0000000000195033
AUTHOR
E. Steinmetz
Quantitative comparison of new image processing methods for volumetric analysis of left ventricular contrast echocardiograms
An effort has been made to develop image processing methods which allow a definite and precise tracking of the borderline of the ventricle in two-dimensional echocardiograms. Experience is reported with two new methods, which are based on the gray-level rise (GL) and the signal-to-noise ratio (SNR) in combined heart-phase-triggered image series. A quantitative comparison of these time-series methods is presented with respect to the interpretation of a single native image (noncontrast image), a single contrast-material image, the corresponding subtraction image, and the corresponding color superposition image. The comparison is based on the calculation of the ejection fraction using the abov…
Infarctus du myocarde au cours de l’artérite à cellules géantes : étude de cohorte
Introduction Le risque d’evenement cardiovasculaire est accru au cours de l’arterite a cellules geantes (ACG), en particulier dans les premiers mois suivant le diagnostic de la vascularite [1] . L’objectif de ce travail etait de decrire les caracteristiques des infarctus du myocarde (IDM) survenant chez des patients atteints d’ACG et de les comparer avec des IDM survenant chez des patients ne presentant pas d’ACG au moment de leur IDM. Patients et methodes Les patients atteints d’ACG ont ete identifies parmi la liste des biopsies d’artere temporale (BAT) qui montraient des lesions d’ACG et qui avaient ete analysees entre le 1er janvier 2001 et le 31 decembre 2016 dans les deux laboratoires …
Echocardiographic Image Analysis Based on the Evaluation of first Order Speckle Statistics
Basic theoretical considerations on the statistical properties of the speckle phenomenon indicate that a conventional quantization (intervals of uniform width) of the received and envelope detected RF — signal is not adequate. We therefore propose a quantization scheme which is based on the application of quantization intervals producing always the same confidence level (adaptive quantization). The advantages are: homogenous distribution of speckle noise reduction to about 10 – 20 significant quantization levels (with neglectable loss of morphological information) quantitative measure (confidence level) of the separability of regions represented with different quantization levels. We furthe…
Enhanced detection of contrast regions in echocardiograms by adaptive quantization
The statistics of ultrasound echo images are governed by Rayleigh statistics. The authors derive some experimentally verifiable predictions of this theory, compare them with experimental results obtained from echocardiographic images, and derive a new color coding scheme, (adaptive quantization) that is adapted to the signal-dependent noise predicted by theory. This results in some technical advantages and in an improved discrimination of regions of the echo image that are enhanced by echo contrast material. >
Comparison of Statistical Methods for the Detection of Contrast Material in Echocardiographic Image Sequences
Ultrasonic imaging of the heart is a diagnostic tool which is increasingly used in cardiology. In addition to the representation of important anatomical information two dimensional images provided by mechanical or electronically steered sector scanners can be used for the extraction of functional parameters of the heart (as e.g. enddiastolic volume or ejection fraction). A poor definition of the endocardial border especially resulting from the noisy appearance of the images and from qualitatively restricted echocardiograms leads to uncertainties in the quantitative analysis and therefore requires refined methods for the determination of functional parameters. Our investigations which are ba…