A clinically applicable strategy to estimate the in vivo distribution of mechanical material properties of the right ventricular wall.

A clinically applicable approach to estimate the in vivo mechanical material properties of the heart wall is presented. This optimization-based inverse estimation approach applies a shape-based objective functional combined with rigid body registration and incremental parameterization of heterogeneity to use standard clinical imaging data along with simplified representations of cardiac function to provide consistent and physically meaningful solution estimates. The capability of the inverse estimation algorithm is evaluated through application to two clinically obtained human datasets to estimate the passive elastic mechanical properties of the heart wall, with an emphasis on the right ventricle.

Right Ventricular Shape Feature Quantification for Evaluation of Pulmonary Hypertension: Feasibility and Preliminary Associations With Clinical Outcome Submitted for Publication.

This study aimed to demonstrate feasibility of statistical shape analysis techniques to identify distinguishing features of right ventricle (RV) shape as related to hemodynamic variables and outcome data in pulmonary hypertension (PH). Cardiovascular magnetic resonance images were acquired from 50 patients (33 PH, 17 non-PH). Contemporaneous right heart catheterization data were collected for all individuals.

Effect of opaque wraps for pulse oximeter sensors: randomised cross-over trial.

Background: Evidence is lacking as to whether ambient light or phototherapy light could interfere with pulse oximeter performance.

Methods: In this randomised cross-over trial, we recruited neonates of gestation >24 weeks. Consented infants were randomly assigned to either pulse oximeter sensor with opaque wrap or without opaque wrap.

Predicting responses to mechanical ventilation for preterm infants with acute respiratory illness using artificial neural networks.

Infants born prematurely are particularly susceptible to respiratory illness due to underdeveloped lungs, which can often result in fatality. Preterm infants in acute stages of respiratory illness typically require mechanical ventilation assistance, and the efficacy of the type of mechanical ventilation and its delivery has been the subject of a number clinical studies. With recent advances in machine learning approaches, particularly deep learning, it may be possible to estimate future responses to mechanical ventilation in real time, based on ventilation monitoring up to the point of analysis.

Mapped Chebyshev pseudo-spectral method for simulating the shear wave propagation in the plane of symmetry of a transversely isotropic viscoelastic medium.

Shear wave elastography is a versatile technique that is being applied to many organs. However, in tissues that exhibit anisotropic material properties, special care must be taken to estimate shear wave propagation accurately and efficiently. A two-dimensional simulation method is implemented to simulate the shear wave propagation in the plane of symmetry in transversely isotropic viscoelastic media.

Modeling transversely isotropic, viscoelastic, incompressible tissue-like materials with application in ultrasound shear wave elastography.

In this paper, we propose a method to model the shear wave propagation in transversely isotropic, viscoelastic and incompressible media. The targeted application is ultrasound-based shear wave elastography for viscoelasticity measurements in anisotropic tissues such as the kidney and skeletal muscles. The proposed model predicts that if the viscoelastic parameters both across and along fiber directions can be characterized as a Voigt material, then the spatial phase velocity at any angle is also governed by a Voigt material model.

Non-invasive assessment of elastic modulus of arterial constructs during cell culture using ultrasound elasticity imaging.

Mechanical strength is a key design factor in tissue engineering of arteries. Most existing techniques assess the mechanical property of arterial constructs destructively, leading to sacrifice of a large number of animals. We propose an ultrasound-based non-invasive technique for the assessment of the mechanical strength of engineered arterial constructs.

A new approach to kinematic feature extraction from the human right ventricle for classification of hypertension: a feasibility study.

This work presents a novel approach to analyze the function of the human right ventricle (RV) by deriving kinematic features of the relative change in shape throughout the cardiac cycle. The approach is anatomically consistent, allows direct comparison across populations of individuals, and potentially provides new metrics to improve the diagnosis and understanding of cardiovascular diseases such as pulmonary hypertension (PH). The details of the approach are presented, which includes a variation of harmonic topological mapping and proper orthogonal decomposition techniques, with particular focus on their applicability with respect to untagged cardiac imaging data.

An inverse problem approach for elasticity imaging through vibroacoustics.

A methodology for estimating the spatial distribution of elastic moduli using the steady-state dynamic response of solids immersed in fluids is presented. The technique relies on the ensuing acoustic field from a remotely excited solid to inversely estimate the spatial distribution of Young's modulus of biological structures (e.g.

Identification of material properties of orthotropic elastic cylinders immersed in fluid using vibroacoustic techniques.

A numerical study is presented to show the potential for using vibroacoustic-based experiments to identify elastic material properties of orthotropic cylindrical vessels immersed in fluids. Sensitivity analyses and a simulated inverse problem are shown to quantify the potential for material characterization through the use of acoustic emissions. For comparison purposes, the analyses are also shown with the normal component of the velocity at the surface of the cylinder as the measured response in place of the acoustic pressure.

When does quality count?: Perceptions of hearsay testimony about child sexual abuse interviews.

This study assessed how the quality of a sexual abuse investigative interview with a child and the age of the child influence jurors' reactions to either the original interview with the child or to testimony by an adult hearsay witness (the interviewer). Participants (N = 360) were randomly assigned to 1 of 12 conditions in a 2 (type of testimony: hearsay testimony vs. child interview) x 3 (interview quality: poor, typical, or good) x 2 (age of the child: 4 years old vs.