The MeDiTATe project will participate in the 14th European Fluid Mechanics Conference



The MeDiTATe project will be participating in the 14th European Fluid Mechanics Conference (EFMC14), that will take place in Athens, Greece on September 13-16, 2022.
Two of our Early Stage Researchers, Bhargav Krishna Chitneedi and Christos Karliampas, will be presenting their activities at this Conference. A short summary of their work is reported in the following lines.
Bhargav Krishna Chitneedi – ESR 04: Numerical Prediction of Blood Flow in Arteries, Interacting with Walls, on GPUs. In this article, a framework for the Fluid-Structure Interactions (FSI) simulations of vascular blood flows, running on Graphics Processing Units (GPUs) is presented. The FSI simulations are performed, based on the partitioned approach, with the GPU-enhanced Finite Volume CFD code, PUMA (developed by the PCOpt/NTUA) for fluids, coupled with the open-source finite element solver, CalculiX, for the vessel walls. The flow is assumed to be laminar, and the non-Newtonian behaviour of the blood is represented using the Carreau model. The isotropic linear elastic model of CalculiX is used for the arterial wall computations. The GPUs are used for the flow simulation, which is expensive because of using fine mesh with boundary layers at wall vicinity. The structural analysis uses much coarser meshes and runs inexpensively on the CPU. The Precice coupling framework is used which also enables using non-matching timesteps and non-matching meshes to perform FSI simulations. The temporal velocity profile at the inlet and the 3-element Windkessel pressure model at the outlet are imposed. The FSI simulations are performed on patient-specific geometries of thoracic aorta with realistic flow conditions. The hemodynamic metrics like wall shear stresses are computed to predict the rupture prone areas which helps medical experts to take an informed decision to improve healthcare.
Christos Karliampas – ESR 06: Hemodynamic simulation of the thoracic aorta in the presence of uncertainties, using a reduced-order polynomial chaos expansion. The purpose of this paper is to investigate the sensitivity of the inlet flow profile in cardiovascular simulations of thoracic aorta. Due to limited, poor quality, patients’ data, it is a compromise to resort to idealized spatially distributed velocity profiles as the inlet boundary condition in undertaken simulations. This assumption introduces uncertainties, affecting the numerical solution in the entire fluid domain. Here, Womersley number is chosen to parameterize the imposed inlet velocity and a fast reconstruction method is proposed, based on the proper orthogonal decomposition polynomial chaos expansion, to analyze the velocity profile uncertainty propagation on the hemodynamic metrics.”
The MeDiTATe project at the VPH 2022 Conference



The MeDiTATe project will be participating in the VPH 2022 – Virtual Physiological Human Conference that will be held in Porto from 6th to 9th September 2022.
Two of our Early Stage Researchers, Antonio Martinez Pascual and Martino Andrea Scarpolini, will be presenting their work described in the following sections.
Antonio Martinez Pascual – ESR 01: Impact of Image Segmentation Variability on Hemodynamic Prediction of Flow Quantities in AAA. Computational fluid dynamics (CFD) can be used to compute various hemodynamic factors for abdominal aortic aneurysms (AAA), which may be used to assist with the risk assessment. Variability in the shape of the AAA lumen may arise during segmentation of the lumen wall from the medical image data. The resulting variation in local geometrical factors, such as the diameter and curvature, may impact the rupture prediction. Therefore, this study aims to estimate the effect of geometric uncertainty due to the segmentation process on WSS and wall pressure predictions.
Martino Andrea Scarpolini – ESR 09: A correlation study between morphological parameters and hemodynamics indices: an integrated deep learning and statistical shape modeling approach.
Deep Learning (DL) has been demonstrated to be a promising tool to estimate hemodynamic indices in several cardiovascular districts. Statistical shape (SS) analysis, on the other hand, is an established tool to quantitatively assess geometric variability. In this work, these two methods are combined to develop a real-time estimation method for hemodynamic indices of the whole thoracic aorta.
A new MeDiTATe Project publication: Towards the 2D velocity reconstruction in abdominal aorta from Color-Doppler Ultrasound

