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result(s) for
"Toussaint, Nicolas"
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Virtual interaction and visualisation of 3D medical imaging data with VTK and Unity
by
Schnabel, Julia A
,
Wheeler, Gavin
,
Toussaint, Nicolas
in
3-D graphics
,
3D medical imaging data
,
augmented reality
2018
The authors present a method to interconnect the Visualisation Toolkit (VTK) and Unity. This integration enables them to exploit the visualisation capabilities of VTK with Unity's widespread support of virtual, augmented, and mixed reality displays, and interaction and manipulation devices, for the development of medical image applications for virtual environments. The proposed method utilises OpenGL context sharing between Unity and VTK to render VTK objects into the Unity scene via a Unity native plugin. The proposed method is demonstrated in a simple Unity application that performs VTK volume rendering to display thoracic computed tomography and cardiac magnetic resonance images. Quantitative measurements of the achieved frame rates show that this approach provides over 90 fps using standard hardware, which is suitable for current augmented reality/virtual reality display devices.
Journal Article
Measuring cortical mean diffusivity to assess early microstructural cortical change in presymptomatic familial Alzheimer’s disease
by
Simpson, Ivor J. A.
,
Zhang, Hui
,
Ryan, Natalie S.
in
Advertising executives
,
Alzheimer Disease - diagnostic imaging
,
Alzheimer Disease - genetics
2020
Background
There is increasing interest in improving understanding of the timing and nature of early neurodegeneration in Alzheimer’s disease (AD) and developing methods to measure this in vivo. Autosomal dominant familial Alzheimer’s disease (FAD) provides the opportunity for investigation of presymptomatic change. We assessed early microstructural breakdown of cortical grey matter in FAD with diffusion-weighted MRI.
Methods
Diffusion-weighted and T1-weighed MRI were acquired in 38 FAD mutation carriers (17 symptomatic, 21 presymptomatic) and 39 controls. Mean diffusivity (MD) was calculated for six cortical regions previously identified as being particularly vulnerable to FAD-related neurodegeneration. Linear regression compared MD between symptomatic and presymptomatic carriers and controls, adjusting for age and sex. Spearman coefficients assessed associations between cortical MD and cortical thickness. Spearman coefficients also assessed associations between cortical MD and estimated years to/from onset (EYO). Across mutation carriers, linear regression assessed associations between MD and EYO, adjusting for cortical thickness.
Results
Compared with controls, cortical MD was higher in symptomatic mutation carriers (mean ± SD CDR = 0.88 ± 0.39) for all six regions (
p
< 0.001). In late presymptomatic carriers (within 8.1 years of predicted symptom onset), MD was higher in the precuneus (
p
= 0.04) and inferior parietal cortex (
p
= 0.003) compared with controls. Across all presymptomatic carriers, MD in the precuneus correlated with EYO (
p
= 0.04). Across all mutation carriers, there was strong evidence (
p
< 0.001) of association between MD and cortical thickness in all regions except entorhinal cortex. After adjusting for cortical thickness, there remained an association (
p
< 0.05) in mutation carriers between MD and EYO in all regions except entorhinal cortex.
Conclusions
Cortical MD measurement detects microstructural breakdown in presymptomatic FAD and correlates with proximity to symptom onset independently of cortical thickness. Cortical MD may thus be a feasible biomarker of early AD-related neurodegeneration, offering additional/complementary information to conventional MRI measures.
Journal Article
NiftyFit: a Software Package for Multi-parametric Model-Fitting of 4D Magnetic Resonance Imaging Data
by
Melbourne, Andrew
,
Atkinson, David
,
Toussaint, Nicolas
in
Bioinformatics
,
Biomedical and Life Sciences
,
Biomedicine
2016
Multi-modal, multi-parametric Magnetic Resonance (MR) Imaging is becoming an increasingly sophisticated tool for neuroimaging. The relationships between parameters estimated from different individual MR modalities have the potential to transform our understanding of brain function, structure, development and disease. This article describes a new software package for such multi-contrast Magnetic Resonance Imaging that provides a unified model-fitting framework. We describe model-fitting functionality for Arterial Spin Labeled MRI, T1 Relaxometry, T2 relaxometry and Diffusion Weighted imaging, providing command line documentation to generate the figures in the manuscript. Software and data (using the nifti file format) used in this article are simultaneously provided for download
.
