Three-Dimensional Imaging Defines Straddling Mitral Valve Anatomy to Allow Successful Biventricular Repair.

Biventricular repair of a straddling mitral valve (MV) can involve relocating ectopic papillary muscles and chordae. However, this increases operative complexity and risks MV incompetence. We describe a nine-month-old with D-transposition of the great arteries and straddling MV.

Simulating cardiac fluid dynamics in the human heart.

Cardiac fluid dynamics fundamentally involves interactions between complex blood flows and the structural deformations of the muscular heart walls and the thin valve leaflets. There has been longstanding scientific, engineering, and medical interest in creating mathematical models of the heart that capture, explain, and predict these fluid-structure interactions (FSIs). However, existing computational models that account for interactions among the blood, the actively contracting myocardium, and the valves are limited in their abilities to predict valve performance, capture fine-scale flow features, or use realistic descriptions of tissue biomechanics.

Demographics, Utilization, Workflow, and Outcomes Based on Observational Data From the RSNA-ACR 3D Printing Registry.

Purpose: The aim of this study was to report data from the first 3 years of operation of the RSNA-ACR 3D Printing Registry.

Methods: Data from June 2020 to June 2023 were extracted, including demographics, indications, workflow, and user assessments. Clinical indications were stratified by 12 organ systems.

Ultrasound Visualization and Recording of Transient Myocardial Vibrations.

Objective: A new visualization and recording method used to assess and quantitate autogenic high-velocity motions in myocardial walls to provide a new description of cardiac function is described.

Methods: The regional motion display (RMD) is based on high-speed difference ultrasound B-mode images and spatiotemporal processing to record propagating events (PEs). Sixteen normal participants and one patient with cardiac amyloidosis were imaged at rates of 500-1000/s using the Duke Phased Array Scanner, T5.

Whole-Chest Three-Dimensional Modeling Aids Hybrid Pulmonary Valve Replacement Following Double Switch Operation.

The double switch operation for congenitally corrected transposition of the great arteries (CC-TGA) has been associated with high rates of reintervention, including the need for pulmonary valve replacement. Hybrid interventional approaches can avoid bypass when complex anatomy complicates traditional catheter-based approaches. We present a case of successful transcatheter pulmonary valve replacement via hybrid per-ventricular approach with pre-procedural planning aided by 3D segmentation of skeletal and cardiac anatomy in a patient with surgically corrected CC-GTA.

Three-dimensional modeling of the mitral valve for surgical planning in a pediatric patient: A case-based discussion of the technical challenges of segmentation and printing from 3D transthoracic echocardiographic datasets.

Abnormal atrioventricular valve present great challenges to the surgeon in achieving a successful repair, and thus present a great opportunity for enhanced 3D imaging to guide pre- and intra-operative management. Spatial and temporal resolution of 3D echocardiography enables 3D printing of valve morphology. However, non-linearity, angle dependence, speckle, blur, and resampling complicate segmentation compared to computed tomography (CT) and magnetic resonance imaging (MRI).

Impact of Using Uniform Attenuation Coefficients for Heterogeneously Dense Breasts in a Dedicated Breast PET/X-ray Scanner.

We investigated PET image quantification when using a uniform attenuation coefficient () for attenuation correction (AC) of anthropomorphic density phantoms derived from high-resolution breast CT scans. A breast PET system was modeled with perfect data corrections except for AC. Using uniform for AC resulted in quantitative errors roughly proportional to the difference between used in AC ( ) and local , yielding approximately ± 5% bias, corresponding to the variation of for 511 keV photons in breast tissue.

Preprocedural three-dimensional planning aids in transcatheter ductal stent placement: A single-center experience.

Objectives: Describe the use of three-dimensional (3D) patent ductus arteriosus (PDA) modeling to better define ductal anatomy to improve preprocedural planning for ductal stent placement.

Background: Ductal stenting is an alternative to surgical shunting in patients with ductal dependent pulmonary blood flow. Ductal anatomy is often complex with extreme tortuosity and risk of pulmonary artery isolation, thus increasing procedural risks.

Modeling "Textured" Bones in Virtual Human Phantoms.

The purpose of this study was to develop detailed and realistic models of the cortical and trabecular bones in the spine, ribs, and sternum and incorporate them into the library of virtual human phantoms (XCAT). Cortical bone was modeled by 3D morphological erosion of XCAT homogenously defined bones with an average thickness measured from the CT dataset upon which each individual XCAT phantom was based. The trabecular texture was modeled using a power law synthesis algorithm where the parameters were tuned using high-resolution anatomical images of the Human Visible Female.

Incorporation of the Living Heart Model into the 4D XCAT Phantom for Cardiac Imaging Research.

The 4D extended cardiac-torso (XCAT) phantom has provided a valuable tool to study the effects of anatomy and motion on medical images, especially cardiac motion. One limitation of the XCAT was that it did not have a physiological basis which to realistically simulate variations in cardiac function. In this work, we incorporate into the XCAT anatomy the four-chamber FE Living Heart Model (LHM) developed by the Living Heart Project (LHP).

Modeling Lung Architecture in the XCAT Series of Phantoms: Physiologically Based Airways, Arteries and Veins.

The purpose of this paper was to extend the extended cardiac-torso (XCAT) series of computational phantoms to include a detailed lung architecture including airways and pulmonary vasculature. Eleven XCAT phantoms of varying anatomy were used in this paper. The lung lobes and initial branches of the airways, pulmonary arteries, and veins were previously defined in each XCAT model.

