Search for: heart-left-ventricle
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    MFP-Unet: A novel deep learning based approach for left ventricle segmentation in echocardiography

    , Article Physica Medica ; Volume 67 , 2019 , Pages 58-69 ; 11201797 (ISSN) Moradi, S ; GhelichOghli, M ; Alizadehasl, A ; Shiri, I ; Oveisi, N ; Oveisi, M ; Maleki, M ; Dhooge, J ; Sharif University of Technology
    Associazione Italiana di Fisica Medica  2019
    Segmentation of the Left ventricle (LV) is a crucial step for quantitative measurements such as area, volume, and ejection fraction. However, the automatic LV segmentation in 2D echocardiographic images is a challenging task due to ill-defined borders, and operator dependence issues (insufficient reproducibility). U-net, which is a well-known architecture in medical image segmentation, addressed this problem through an encoder-decoder path. Despite outstanding overall performance, U-net ignores the contribution of all semantic strengths in the segmentation procedure. In the present study, we have proposed a novel architecture to tackle this drawback. Feature maps in all levels of the decoder... 

    The role of hippo signaling pathway in physiological cardiac hypertrophy

    , Article BioImpacts ; Volume 10, Issue 4 , 2020 , Pages 251-257 Gholipour, M ; Tabrizi, A ; Sharif University of Technology
    Tabriz University of Medical Sciences  2020
    Introduction: The role of Hippo signaling pathway, which was identified by genetic studies as a key regulator for tissue growth and organ size, in promoting physiological cardiac hypertrophy has not been investigated. Methods: Fourteen male Wistar rats were randomly assigned to the exercise and control groups. The exercise group ran 1 hour per day, 5 days/week, at about 65%-75% VO2max on the motor-driven treadmill with 15ºslope, and the control group ran 15 min/d, 2 days/ week at 9 m/min (0ºinclination), throughout the eight-week experimental period. Forty-eight hours after the last session, hearts were dissected and left ventricles were weighed and stored for subsequent RT-PCR analysis.... 

    An optimized probabilistic edge based level set method for left ventricle segmentation in echocardiography images

    , Article Biomedical Research (India) ; Volume 28, Issue 8 , 2017 , Pages 3788-3793 ; 0970938X (ISSN) Sahba, N ; Fatemizadeh, E ; Behnam, H ; Sharif University of Technology
    Scientific Publishers of India  2017
    In this paper, an efficient approach for ultrasonic object segmentation with special application for left ventricle segmentation in echocardiography images is proposed. At first, an efficient hybrid trend for ultrasonic image edge detection is suggested. Then, a modified level set approach is introduced based on the extracted edges and the computed probabilistic map as the stopping criteria for the contour evolution. Both synthetic and clinical images are utilized as validation measures with respect to the prior techniques which indicate outperform results quantitatively and qualitatively. Left ventricle segmentation using proposed method illustrates expert-approved performance, providing a... 

    Investigation of the effect of high +Gz accelerations on human cardiac function

    , Article Journal of the Mechanical Behavior of Biomedical Materials ; Volume 27 , 2013 , Pages 54-63 ; 17516161 (ISSN) Jamshidi, M ; Ahmadian, M. T ; Sharif University of Technology
    This study investigates the effect of body acceleration on human cardiac function. Finite element analysis is conducted to simulate geometrical and mechanical properties of human heart. Heart geometrical modeling in three-dimension is performed by segmentation of cardiac MRI images. The nonlinear mechanical behavior of myocardium is modeled by Mooney-Rivlin, Polynomial, Ogden and Yeoh hyperelastic material models. Stress-strain curves of myocardial tissue are obtained from experimental compression tests on bovine heart samples. The experimental results are employed for the evaluation of material coefficients by the nonlinear least squares method. Among hyperelastic models, the Yeoh model... 