We also present some extended applications of the joint model fitting framework applied to diffusion weighted imaging and T2 relaxometry, in order to both improve parameter estimation in these models and generate new parameters that link different MR modalities.
NiftyFit
is intended as a clear and open-source educational release so that the user may adapt and develop their own functionality as they require.
Journal Article
A Virtual Reality System for Improved Image-Based Planning of Complex Cardiac Procedures
by
Lin, Ei
,
Bhattacharya, Suryava
,
Schnabel, Julia A.
in
Augmented reality
,
Collaboration
,
Communication
2021
The intricate nature of congenital heart disease requires understanding of the complex, patient-specific three-dimensional dynamic anatomy of the heart, from imaging data such as three-dimensional echocardiography for successful outcomes from surgical and interventional procedures. Conventional clinical systems use flat screens, and therefore, display remains two-dimensional, which undermines the full understanding of the three-dimensional dynamic data. Additionally, the control of three-dimensional visualisation with two-dimensional tools is often difficult, so used only by imaging specialists. In this paper, we describe a virtual reality system for immersive surgery planning using dynamic three-dimensional echocardiography, which enables fast prototyping for visualisation such as volume rendering, multiplanar reformatting, flow visualisation and advanced interaction such as three-dimensional cropping, windowing, measurement, haptic feedback, automatic image orientation and multiuser interactions. The available features were evaluated by imaging and nonimaging clinicians, showing that the virtual reality system can help improve the understanding and communication of three-dimensional echocardiography imaging and potentially benefit congenital heart disease treatment.
Journal Article
Staff Education to Address Medication Noncompliance in Outpatient Behavioral Health Settings
2026
This quality improvement project is a staff education initiative designed to address psychotropic medication noncompliance in an outpatient behavioral health clinic setting. The project arose from the identification of a significant gap in staff knowledge and confidence related to medication adherence strategies. Medication noncompliance in psychiatric care is associated with symptom exacerbation, increased hospitalization, and poorer patient outcomes, making it a critical issue in nursing practice. The practice-focused question guiding the project was: In an outpatient behavioral health clinic setting, does implementing a structured staff education program improve staff knowledge and confidence in addressing medication noncompliance? Analytical strategies included a review and synthesis of research and nonresearch evidence using validated appraisal tools. I collected evidence from 10 scholarly sources. A stakeholder analysis; strengths, weaknesses, opportunities, and threats analysis; and translation planning tool supported the project’s alignment and feasibility. Participants’ pretest scores averaged 48%, while their posttest scores rose to an average of 85.2%, reflecting a normalized learning gain of 77%. Staff reported higher confidence in applying motivational interviewing techniques, culturally responsive care, and adherence support strategies following the education program. Key products included a staff education checklist, instructional materials, and an evaluation plan. The project holds important implications for nursing practice by empowering staff to apply evidence-based strategies in medication adherence counseling. The project supports positive social change by improving mental health outcomes among underserved populations and aligning with culturally tailored content and a patient-centered framework.
Dissertation
Non-selective double inversion recovery pre-pulse for flow-independent black blood myocardial viability imaging
2010
Doc number: P104
Journal Article
Curvilinear analysis and approximation of cardiac dti in-vivo
2013
Diffusion Tensor MRI can be used to depict the anisotropy of tissue. Translation of this technique to moving objects such as the beating heart has recently become feasible, but remains a challenging task, often leading to high noise levels and limited accuracy. Ultimately, knowledge of the 3D fibre architecture of the myocardium in vivo should allow for a better understanding of the cardiac function both in healthy and pathological situations. The main goal of the work presented in this thesis is to overcome the difficulties that such technology presents, by introducing a combination of image process ing and analysis approaches. In particular, the characteristic ellipsoidal shape of the left ventricular chamber is used to introduce a shape-based prolate spheroidal coordinate frame that allows for comprehensive, robust and dedicated analysis of diffusion tensor data within the myocardial wall. It is shown that the description of this information is more compact in this coordinate frame. Furthermore, it is demonstrated that the acquisition limitations can be overcome by introducing an approximation scheme based on this coordinate frame. These techniques are tested on ex-vivo datasets to assess their fidelity and sensitivity. Finally, these techniques are applied in-vivo on a group of healthy volunteers, where 2D DTI slices of the LV were acquired at end diastole and end systole, using cardiac dedicated diffusion MR acquisition. Results demonstrate the advantages of using curvilinear coordinates both for the analysis and the approximation of cardiac DTI information. Resulting in-vivo fibre architectures were found to agree with previously reported studies on ex-vivo specimens. The outcome of this work can open the door for clinical appli cations and cardiac electrophysiology modelling, and improve the understanding of the left ventricular structure and dynamics.
