Search results for "Left ventricle"
showing 10 items of 20 documents
MR-tomographische Funktionsanalyse des linken Ventrikels
1993
The following contribution presents a continuous MRT analysis of the contraction and relaxation processes of healthy left ventricles giving reference values for contraction and relaxation velocities. For the total ventricle we have Vsyst. r. total = 342 +/- 47% LVEDV/sec and Vdiast. r. total = 303 +/- 59% LVEDV/sec. In relation to the end-diastolic (tomographic) volume (EDSV) significantly greater changes in volume per unit of time were measured apically compared to basal (systolic: 411 +/- 89% EDSV/sec apical vs 261 +/- 35% EDSV/sec basal; diastolic: 810 +/- 145% EDSV/sec apical vs 245 +/- 70% EDSV/sec basal). Occurrence of the end-systolic minimal volumes of apical tomographic layers was …
Quantitative study of cardiac wall motion from cine-MRI using frequency-based optical flow methods
2010
The aim of this thesis is to study parietal desynchronisation of the left ventricle from conventional cine-MRI. The first part of our work consisted in the quantification of the left ventricle wall motion of the heart directly from conventional retrospective SSFP type cine-MRI sequences used in the study of cardiac function. The developed methods for measuring displacements within the images are frequency-based optical flow methods. These techniques seem to be particularly adapted to MRI specificities. We have demonstrated their robustness in the event of Rician noise and pixel intensity variations as a function of time. These variations are often associated with the through-plane motion of…
Cardiac Magnetic Resonance with Delayed Enhancement of the Right Ventricle in patients with Left Ventricle primary involvement: diagnosis and evaluat…
2020
: Cardiac Magnetic Resonance (CMR) allows an accurate Right Ventricle (RV) assessment that could be of great relevance in diseases causing inflammation or fibrosis. The aim of this study was to evaluate the concomitant involvement of the RV in patients with delayed enhancement (DE) of the Left Ventricle (LV-DE) using CMR. We retrospectively enrolled 95 (male n. 66; age 55±18years; BMI 26±5kg/m2) consecutive patients with LV-DE who underwent a CMR (Achieva 1.5 T, Philips) for different indications: post-ischemic dilated cardiopathy (PDM), hypertrophic cardiomyopathy (HCM), myocardial infarction (MI), myocarditis/pericarditis (MP) and congenital heart disease (CD). We assessed the presence an…
PSPU-Net for Automatic Short Axis Cine MRI Segmentation of Left and Right Ventricles
2020
[EN] Characterization of the heart anatomy and function is mostly done with magnetic resonance image cine series. To achieve a correct characterization, the volume of the right and left ventricle need to be segmented, which is a timeconsuming task. We propose a new convolutional neural network architecture that combines U-net with PSP modules (PSPU-net) for the segmentation of left and right ventricle cavities and left ventricle myocardium in the diastolic frame of short-axis cine MRI images and compare its results against a classic 3D U-net architecture. We used a dataset containing 399 cases in total. The results showed higher quality results in both segmentation and final volume estimati…
Automatic left ventricle volume calculation with explainability through a deep learning weak-supervision methodology
2021
[EN] Background and objective: Magnetic resonance imaging is the most reliable imaging technique to assess the heart. More specifically there is great importance in the analysis of the left ventricle, as the main pathologies directly affect this region. In order to characterize the left ventricle, it is necessary to extract its volume. In this work we present a neural network architecture that is capable of directly estimating the left ventricle volume in short axis cine Magnetic Resonance Imaging in the end-diastolic frame and provide a segmentation of the region which is the basis of the volume calculation, thus offering explain-ability to the estimated value. Methods: The network was des…
RELEASE OF CATECHOLAMINES FROM THE HEART
1966
Publisher Summary This chapter discusses the release of catecholamines from the heart. The isolated heart of the rabbit with the sympathetic nervous supply from the right stellate ganglion intact was set up according to Hukovio and Muscholl. The ganglion was stimulated for 30 s at supramaximal voltage with rectangular impulses of 3–5 ms duration a frequency of 10 shocks/s. Each stimulation period was followed by a resting period of 30 s. In the rabbit, four doses of 50 mg/kg l-α-methyldopa decreased the noradrenaline concentration in auricles, right, and left ventricles by 38–60%. An equimolar amount of α-methyl noradrenaline was detected in the tissues. Reserpine and guanethidine in doses,…
Cardiac Injury in COVID-19–Echoing Prognostication∗
2020
Background Myocardial injury is frequent among patients hospitalized with coronavirus disease-2019 (COVID-19) and is associated with a poor prognosis. However, the mechanisms of myocardial injury remain unclear and prior studies have not reported cardiovascular imaging data. Objectives This study sought to characterize the echocardiographic abnormalities associated with myocardial injury and their prognostic impact in patients with COVID-19. Methods We conducted an international, multicenter cohort study including 7 hospitals in New York City and Milan of hospitalized patients with laboratory-confirmed COVID-19 who had undergone transthoracic echocardiographic (TTE) and electrocardiographic…
Metabolic syndrome, organ damage and cardiovascular disease in treated hypertensive patients. The ERIC‐HTA study
2007
The aim of this study is to assess the relationship among metabolic syndrome (MS), target organ damage (TOD) and established cardiovascular disease (CVD) in non-diabetic hypertensive elderly patients. ERIC-HTA is cross-sectional, multicentre study carried out in primary care, on hypertensive patients aged 55 or older. MS was defined by the NCEP-ATP III criteria, using body mass index (28.8 kg/m(2)) instead of abdominal perimeter. In 8331 non-diabetic hypertensive patients (3663 men and 4668 women, mean age 67.7 years), the prevalence of MS was 32.6% (men: 29.0%; women: 36.8%). A linear association was observed between a greater number of components of MS and a greater prevalence of left ven…
Incidence, risk factors, and thrombotic load of pulmonary embolism in patients hospitalized for COVID-19 infection
2021
Summary Objective To determine the incidence, characteristics, and risk factors of pulmonary embolism (PE) among patients hospitalized for COVID-19. Patients and Methods We performed a prospective observational study of a randomly selected cohort of consecutive patients hospitalized for COVID-19 infection between March 8, 2020 through April 25, 2020. All eligible patients underwent a computed tomography pulmonary angiography independently of their PE clinical suspicion and were pre-screened for a baseline elevated D-dimer level. Results 119 patients were randomly selected from the 372 admitted to one tertiary hospital in Valencia (Spain) for COVID-19 infection during the period of study. Se…
Tomographic left ventricular volume determination in the presence of aneurysm by three-dimensional echocardiographic imaging. I: Asymmetric model hea…
1996
To improve the accuracy of measurements of left ventricular volume in the presence of an aneurysm, we used three-dimensional echocardiographic imaging to analyze the shape of left ventricles in 23 asymmetric model hearts with eccentric aneurysms of different sizes, shapes, and localizations. A standard 3.75 MHz ultrasound probe with a rotation motor device was used to obtain a three-dimensional data set. By rotating the probe stepwise 1 degree, 180 radial ultrasound pictures were digitized. On the basis of the three-dimensional data set, the following parameters were determined and compared with the dimensions of the model hearts obtained by direct measurement: total left ventricular volume…