Maria Nicole Antonuccio, ESR 14 of the MeDiTATe project, published the paper titled Towards the 2D velocity reconstruction in abdominal aorta from Color-Doppler Ultrasound in Medical Engineering & Physics Journal.
The work was developed in collaboration with Hernan G. Morales, Alexandre This and Laurence Rouet from Philips Research Paris, Katia Capellini and Simona Celi from BioCardioLab (Fondazione Toscana G. Monasterio), Stéphane Avril from Mines Saint-Étienne.
The paper whose abstract is reported in the following lines, is available at this link.
Magnetic resonance imaging (MRI) is the preferred modality to assess hemodynamics in healthy and diseased blood vessels. As an affordable and non-invasive alternative, Color-Doppler imaging is a good candidate. Nevertheless, Color-Doppler acquisitions provide only partial information on the blood velocity within the vessel. We present a framework to reconstruct 2D velocity fields in the aorta. We generated 2D Color-Doppler-like images from patient-specific Computational Fluid Dynamics (CFD) models of abdominal aortas and evaluated the framework’s performance. The 2D velocity field reconstruction is based on the minimization of a cost function, in which the reconstructed velocities are constrained to satisfy fluid dynamics principles. The numerical evaluations show that the reconstructed vector flow fields agree with ground-truth velocities, with an average magnitude error of less than and an average angular error of less than . We lastly illustrate the 2D velocity field reconstructed from in-vivo Color-Doppler data. Observing the hemodynamics in patients is expected to have a clinical impact in assessing disease development and progression, such as abdominal aortic aneurysms.
Latest publication in MeDiTATe project. EndoBeams.jl: A Julia finite element package for beam-to-surface contact problems in cardiovascular mechanics

Beatrice Bisighini, ESR 03 in the MeDiTATe project, published the paper titled EndoBeams.jl: A Julia finite element package for beam-to-surface contact problems in cardiovascular mechanics on Advances in Engineering Software journal.
The work was developed in collaboration with Miquel Aguirre, Baptiste Pierrat and Stéphane Avril from Mines Saint-Étienne and David Perrin from PrediSurge.
The paper, whose abstract is reported in the following lines, is available at this link.
The increasing use of mini-invasive and endovascular surgical techniques is at the origin of the pressing need for
computational models to support planning and training. Several implantable devices have a wire-like structure,
which can be modelled using beam elements. Our objective is to create an efficient Finite Element (FE) modelling
framework for such devices. For that, we developed the EndoBeams.jl package, written exclusively in Julia, for
the numerical simulation of contact interactions between wire-like structures and rigid surfaces. The package is
based on a 3D FE corotational formulation for frictional contact dynamics of beams. The rigid target surface is
described implicitly using a signed distance field, predefined in a volumetric grid. Since the main objective
behind this package is to find the best compromise between computational speed and code readability, the al-
gorithm, originally in Matlab, was translated and optimised in Julia, a programming language designed to
combine the performance of low-level languages with the productivity of high-level ones. To evaluate the
robustness, a set of tests were conducted to compare the simulation results and computational time of Endo-
Beams.jl against literature data, the original Matlab code and the commercial software Abaqus. The tests proved
the accuracy of the underlying beam-to-surface formulation and showed the drastic performance improvement of
the Julia code with respect to the original one. EndoBeams.jl is also slightly faster than Abaqus. Finally, as a proof
of concept in cardiovascular medicine, a further example is shown where the deployment of a braided stent is
simulated within an idealised artery.
MeDiTATe project new publication. The Hemodynamic Effect of Modified Blalock–Taussig Shunt Morphologies: A Computational Analysis Based on Reduced Order Modeling

