields of a specimen are successively scanned by an optimized TV-camera with high spatial resolution. The automated specimen analysis can be described by a two step procedure: single cell classification and evaluation of cell population. For the single cell classifier only features derived from the nucleus are used. The pattern recognition procedures are based on a processor-oriented strategy, and can be adapted to other cytological specimen. The algorithms have been tested with 3 . 10(5) cell images of about 300 specimens.

[Methodological and technological requirements in cell image analysis]. / Methodische und technologische Anforderungen an Zellbildanalysatoren.

Methodological and technological requirements for cell image analysing systems are discussed with respect to the following applications: automated prescreening systems for the early detection of tumors; cell analysis systems for diagnostic assistance; early detection of benign or malignant changes in the field of "environmental pathology". The solution of these problems requires sophisticated image processing systems (high spatial resolution) which take use of supervised learning algorithms based on representative data banks. The wide spread applications in the field of automated and analytical cytology need processing systems which have the capability of systematical parameter adaptation to different analysis problems.

Dispersive concentrating systems based on transmission phase holograms for solar applications.

The efficiency of photovoltaic generators based on different semiconductor materials with optimized band gaps can achieve considerably higher values than those contained with single-junction solar cells. A new type of concentrating system is presented which allows high concentration and simultaneous splitting of the spectral region. This dispersive and concentrating (DISCO) system is based on volume phase transmission holograms which exhibit minimum absorption, high diffraction efficiency, and adjustable dispersion. The spectral imaging properties of volume phase transmission holograms can be optimized with respect to the requirements for solar applications.

FAZYTAN: a system for fast automated cell segmentation, cell image analysis and feature extraction based on TV-image pickup and parallel processing.

Cell location, segmentation and feature extraction of cell images are principal tasks of a high-resolution system for automated cytology. To perform these tasks with high speed, image processing algorithms and the architecture of a processor have to be optimized mutually. This has led to the development of a fast system for the evaluation of cytologic samples based on an optimized TV microscope, a host minicomputer with different peripheral array processors and digital image storages. The processors are optimized in speed for two-dimensional local operations to investigate neighborhood relations and morphology in cell images. Two-dimensional transformations of TV images (288 x 512 x 8 bit) can be carried out within 20 to 200 msec. The processors are able to realize linear filter functions (correlation, convolution) as well as nonlinear functions (median filtering). A set of measurements like area, circumference and connectivity can be derived parallely from one image in 20 msec. The system performs efficient and fast detection and segmentation of cells scanned in one TV frame within one second as well as the extraction of a large number of morphologic features within a few seconds. Based on these procedures, high-resolution analysis of several thousand cells of a sample within one minute will be possible.

Structure analysis and classification of cervical cells using a processing system based on TV.

This paper presents preliminary results of a cell classification experiment using a new approach for feature extraction. The algorithm takes into account the special requirements of a fast parallel processing system (processor-oriented algorithms). A cell image is described by several hundred features derived from the nucleus only. The most significant features with respect to classification are determined by statistical analysis. Applying principal axis transform, a new feature set is computed, reduced considerably in dimensions. The data base (1,925 cell images of Papanicolaou-stained cervical specimens) was divided into a training set (963 images) and a test set (962 images). The classification results of the test set show that the recognition rate for the two-class problem (normal, suspicious) is better than 91%, using only ten morphologic features.