Purpose: To propose and assess a new method that automatically extracts a three-dimensional (3D) geometric model of the thoracic aorta (TA) from 3D cine phase contrast MRI (PCMRI) acquisitions.
Methods: The proposed method is composed of two steps: segmentation of the TA and creation of the 3D geometric model. The segmentation algorithm, based on Level Set, was set and applied to healthy subjects acquired in three different modalities (with and without SENSE reduction factors). Accuracy was evaluated using standard quality indices. The 3D model is characterized by the vessel surface mesh and its centerline; the comparison of models obtained from the three different datasets was also carried out in terms of radius of curvature (RC) and average tortuosity (AT).
Results: In all datasets, the segmentation quality indices confirmed very good agreement between manual and automatic contours (average symmetric distance < 1.44 mm, DICE Similarity Coefficient > 0.88). The 3D models extracted from the three datasets were found to be comparable, with differences of less than 10% for RC and 11% for AT.
Conclusion: Our method was found effective on PCMRI data to provide a 3D geometric model of the TA, to support morphometric and hemodynamic characterization of the aorta.
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http://dx.doi.org/10.1002/mrm.25630 | DOI Listing |
J Nonlinear Sci
January 2025
Robotics and Mechatronics Department, University of Twente, Enschede, The Netherlands.
In this paper, we present a novel approach to the geometric formulation of solid and fluid mechanics within the port-Hamiltonian framework, which extends the standard Hamiltonian formulation to non-conservative and open dynamical systems. Leveraging Dirac structures, instead of symplectic or Poisson structures, this formalism allows the incorporation of energy exchange within the spatial domain or through its boundary, which allows for a more comprehensive description of continuum mechanics. Building upon our recent work in describing nonlinear elasticity using exterior calculus and bundle-valued differential forms, this paper focuses on the systematic derivation of port-Hamiltonian models for solid and fluid mechanics in the material, spatial, and convective representations using Hamiltonian reduction theory.
View Article and Find Full Text PDFJ Nucl Med
January 2025
Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York.
Accurate quantification in emission tomography is essential for internal radiopharmaceutical therapy dosimetry. Mean activity concentration measurements in objects with diameters less than 10 times the full width at half maximum of the imaging system's spatial resolution are significantly affected (>10%) by the partial-volume effect. This study develops a framework for PET and SPECT spatial resolution characterization and proposes 2 MIRD recovery coefficient models-a geometric mean approximation (RECOVER-GM) and an empirical model (RECOVER-EM)-that provide shape-specific partial-volume correction (PVC).
View Article and Find Full Text PDFMed Image Anal
January 2025
Department of Mechanical and Metallurgical Engineering, School of Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile; Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile; Millennium Institute for Intelligent Healthcare Engineering, iHEALTH, Chile. Electronic address:
The identification of the Purkinje conduction system in the heart is a challenging task, yet essential for a correct definition of cardiac digital twins for precision cardiology. Here, we propose a probabilistic approach for identifying the Purkinje network from non-invasive clinical data such as the standard electrocardiogram (ECG). We use cardiac imaging to build an anatomically accurate model of the ventricles; we algorithmically generate a rule-based Purkinje network tailored to the anatomy; we simulate physiological electrocardiograms with a fast model; we identify the geometrical and electrical parameters of the Purkinje-ECG model with Bayesian optimization and approximate Bayesian computation.
View Article and Find Full Text PDFEur Heart J Cardiovasc Imaging
January 2025
PULS/e group, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
Aims: Image-based, patient-specific rupture risk analysis of AAAs is promising but it is limited by invasive and costly imaging modalities. Ultrasound (US) offers a safe, more affordable alternative, allowing multiple assessments during follow-up and enabling longitudinal studies on AAA rupture risk.
Methods And Results: This study used time-resolved three-dimensional US to assess AAA rupture risk parameters over time, based on vessel and intraluminal thrombus (ILT) geometry.
Eco Environ Health
March 2025
College of Natural Resources and Environment, Northwest A & F University, Xianyang 712100, China.
The interactions of nanoplastics (NPs) with natural organic matters (NOMs) dominate the environmental fate of both substances and the organic carbon cycle. Their binding and aggregation mechanisms at the molecular level remain elusive due to the high structural complexity of NOMs and aged NPs. Molecular modeling was used to understand the detailed dynamic interaction mechanism between NOMs and NPs.
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