Dissertation
Distribution and fibre field similarity mapping of the human anterior commissure fibres by diffusion tensor imaging
by
Toussaint, Nicolas
,
Charles-Edwards, Geoffrey David
,
Lin, Jean-Pierre
in
Bioengineering
,
Biomedical Engineering and Bioengineering
,
Brain Mapping - methods
2010
Object
The anterior commissure is a critical interhemispheric pathway in animals, yet its connections in humans are not clearly understood. Its distribution has shown to vary greatly between species, and it is thought that in humans it may convey axons from a larger territory than previously thought. The aim was to use an anatomical mapping tool to look at the anterior commissure fibres and to compare the distribution findings with published anatomical understanding.
Materials and methods
Two different diffusion-weighted imaging data sets were acquired from eight healthy subjects using a 3 Tesla MR scanner with 32 gradient directions. Diffusion tensor imaging tractography was performed, and the anterior commissure fibres were selected using three-dimensional regions of interest. Distribution of the fibres was observed by means of registration with T2-weighted images. The fibre field similarity maps were produced for five of the eight subjects by comparing each subject’s fibres to the combined map of the five data sets.
Results
Fibres were shown to lead into the temporal lobe and towards the orbitofrontal cortex in the majority of subjects. Fibres were also distributed to the parietal or occipital lobes in all five subjects in whom the anterior commissure was large enough for interhemispheric fibres to be tracked through. The fibre field similarity maps highlighted areas where the local distances of fibre tracts were displayed for each subject compared to the combined bundle map.
Conclusion
The anterior commissure may play a more important role in interhemispheric communication than currently presumed by conveying axons from a wider territory, and the fibre field similarity maps give a novel approach to quantifying and visualising characteristics of fibre tracts.
Journal Article
Mechanically Powered Motion Imaging Phantoms: Proof of Concept
by
Schnabel, Julia A
,
Clough, James R
,
Oksuz, Ilkay
in
Angular velocity
,
Embedding
,
Energy storage
2019
Motion imaging phantoms are expensive, bulky and difficult to transport and set-up. The purpose of this paper is to demonstrate a simple approach to the design of multi-modality motion imaging phantoms that use mechanically stored energy to produce motion. We propose two phantom designs that use mainsprings and elastic bands to store energy. A rectangular piece was attached to an axle at the end of the transmission chain of each phantom, and underwent a rotary motion upon release of the mechanical motor. The phantoms were imaged with MRI and US, and the image sequences were embedded in a 1D non linear manifold (Laplacian Eigenmap) and the spectrogram of the embedding was used to derive the angular velocity over time. The derived velocities were consistent and reproducible within a small error. The proposed motion phantom concept showed great potential for the construction of simple and affordable motion phantoms
Screen Tracking for Clinical Translation of Live Ultrasound Image Analysis Methods
by
Schnabel, Julia A
,
Matthew, Jacqueline
,
Toussaint, Nicolas
in
Aspect ratio
,
Augmented reality
,
Field of view
2020
Ultrasound (US) imaging is one of the most commonly used non-invasive imaging techniques. However, US image acquisition requires simultaneous guidance of the transducer and interpretation of images, which is a highly challenging task that requires years of training. Despite many recent developments in intra-examination US image analysis, the results are not easy to translate to a clinical setting. We propose a generic framework to extract the US images and superimpose the results of an analysis task, without any need for physical connection or alteration to the US system. The proposed method captures the US image by tracking the screen with a camera fixed at the sonographer's view point and reformats the captured image to the right aspect ratio, in 87.66 +- 3.73ms on average. It is hypothesized that this would enable to input such retrieved image into an image processing pipeline to extract information that can help improve the examination. This information could eventually be projected back to the sonographer's field of view in real time using, for example, an augmented reality (AR) headset.