Hernan Mella

Hernan Mella
Pontificia Universidad Católica de Valparaíso | PUCV · School of Electrical Engineering

Ph.D.

About

22
Publications
2,186
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8
Citations
Introduction
My research interests are related to developing processing and acquisition techniques of Magnetic Resonance images to improve the assessment of the heart and other organs' function.
Education
August 2016 - March 2021
Pontificia Universidad Católica de Chile
Field of study
  • Electrical Engineering
March 2011 - July 2016

Publications

Publications (22)
Article
Full-text available
Background and Purpose: Prognostic models based on cardiovascular hemodynamic parameters may bring new information for an early assessment of bicuspid aortic valve (BAV) patients, playing a key role in reducing the long-term risk of cardiovascular events. This work quantifies several three-dimensional hemodynamics parameters in different BAV patien...
Article
Full-text available
4D Flow Magnetic Resonance Imaging (MRI) is the state‐of‐the‐art technique to comprehensively measure the complex spatio‐temporal and multidirectional patterns of blood flow. However, it is subject to artifacts such as noise and aliasing, which due to the 3D and dynamic structure is difficult to detect in clinical practice. In this work, a new math...
Article
Pulse Wave Velocity (PWV) corresponds to the velocity at which pressure waves, generated by the systolic contraction in the heart, propagate along the arterial tree. Due to the complex interplay between blood flow and the artery wall, PWV is related to inherent mechanical properties and arterial morphology. PWV has been widely accepted as a biomark...
Article
Purpose Three-dimensional (3D) quantification of circulation using a Finite Elements methodology. Methods We validate our 3D method using an in-silico arch model, for different mesh resolutions, image resolution and noise levels, and we compared this with a currently used 2D method. Finally, we evaluated the application of our methodology in 4D Fl...
Thesis
Cardiac MRI is a valuable tool for studying cardiac function. Particularly, cardiac tagging MRI combined with advanced processing techniques allows the estimation of the tissue motion and strain, which could help for an early assessment of several diseases. However, state-of-the-art tagging sequences and processing methods suffer from several issue...
Article
Full-text available
We addressed comprehensively the performance of Shortest-Path HARP Refinement (SP-HR), SinMod, and DENSEanalysis using 2D slices of synthetic CSPAMM and DENSE images with realistic contrasts obtained from 3D phantoms. The three motion estimation techniques were interrogated under ideal and no-ideal conditions (with MR induced artifacts, noise, and...
Article
Full-text available
Purpose: To develop an Off-Resonance Insensitive Orthogonal CSPAMM sequence for the acquisition of CSPAMM and MICSR grids in half of the acquisition time. Methods: Phantom and mid-level LV short-axis tagged images were acquired using CSPAMM, ORI-CSPAMM, O-CSPAMM, and the proposed ORI-O-CPAMM sequences to interrogate and compare its behavior under o...
Preprint
Full-text available
Purpose: To develop an Off-Resonance Insensitive Orthogonal CSPAMM sequence for the acquisition of CSPAMM and MICSR grids in half of the acquisition time. Methods: Phantom and mid-level LV short-axis tagged images were acquired using CSPAMM, ORI-CSPAMM, O-CSPAMM, and the proposed ORI-O-CPAMM sequences to interrogate and compare its behavior under o...
Article
Full-text available
We proposed a novel method called HARP-I, which enhances the estimation of motion from tagged Magnetic Resonance Imaging (MRI). The harmonic phase of the images is unwrapped and treated as noisy measurements of reference coordinates on a deformed domain, obtaining motion with high accuracy using Radial Basis Functions interpolations. Results were c...
Preprint
Full-text available
We proposed a novel method called HARP-I, which enhances the estimation of motion from tagged Magnetic Resonance Imaging (MRI). The harmonic phase of the images is unwrapped and treated as noisy measurements of reference coordinates on a deformed domain, obtaining motion with high accuracy using Radial Basis Functions interpolations. Results were c...
Conference Paper
Full-text available
In this work, we introduce the Phase Complementary Spatial Modulation of Magnetization (PCSPAMM) acquisition sequence, designed to measure the tissue motion simultaneously with the flow velocity. With a pair of complementary acquisitions, PCSPAMM allows the estimation of a CSPAMMand a Phase-Contrast (PC) MR image, leading to improved tagging contra...
Conference Paper
Full-text available
The circulation is normally analyzed in a 2D cross-section of the aorta, manually placed. To avoid this problem, evaluate and validate a new methodology based on Finite Elements (FE) to calculate the circulation in three-dimensions, in in-silico models, and in the ascending aorta of a group of volunteers and patients. In in-silico experiment, we ob...
Conference Paper
Full-text available
Tagging MR is still considered the gold standard for motion quantification in the heart walls. Although there are several methods for postprocessing this kind of images, harmonic phase methods such as HARP and SinMod has been widely used because of its simplicity and reliable results. In this work, we present a novel Harmonic Phase Interpolation (H...
Conference Paper
Full-text available
The generation of synthetic MR images allows the testing of several for postprocessing methodologies under controlled conditions. In this work, we developed an open source Python/C++ library for the generation of synthetic SPAMM, C-SPAMM and DENSE images, based on known magnetization expressions and using finite element geometries. Introduction Tag...
Presentation
The simulation of the propagation of elastic waves in unbounded domain is still an open problem. Different kinds of absorbing boundary conditions (ABC) has been introduced, such as Gaussian taper method, high-order ABC or paraxial approximations. Among them, one of the most successful approach is the perfectly matched layers (PML) method, introduce...
Conference Paper
Full-text available
The simulation of the propagation of elastic waves in unbounded domain is still an open problem. Different kinds of absorbing boundary conditions (ABC) has been introduced, such as Gaussian taper method, high-order ABC or paraxial approximations. Among them, one of the most successful approach is the perfectly matched layers (PML) method, introduce...

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Projects

Project (1)
Project
To improve the tissue's strain estimation by developing novel strategies for the scanning and processing of MR images