Search results for "Spectroscopy"
showing 10 items of 10293 documents
MUSCLE BIOENERGETICS IN OBESE ZUCKER RATS
1994
International audience; Abstract: The purpose of this study was to investigate the energetic metabolism in obese Zucker rats, using phosphorus nuclear magnetic resonance spectroscopy at rest and during a 2-Hz muscle stimulation and subsequent recovery. Animals were anesthetized with ketamine (150 mg/kg ip). Fed obese rats and 2-day-fasted obese rats were compared with their normally fed and 2-day-fasted lean litter mates. No differences were found between the two groups for ATP, total creatine, phosphocreatine (PCr), and intracellular pH. Starvation in lean rats resulted in a significant fall in inorganic phosphate (Pi), increased resting ADP level, and decreased PCr and ADP recovery after …
Magnetic Resonance Assessment of Left Ventricular Ejection Fraction at Any Time Post-Infarction for Prediction of Subsequent Events in a Large Multic…
2021
Background Magnetic resonance imaging (MRI) is the most accurate imaging technique for left ventricular ejection fraction (LVEF) quantification, but as yet the prognostic value of LVEF assessment at any time after ST-segment elevation myocardial infarction (STEMI) for subsequent major adverse cardiac event (MACE) prediction is uncertain. Purpose To explore the prognostic impact of MRI-derived LVEF at any time post-STEMI to predict subsequent MACE (cardiovascular death or re-admission for acute heart failure). Study Type Prospective. Population One thousand thirteen STEMI patients were included in a multicenter registry. Field Strength/Sequence 1.5-T. Balanced steady-state free precession (c…
Patent Foramen Ovale and Thromboembolic Complications
2010
The foramen ovale, an atrial septal defect which is essential in the fetal circulation, remains patent through adulthood in approximately 25% of the general population and so it represents the most common persistent abnormality of fetal origin. Patent foramen ovale (PFO) allows interatrial right-to-left blood shunting during those periods of the cardiac cycle in which the right atrial pressure exceeds the left one. An increasing number of pathological manifestations of PFO has been recently identified; among these, paradoxical systemic embolism, refractory hypoxemia in patients with right ventricular myocardium infarction or severe pulmonary disease, orthostatic oxygen desaturation in the r…
Long-term prognostic implications of revascularization in patients with known or suspected chronic coronary syndromes without ischemia in vasodilator…
2021
In this study, we evaluated the association between symptoms-guided revascularization occurred within three months following a negative vasodilator stress cardiovascular magnetic resonance (negative stress-CMR) and long-term adverse events in patients with known or suspected chronic coronary syndrome (CCS).We retrospectively evaluated 3517 patients in which the stress first-pass perfusion imaging revealed no ischemia. The primary endpoint was the composite of death, spontaneous myocardial infarction, heart failure (HF), or stroke. The association between symptoms-guided revascularization after a negative stress-CMR and the endpoint was assessed using the multivariable Cox proportional hazar…
Stress cardiac magnetic resonance for mortality prediction and decision-making: registry of 2496 elderly patients with chronic coronary syndrome
2022
Abstract Introduction and objectives The management of elderly patients with chronic coronary syndrome (CCS) is challenging. We explored the prognostic value and usefulness for decision-making of ischemic burden determined by vasodilator stress cardiac magnetic resonance (CMR) imaging in elderly patients with known or suspected CCS. Methods The study group comprised 2496 patients older than 70 years who underwent vasodilator stress CMR for known or suspected CCS. The ischemic burden (number of segments with stress-induced perfusion deficit) was calculated following the 17-segment model. Subsequently, we retrospectively analyzed its association with all-cause mortality and the effect of CMR-…
Magnesium metabolism in hypertension and type 2 diabetes mellitus.
2007
The increasing evidence for the clinical relevance of altered magnesium metabolism to states of altered insulin resistance confirms the role of magnesium deficit as a possible underlying common mechanism of the "insulin resistance" of hypertension and altered glucose tolerance. The pioneer work of Lawrence M. Resnick and his group using the cellular ion-based approach that we are only partially presenting here has consistently contributed to the progress of the field, demonstrating (a) the critical importance of magnesium metabolism in regulating insulin sensitivity as well as vascular tone, and blood-pressure homeostasis; (b) that magnesium deficiency, defined on the basis of intracellular…
Diffuse reflectance and fluorescence multispectral imaging system for assessment of skin
2014
The diffuse reflectance multispectral imaging technique has been used for distant mapping of in vivo skin chromophores (hemoglobin and melanin). The fluorescence multispectral imaging is not so common for skin applications due to complicity of data acquisition and processing, but could provide additional information about skin fluorophores. Both techniques are compatible, and could be combined into a multimodal solution. The multispectral imaging system Nuance based on liquid crystal tunable filters was adapted for diffuse reflectance and fluorescence spectral imaging of in vivo skin. Uniform illumination was achieved by LED ring light. Combination of four LEDs (warm white, 770 nm, 830 nm a…
Water detection in skin by dual-band photodiodes
2013
Purpose of this study was to develop a simple model for possibilities to detect water in skin by diffuse reflectance spectra. The model is based on comparison of diffuse reflectance spectra when illuminating water sample with LEDs of different wavelengths (1200 nm, and 1450 nm). The illumination LEDs were chosen due to water absorption differences in near-infrared spectral range. For detection, dual-band photodiode DSD2 by Thorlabs was used. Due to differences of water absorption at different wavelengths in the near-infrared spectral region, this correlation could be used for mapping of water content in skin or, in other words, determine relative moisture level in skin. Simple experimental …
Skin haemoglobin mapping: comparison of multi-spectral imaging and selective R-G-B analysis
2010
The multi-spectral imaging technique has been used for distant mapping of in-vivo skin haemoglobin. Besides, potential of selective R-G-B analysis of skin images has been studied under bi-chromatic (532 nm and 635 nm) laser illumination.
Determination of chromophore distribution in skin by spectral imaging
2012
Possibilities to determine chromophore distribution in skin by spectral imaging were explored. Simple RGB sensor devices were used for image acquisition. Totally 200 images of 40 different bruises of 20 people were obtained in order to map chromophores bilirubin and haemoglobin. Possibilities to detect water in vitro and in vivo were estimated by using silicon photodetectors and narrow band LEDs. The results show that it is possible to obtain bilirubin and haemoglobin distribution maps and observe changes of chromophore parameter values over time by using a simple RGB imaging device. Water in vitro was detected by using differences in absorption at 450 nm and 950 nm, and 650 nm and 950 nm.