Eirini Kardampiki, ESR 12 in the MeDiTATe project, published the paper titled The Hemodynamic Effect of Modified Blalock–Taussig Shunt Morphologies: A Computational Analysis Based on Reduced Order Modeling on Electronics Journal from MDPI.
The work was developed in collaboration with Emanuele Vignali and Simona Celi from BioCardioLab (Fondazione Toscana G. Monasterio), Dorela Haxhiademi from Critical Care Unit (Fondazione Toscana G. Monasterio), Duccio Federici from Paediatric Cardiosurgery Unit (Fondazione Toscana G. Monasterio). A further contribution was given by Edoardo Ferrante, Margherita Cioffi and Emiliano Costa from RINA, Stefano Porziani and Andrea Chiappa from RBF Morph, Corrado Groth and Marco Evangelos Biancolini from the Department of Enterprise Engineering (University of Rome Tor Vergata).
The paper, whose abstract is reported in the following lines, is available at this link.
The Modified Blalock Taussig Shunt (MBTS) is one of the most common palliative operations in case of cyanotic heart diseases. Thus far, the decision on the position, size, and geometry of the implant relies on clinicians’ experience. In this paper, a Medical Digital Twin pipeline based on reduced order modeling is presented for fast and interactive evaluation of the hemodynamic parameters of MBTS. An infant case affected by complete pulmonary atresia was selected for this study. A three-dimensional digital model of the infant’s MBTS morphology was generated. A wide spectrum of MBTS geometries was explored by introducing twelve Radial Basis Function mesh modifiers. The combination of these modifiers allowed for analysis of various MBTS shapes. The final results proved the potential of the proposed approach for the investigation of significant hemodynamic features such as velocity, pressure, and wall shear stress as a function of the shunt’s morphology in real-time. In particular, it was demonstrated that the modifications of the MBTS morphology had a profound effect on the hemodynamic indices. The adoption of reduced models turned out to be a promising path to follow for MBTS numerical evaluation, with the potential to support patient-specific preoperative planning.
First MeDiTATe project publication. High fidelity fluid-structure interaction by radial basis functions mesh adaption of moving walls: a workflow applied to an aortic valve

Leonardo Geronzi, Early Stage Researcher 02 in the MeDiTATe project, published the paper titled High fidelity fluid-structure interaction by radial basis functions mesh adaption of moving walls: a workflow applied to an aortic valve in the Journal of Computational Science.
This work was developed in collaboration with Emanuele Gasparotti, Katia Cappellini and Simona Celi from BioCardioLab (Bioengineering Unit, Fondazione Toscana “G. Monasterio”, Heart Hospital, Massa, Italy), and Ubaldo Cella, Corrado Groth, Stefano Porziani and Marco Evangelos Biancolini from the Department of Enterprise Engineering “Mario Lucertini” (University of Rome Tor Vergata, Roma, Italy).
The open access full text is available here, while the article abstract is reported below.
Fluid-Structure Interaction (FSI) can be investigated by means of non-linear Finite Element Models (FEM), suitable to capture large deflections of structural parts interacting with fluids, and Computational Fluid Dynamics (CFD). High fidelity simulations are obtained using the fine spatial resolution of both the structural and fluid computational grids. A key enabler to have a proper exchange of information between the structural solver and the fluid one is the management of the interface at wetted surfaces where the grids are usually non-matching. A class of applications, known also as one-way FSI problems, involves a complex movement of the walls that is known in advance as measured or as computed by FEM, and that has to be imposed at the boundaries during a transient CFD solution. Effective methods for the time marching adaption of the whole computational grid of the CFD model according to the evolving shape of its boundaries are required. A very well established approach consists of a continuum update of the mesh that is regenerated by adding and removing cells to fit the evolution of the moving walls. In this paper, an innovative method based on Radial Basis Functions (RBF) mesh morphing is proposed, allowing the retention of the same mesh topology suitable for a continuum update of the shape. The proposed method is exact at a set of given key configurations and relies on shape blending time interpolation between key frames. The study of the complex motion of a Polymeric-Prosthetic Heart Valve (P-PHV) is presented using the new framework and considering as a reference the established approach based on remeshing.
An interview with Dr. Ubaldo Cella, Project Manager of the MeDiTATe project

Here is an interview with Dr. Ubaldo Cella, researcher at the University of Rome Tor Vergata and Project Manager of the MeDiTATe project.
The MeDiTATe project is one of the largest Industrial Doctorate Programmes funded by the EU Commission. As Project Manager, what are the key points to keep in mind when dealing with the management of such a large Consortium?
One determining factor is having the support of a team specialized in covering all the aspects that a project like MeDiTATe involves. Our consortium is composed of 12 beneficiaries and 13 partners from eight countries, including Australia. It is a broad Consortium that involves institutions with different backgrounds (academic, industrial, manufacturing, medical) and heterogeneous dynamics both in the administrative procedures and in the scientific focus. The complexities of interacting with so many subjects, and of fulfilling the several requirements that a mobility-based project requires, is clearly a demanding task. Furthermore, the large number of Individual Research Projects, in which 14 Early-Stage Researchers are enrolled, involves a heavy administrative burden. The University of Rome “Tor Vergata” has significant experience in managing all the aspects of big projects such as this one. The coordination of MeDiTATe is based on a structured organization in which a large competent staff from offices focused on international research, privacy policy, recruitment, and legal aspects support the PI and the PM in solving all tasks of the project management. Furthermore, the day-to-day coordination is shared with four partners and members of the steering committee, who are responsible for recruitment, training, communication, scientific dissemination, and ethics protocols. Another crucial factor is the very productive communication channel created by the EU Project Officer. In the last two years we had several complex situations to manage. His support was decisive and always promptly available.
The entire project is based on the collaboration within the members of private and public companies, hospitals and research institutions and universities. How can the Project Manager facilitate the cooperation and the communication amongst these different realities?
The MeDiTATe project is an extraordinary environment in which scientists with very different backgrounds in different disciplines share their competences to pursue a common objective. This is not common in the research world and represents one of the added values of our project. We are doing our best to create a network, organize meetings, develop connections and to stimulate collaboration between the fellows. All the Supervisors are invited to identify common interests and propose further research, expanding the connection to projects other than MeDiTATe. Unfortunately, the pandemic situation has created many obstacles most notably the importance of human contact. To remedy this, we have utilized digital platforms to facilitate the communication but inevitably many opportunities have been lost. Read More
The MeDiTATe project at the 9th World Congress of Biomechanics 2022 (WCB 2022)