    Role of endurance training in preventing pathological hypertrophy via large tumor suppressor (LATS) changes

    , Article Iranian Heart Journal ; Volume 20, Issue 3 , 2019 , Pages 52-59 ; 17357306 (ISSN) Tabrizi, A ; Soori, R ; Choobineh, S ; Gholipour, M ; Sharif University of Technology
    Iranian Heart Association  2019
    Background: One of the negative effects of cardiac sympathetic hyperactivity is pathologic hypertrophy. Recent studies have indicated that large tumor suppressor (LATS) is one of the molecules which play a critical role in cardiomyocyte apoptosis. Considering the preventive role of exercise training, we evaluated the effects of endurance training on LATS gene expression and its upstream pathway in the present study. Methods: Eighteen male Wistar rats were randomly divided into 2 groups: Endurance and control. Endurance training was performed for 8 weeks, 1 hour per day, and 6 days per week on the treadmill at a 15° inclination. Pathologic hypertrophy was induced with the injection of 3... 

    Spatiotemporal registration and fusion of transthoracic echocardiography and volumetric coronary artery tree

    , Article International Journal of Computer Assisted Radiology and Surgery ; Volume 16, Issue 9 , 2021 , Pages 1493-1505 ; 18616410 (ISSN) Ghodsizad, T ; Behnam, H ; Fatemizadeh, E ; Faghihi Langroudi, T ; Bayat, F ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Purpose: Cardiac multimodal image fusion can offer an image with various types of information in a single image. Many coronary stenosis, which are anatomically clear, are not functionally significant. The treatment of such kind of stenosis can cause irreversible effects on the patient. Thus, choosing the best treatment planning depend on anatomical and functional information is very beneficial. Methods: An algorithm for the fusion of coronary computed tomography angiography (CCTA) as an anatomical and transthoracic echocardiography (TTE) as a functional modality is presented. CCTA and TTE are temporally registered using manifold learning. A pattern search optimization algorithm, using... 

    Experimental feasibility study of estimation of the normalized central blood pressure waveform from radial photoplethysmogram

    , Article Journal of Healthcare Engineering ; Volume 6, Issue 1 , 2015 , Pages 121-144 ; 20402295 (ISSN) Zahedi, E ; Sohani, V ; Mohd. Ali, M. A ; Chellappan, K ; Beng, G. K ; Sharif University of Technology
    Multi-Science Publishing Co. Ltd  2015
    The feasibility of a novel system to reliably estimate the normalized central blood pressure (CBPN) from the radial photoplethysmogram (PPG) is investigated. Right-wrist radial blood pressure and left-wrist PPG were simultaneously recorded in five different days. An industry-standard applanation tonometer was employed for recording radial blood pressure. The CBP waveform was amplitude-normalized to determine CBPN. A total of fifteen second-order autoregressive models with exogenous input were investigated using system identification techniques. Among these 15 models, the model producing the lowest coefficient of variation (CV) of the fitness during the five days was... 

    Cardiac contraction motion compensation in gated myocardial perfusion SPECT: a comparative study

    , Article Physica Medica ; Volume 49 , 2018 , Pages 77-82 ; 11201797 (ISSN) Salehi, N ; Rahmim, A ; Fatemizadeh, E ; Akbarzadeh, A ; Farahani, M. H ; Farzanefar, S ; Ay, M. R ; Sharif University of Technology
    Associazione Italiana di Fisica Medica  2018
    Introduction: Cardiac contraction significantly degrades quality and quantitative accuracy of gated myocardial perfusion SPECT (MPS) images. In this study, we aimed to explore different techniques in motion-compensated temporal processing of MPS images and their impact on image quality and quantitative accuracy. Material and method: 50 patients without known heart condition underwent gated MPS. 3D motion compensation methods using Motion Freezing by Cedars Sinai (MF), Log-domain Diffeomorphic Demons (LDD) and Free-Form Deformation (FFD) were applied to warp all image phases to fit the end-diastolic (ED) phase. Afterwards, myocardial wall thickness, myocardial to blood pool contrast, and...