0000000000923506
AUTHOR
Paul Walker
showing 12 related works from this author
Incomplete resolution of ST-segment elevation is associated with severe microvasculatory dysfunction evaluated by magnetic resonance imaging
2004
International audience
The study of myocardial viability after myocardial infarction: Valve and limitations of magnetic resonance imaging compared with myocardial scintigra…
1997
International audience; Abstract: The aim of this study was to compare myocardial thickness measured by magnetic resonance imaging and quantified fixation of thallium. Twenty-one patients 61.2+/-11 years were investigated after myocardial infarction of the anterior wall in 8 cases, inferior in 10 cases, lateral in 2 cases and apical in one case. The mean angiographic ejection fraction was 46.5 +/- 19 %. Myocardial scintigraphy was performed after an exercise or pharmacological stress test and followed by a study of redistribution. The data was analysed by a quantitative method. Magnetic resonance imaging was performed with Vertical and horizontal long axis views in systole and diastole with…
Major Prognostic Impact of Persistent Microvascular Obstruction as Assessed by Contrast-Enhanced Cardiac Magnetic Resonance Imaging in the Setting of…
2008
International audience
Reduced brain N-acetyl-aspartate in frontal lobes suggests neuronal loss in patients with amyotrophic lateral sclerosis
1996
International audience; Abstract: We performed proton magnetic resonance spectroscopy (IH-MRS) in three patients with amyotrophic lateral sclerosis (ALS) to evaluate the distribution and extent of cortical neuronal damage as demonstrated by decreased N-acetyl-aspartate (NAA) levels. We examined primary motor (precentral gyrus) and parietal neocortical (superior parietal gyrus) regions. ALS was defined with lower and upper motor neuron signs. Compared with matched healthy controls, ALS patients had a significant decrease in NAA levels in the primary motor cortex (p<0.001) compared with parietal regions and homologous regions in healthy controls. Two clinical applications can be extracted: fi…
PROSTATEANALYZER: GUI ALLOWING THE MANAGEMENT OF EXAMINATIONS OF PROSTATE CANCER
2012
International audience; We propose a framework that comprises visualization and analysis for MR imaging of the prostate and a new storage system of clinical diagnoses in a single package. ProstateAnalyzer is such a network-based database system allowing the management of both MRI and spectroscopy data sets, and performing some basic mathematical operations to analyze a set of prostate images.
Incidence and Prognostic Impact of Persistent Microvascular Obstruction as Assessed by Cardiac Magnetic Resonance in the Setting of Non ST Segment El…
2009
International audience
Use of fuzzy techniques for the automatic identification of left ventricle contours from multi-slice short axis MR Imaging.
1997
International audience
MUSCLE BIOENERGETIC ABNORMALITY IN MYOTONIC-DYSTROPHY - A SECONDARY MITOCHONDRIAL DISORDER
1993
International audience; Abstract: The thenar muscles and gastrocnemius of a patient with myotonic dystrophy were investigated, at rest, by phosphorus nuclear magnetic resonance spectroscopy. A decrease in phosphocreatine level and an increase in inorganic phosphate and phosphodiester levels were found in the gastrocnemius, which was clinically spared, whilst the thenar muscles, which were wasted and affected by myotonia, exhibited only an increased inorganic phosphate level and an elevated pH. These findings were comparable with those found in other muscular disorders, such as Duchenne's and Becker's dystrophies, as well as in limb girdle dystrophy. They suggested that the abnormalities obs…
EFFECTS OF EXERCISE TRAINING AFTER MYOCARDIAL-INFARCTION ON MUSCULAR METABOLISM VALUE OF PHOSPHORUS 31 NMR-SPECTROSCOPY
1994
International audience; Abstract: P 31 NMR spectroscopy is a recent technique which allows a non-invasive and direct analysis of oxidative metabolism and pH changes, an indicator of acidosis due to lactic acid accumulation in the skeletal muscles. The authors investigated oxidative muscular metabolism of the sural triceps in 10 patients after myocardial infarction by performing a study after the acute phase and repeating the study after a programme of physical training. At rest, there were no significant differences. On the other hand, for the same level of maximal effort, the depletion in phosphocreatinine (PCr) and the accumulation of inorganic phosphate (Pi) were significantly lower afte…
MITOCHONDRIAL DISORDER SECONDARY TO INFLAMMATION IN POLYMYOSITIS - 2 CASES
1992
National audience; Abstract: Two cases of polymyositis were followed using phosphorus nuclear magnetic resonance spectroscopy. The spectra recorded during remission were normal, but those collected from the gastrocnemius muscle during the active phase of the diseases showed an increased inorganic phosphate level or a decreased phosphocreatine content. The intracellular pH was normal. These findings may be related to an impairment in mitochondrial metabolism secondary to the inflammatory process. Moreover, the fact that the abnormalities observed disappeared after treatment suggests that phosphorus NMR spectroscopy could be used as a non-invasive method in the follow-up of polymyositis, but …
Semi-automated labelling of medical images: benefits of a collaborative work in the evaluation of prostate cancer in MRI
2018
Purpose: The goal of this study is to show the advantage of a collaborative work in the annotation and evaluation of prostate cancer tissues from T2-weighted MRI compared to the commonly used double blind evaluation. Methods: The variability of medical findings focused on the prostate gland (central gland, peripheral and tumoural zones) by two independent experts was firstly evaluated, and secondly compared with a consensus of these two experts. Using a prostate MRI database, experts drew regions of interest (ROIs) corresponding to healthy prostate (peripheral and central zones) and cancer using a semi-automated tool. One of the experts then drew the ROI with knowledge of the other expert's…
NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY OF EXCISED HUMAN HEARTS
1992
International audience; Abstract: Background-Phosphorus nuclear magnetic resonance spectroscopy has been proposed as a method of studying the metabolism of the myocardium in patients. Little is known about P-31 nuclear magnetic resonance spectroscopy of diseased human hearts. Methods-Two donor hearts meeting the requirements for heart transplantation and 11 diseased hearts were removed during a transplantation procedure and were studied in a horizontal 2-35 T superconducting magnet. Spectra were obtained at 0-degrees-C about 30 minutes after the excision. The areas of the inorganic phosphate peak (Pi) and of the phosphocreatine peak (PCr) were summed and expressed as a ratio with respect to…