Biomedical subjects

A Baskurt

Publications and source records attributed to A Baskurt.

6 recordsLinked to original sources

PubMed2001

Perfusion-based segmentation of the human brain using similarity mapping.

In this work, a method for segmenting human brain MR scans on the basis of perfusion is described. This technique uses a measure of similarity between the time-intensity curves obtained with dynamic susceptibility contrast-enhanced MRI and a modeled curve of reference to isolate a tissue of interest, such as white or gray matter. The aim of this study was to validate the method by performing segmentation of white and gray matter in six controls. The relative regional blood volume gray-to-white matter ratio was used as a criterion to assess the quality of segmentation. On average, this ratio was 2.1 +/- 0.2, which is in good agreement with the literature, thus suggesting reliable segmentation. In the case of abnormal perfusion, time-intensity curves are different in shape than that of normal tissue. Therefore, this approach might allow the segmentation of pathological regions, and combined with an indicator-dilution analysis might offer new possibilities for characterizing a brain pathology. Magn Reson Med 45:261-268, 2001.

Brain↗

PubMed2001

A multiparametric and multiresolution segmentation algorithm of 3-D ultrasonic data.

An algorithm devoted to the segmentation of 3-D ultrasonic data is proposed. The algorithm involves 3-D adaptive clustering based on multiparametric information: the gray-scale intensity of the echographic data, 3-D texture features calculated from the envelope data, and 3-D tissue characterization information calculated from the local frequency spectra of the radio-frequency signals. The segmentation problem is formulated as a Maximum A posterior (MAP) estimation problem. A multi-resolution implementation of the algorithm is proposed. The approach is tested on simulated data and on in vivo echocardiographic 3-D data. The results presented in the paper illustrate the robustness and the accuracy of the proposed approach for the segmentation of ultrasonic data.

Algorithms↗

PubMed1999

CARDIOMEDIA: a communicable multimedia medical record on Intranet and digital optical memory card.

As part of French health reform, French physicians were computerised by the end of 1998. A specific Intranet network will be used to communicate medical data between the health professionals. The objectives of the CARDIOMEDIA project were to develop and evaluate the feasibility of a coronary multimedia data record stored on an optical card and communicable on Intranet within the hospital. Patients treated by angioplasty at the University Hospital of Rennes participated in the experiment. In general, patients are treated in the University Hospital and are followed up by another health care provider closer to their home. The patient leaves the University Hospital with his card, which is directly available elsewhere for emergency or for consultation. This approach is assumed to reduce the number of examinations and to offer a better patient follow-up. The CARDIOMEDIA card is a specialised record including various data types: text, images, image sequences of coronarography and ECG signals. For this purpose an optical card with its large memory is very convenient. We used the DICOM format for image exchange and management. It is combined with CARDIOMEDIA specific compressing software. For the multimedia record the HTML format and web Intranet method are chosen. This provides an intuitive interface which can combine various data types and helper applications like a DICOM image viewer.

Angioplasty↗

PubMed1998

Multiresolution texture based adaptive clustering algorithm for breast lesion segmentation.

OBJECTIVE: A specific algorithm is presented for the automatic extraction of breast tumors in ultrasonic imaging. METHOD: The algorithm involves two-dimensional adaptive K-means clustering of the gray scale and textural feature images. The segmentation problem is formulated as a maximum a posteriori (MAP) estimation problem. The MAP estimation is achieved using Besag's iterated conditional modes algorithm for the minimization of an energy function. This function has three components: the first constrains the region to be close to the data; the second imposes spatial continuity; and the third takes into consideration the texture of the various regions. A multiresolution implementation of the algorithm is performed using a waveless basis. RESULTS: Experiments were carried out on synthetic images and on in vivo breast ultrasound images. Various parameters involved in the algorithm are discussed to evaluate the robustness and accuracy of the segmentation method. CONCLUSION: Including textural features in the segmentation of ultrasonic data improves the robustness of the algorithm and makes the segmentation result less parameter dependent.

Adenocarcinoma↗

PubMed1997

Cardiomedia: a multimedia portable medical record on optical memory card.

The main objective of the CARDIOMEDIA project is to produce and evaluate a coronarian multimedia data record stored on an optical card. The experimentation concerns patients treated by angioplasty at university hospital of Rennes. Often patients treated in the Regional University Hospital are followed up by another Health structure closer to their home. The patient leaves hospital with his card, which is directly available elsewhere for emergency or for consultation. This will optimize the number of examinations and offer a better patient follow-up. The CARDIOMEDIA card is a specialized record which includes various data type: text, image, image sequence of coronarography and ECG signal. For this purpose optical card with its large memory size is very convenient. For medical imaging, we use in this project the DICOM format for image exchange and management, it is combined with a CARDIOMEDIA specific compressing software. For multimedia record, the HTML format and web intranet method are chosen, this allows intuitive interface which can combine various data type and helpers like DICOM image viewer.

Cardiovascular Diseases↗

PubMed1996

ROC assessment of compressed wrist radiographs.

The aim of this paper is to validate a compression scheme applied on a medical image database of digitized wrist radiographs. The compression scheme adapts itself to local statistical properties of the images. The diagnostic quality of the reconstructed images is evaluated using a ROC protocol involving five medical experts. The results of this evaluation enable us to validate the compression scheme on this database with a compression ratio of 40 (0.2 bits per pixel).

Humans↗