The MeDiTATe project will be participating in the 9th World Congress of Biomechanics (WCB 2022). The event will be held from 10th to 14th July 2022 at the Taipei International Convention Center (TICC) in Taipei. Four of our Early Stage Researchers will be presenting their work as shown in the following sections.
ESR 09, Martino Andrea Scarpolini: A comparative study between CFD, FSI and radial basis functions mesh morphing technique based on biomedical images for aortic hemodynamic studies. Computational fluid dynamics (CFD) and fluid structure interaction (FSI) simulations are effective tools used in the literature to study aortic hemodynamics. Nevertheless, these numerical approaches are characterised by some limitations, such as the assumption of a rigid wall for CFD and assumptions on material properties together with high computational times for FSI simulations. Knowledge of the actual material properties of the aortic tissue is crucial for the analysis of different pathologies. In this work we present a new in-vivo method based on biomedical images and the RBF mesh morphing technique to estimate the stiffness of the aorta. A comparison of hemodynamic outcomes between different simulation strategies is shown: CFD, CFD with prescribed wall movement (from CT scans) and two way FSI with the estimated elastic module.
ESR 10, Francesco Bardi: Mechanics and fluid dynamics characterization of a compliant patient specific aortic phantom in a Hybrid Mock Circulatory Loop. Mock Circulatory Loops MCLs are commonly used for in-vitro testing of medical devices, anatomical models, and diagnostic imaging tools. However standard MCLs cannot reproduce complex systems with high accuracy and repeatability, as the uncertainty associated with the calibration of the setup and the parasitic effects become non-negleagible. A Hybrid Mock Circulatory Loop (HMCL) is a Hardware-in-The-Loop system that is used to characterize cardiovascular systems. A numerical-hydraulic interface couples the physical components with a software simulated environment. In this work we show how an HMCL can be effectively used to characterize the fluid dynamic and the mechanical response of a compliant aortic model. Moreover, the obtained experimental data are compared with the results of a Fluid Structure Interaction (FSI) simulation.
ESR 12, Eirini Kardampiki: From CTA to Personalized Reduced Order Model for Modified Blalock Taussig Shunt patients. In this work, a Medical Digital Twin pipeline, based on reduced order modeling, for the fast and interactive evaluation of the hemodynamic parameters for MBTS is presented. Starting from the generation of a 3D digital model of an infant case affected by complete pulmonary atresia, a wide spectrum of MBTS geometries was explored by introducing twelve Radial Basis Functions mesh modifiers. The combination of these modifiers allowed the analysis of various MBTS shapes. Eventually, a ROM was built based on high-fidelity CFD data for the prediction of significant hemodynamic features such as velocity, pressure and wall shear stress in function of the shunt’s morphology in real-time.
ESR 14, Maria Nicole Antonuccio: Color-Doppler ultrasound-based hemodynamics of abdominal aortic aneurysm. 2D Color-Doppler ultrasound (US) imaging can partially capture flow information. Biomechanics principles can augment the missing flow information given by 2D Color-Doppler to quantify AAA hemodynamics for better AAA rupture risk prediction. Examples of hemodynamic characterization, based on the reconstruction of the velocity vector field in a AAA using Color-Doppler images, are presented in the study with the final aim of complementing the AAA diagnosis and supporting therapy planning and optimization.