Quantification of uncertainty in the assessment of coronary plaque in CCTA through a dynamic cardiac phantom and 3D-printed plaque model.

The purpose of this study was to develop a dynamic physical cardiac phantom with a realistic coronary plaque to investigate stenosis measurement accuracy under clinically relevant heart-rates. The coronary plaque model (5 mm diameter, 50% stenosis, and 32 mm long) was designed and 3D-printed with tissue equivalent materials (calcified plaque with iodine-enhanced lumen). Realistic cardiac motion was modeled by converting computational cardiac motion vectors into compression and rotation profiles executed by a commercial base cardiac phantom.

Synthetic breast phantoms from patient based eigenbreasts.

Purpose: The limited number of 3D patient-based breast phantoms available could be augmented by synthetic breast phantoms in order to facilitate virtual clinical trials (VCTs) using model observers for breast imaging optimization and evaluation.

Methods: These synthetic breast phantoms were developed using Principal Component Analysis (PCA) to reduce the number of dimensions needed to describe a training set of images. PCA decomposed a training set of M breast CT volumes (with millions of voxels each) into an M-1-dimensional space of eigenvectors, which we call eigenbreasts.

Breast dose reduction with organ-based, wide-angle tube current modulated CT.

This study aimed to estimate the organ dose reduction potential for organ-dose-based tube current modulated (ODM) thoracic computed tomography (CT) with a wide dose reduction arc. Twenty-one computational anthropomorphic phantoms (XCAT) were used to create a virtual patient population with clinical anatomic variations. The phantoms were created based on patient images with normal anatomy (age range: 27 to 66 years, weight range: 52.

CT breast dose reduction with the use of breast positioning and organ-based tube current modulation.

Purpose: This study aimed to investigate the breast dose reduction potential of a breast-positioning (BP) technique for thoracic CT examinations with organ-based tube current modulation (OTCM).

Methods: This study included 13 female anthropomorphic computational phantoms (XCAT, age range: 27-65 y.o.

Biomechanics Simulations Using Cubic Hermite Meshes with Extraordinary Nodes for Isogeometric Cardiac Modeling.

Cubic Hermite hexahedral finite element meshes have some well-known advantages over linear tetrahedral finite element meshes in biomechanical and anatomic modeling using isogeometric analysis. These include faster convergence rates as well as the ability to easily model rule-based anatomic features such as cardiac fiber directions. However, it is not possible to create closed complex objects with only regular nodes; these objects require the presence of extraordinary nodes (nodes with 3 or >= 5 adjacent elements in 2D) in the mesh.

Finite-element modeling of compression and gravity on a population of breast phantoms for multimodality imaging simulation.

Purpose: The authors are developing a series of computational breast phantoms based on breast CT data for imaging research. In this work, the authors develop a program that will allow a user to alter the phantoms to simulate the effect of gravity and compression of the breast (craniocaudal or mediolateral oblique) making the phantoms applicable to multimodality imaging.

Methods: This application utilizes a template finite-element (FE) breast model that can be applied to their presegmented voxelized breast phantoms.

Population of 224 realistic human subject-based computational breast phantoms.

Purpose: To create a database of highly realistic and anatomically variable 3D virtual breast phantoms based on dedicated breast computed tomography (bCT) data.

Methods: A tissue classification and segmentation algorithm was used to create realistic and detailed 3D computational breast phantoms based on 230 + dedicated bCT datasets from normal human subjects. The breast volume was identified using a coarse three-class fuzzy C-means segmentation algorithm which accounted for and removed motion blur at the breast periphery.

The development of a population of 4D pediatric XCAT phantoms for imaging research and optimization.

Purpose: We previously developed a set of highly detailed 4D reference pediatric extended cardiac-torso (XCAT) phantoms at ages of newborn, 1, 5, 10, and 15 yr with organ and tissue masses matched to ICRP Publication 89 values. In this work, we extended this reference set to a series of 64 pediatric phantoms of varying age and height and body mass percentiles representative of the public at large. The models will provide a library of pediatric phantoms for optimizing pediatric imaging protocols.

Development of realistic physical breast phantoms matched to virtual breast phantoms based on human subject data.

Purpose: Physical phantoms are essential for the development, optimization, and evaluation of x-ray breast imaging systems. Recognizing the major effect of anatomy on image quality and clinical performance, such phantoms should ideally reflect the three-dimensional structure of the human breast. Currently, there is no commercially available three-dimensional physical breast phantom that is anthropomorphic.

A set of 4D pediatric XCAT reference phantoms for multimodality research.

Purpose: The authors previously developed an adult population of 4D extended cardiac-torso (XCAT) phantoms for multimodality imaging research. In this work, the authors develop a reference set of 4D pediatric XCAT phantoms consisting of male and female anatomies at ages of newborn, 1, 5, 10, and 15 years. These models will serve as the foundation from which the authors will create a vast population of pediatric phantoms for optimizing pediatric CT imaging protocols.

A three-dimensional finite element model of human atrial anatomy: new methods for cubic Hermite meshes with extraordinary vertices.

High-order cubic Hermite finite elements have been valuable in modeling cardiac geometry, fiber orientations, biomechanics, and electrophysiology, but their use in solving three-dimensional problems has been limited to ventricular models with simple topologies. Here, we utilized a subdivision surface scheme and derived a generalization of the "local-to-global" derivative mapping scheme of cubic Hermite finite elements to construct bicubic and tricubic Hermite models of the human atria with extraordinary vertices from computed tomography images of a patient with atrial fibrillation. To an accuracy of 0.