13 research outputs found
Towards Realistic Ultrasound Fetal Brain Imaging Synthesis
Prenatal ultrasound imaging is the first-choice modality to assess fetal
health. Medical image datasets for AI and ML methods must be diverse (i.e.
diagnoses, diseases, pathologies, scanners, demographics, etc), however there
are few public ultrasound fetal imaging datasets due to insufficient amounts of
clinical data, patient privacy, rare occurrence of abnormalities in general
practice, and limited experts for data collection and validation. To address
such data scarcity, we proposed generative adversarial networks (GAN)-based
models, diffusion-super-resolution-GAN and transformer-based-GAN, to synthesise
images of fetal ultrasound brain planes from one public dataset. We reported
that GAN-based methods can generate 256x256 pixel size of fetal ultrasound
trans-cerebellum brain image plane with stable training losses, resulting in
lower FID values for diffusion-super-resolution-GAN (average 7.04 and lower FID
5.09 at epoch 10) than the FID values of transformer-based-GAN (average 36.02
and lower 28.93 at epoch 60). The results of this work illustrate the potential
of GAN-based methods to synthesise realistic high-resolution ultrasound images,
leading to future work with other fetal brain planes, anatomies, devices and
the need of a pool of experts to evaluate synthesised images. Code, data and
other resources to reproduce this work are available at
\url{https://github.com/budai4medtech/midl2023}.Comment: 3 pages, 1 figur
Nonlinear analysis to quantify movement variability in human-humanoid interaction
Nonlinear analysis can be applied to investigate the dynamics of time-ordered data. Such dynamics relate to sensorimotor variability in the context of human-humanoid interaction. Hence, this dissertation not only explores questions such as how to quantify movement variability or which methods of nonlinear analysis are appropriate to quantify movement variability but also how methods of nonlinear analysis are affected by real-world time series data (e.g. non-stationary, data length size, sensor sources or noise). Methods are explored to determine embedding parameters, reconstructed state spaces, recurrence plots and recurrence quantification analysis. Additionally, this thesis presents three dimensional surface plots of recurrence quantification analysis with which to consider the variation of embedded parameters and recurrence thresholds. These show that three dimensional surface plots of Shannon entropy might be a suitable approach to understand the dynamics of real-world time series data. This thesis opens new avenues of applications in human-humanoid interaction where humanoid robots can be pre-programmed with nonlinear analysis algorithms to evaluate, for instance, the improvement of movement performances, to quantify and provide feedback of skill learning or to quantify movement adaptations and pathologies.
This PhD thesis is open access under the licence of Creative Commons Attribution Share Alike 4.0 International and code and data is available at https://github.com/ mxochicale/phd-thesis/ (Xochicale, 2019). The github repository has been created to make this work reproducible and perhaps help others to advance this field. Throughout the thesis links to R code (6) are provided in the caption of figures in order to reproduce their results. See Appendix A for details on how code and data is organised and how results can be replicated in this thesis
Design and discussion of a (reusable) Sustainability Dashboard of Open Source Tools
Our presentation and resulting Mentimeter survey data from RSE London South East
https://rslondon.ac.uk/rslondonsoutheast2023/abstracts/#ft6 in July 202
AI-Enabled Assessment of Cardiac Systolic and Diastolic Function from Echocardiography
Left ventricular (LV) function is an important factor in terms of patient
management, outcome, and long-term survival of patients with heart disease. The
most recently published clinical guidelines for heart failure recognise that
over reliance on only one measure of cardiac function (LV ejection fraction) as
a diagnostic and treatment stratification biomarker is suboptimal. Recent
advances in AI-based echocardiography analysis have shown excellent results on
automated estimation of LV volumes and LV ejection fraction. However, from
time-varying 2-D echocardiography acquisition, a richer description of cardiac
function can be obtained by estimating functional biomarkers from the complete
cardiac cycle. In this work we propose for the first time an AI approach for
deriving advanced biomarkers of systolic and diastolic LV function from 2-D
echocardiography based on segmentations of the full cardiac cycle. These
biomarkers will allow clinicians to obtain a much richer picture of the heart
in health and disease. The AI model is based on the 'nn-Unet' framework and was
trained and tested using four different databases. Results show excellent
agreement between manual and automated analysis and showcase the potential of
the advanced systolic and diastolic biomarkers for patient stratification.
Finally, for a subset of 50 cases, we perform a correlation analysis between
clinical biomarkers derived from echocardiography and CMR and we show excellent
agreement between the two modalities
Intraoperative Needle Tip Tracking with an Integrated Fibre-Optic Ultrasound Sensor
Ultrasound is an essential tool for guidance of many minimally-invasive surgical and interventional procedures, where accurate placement of the interventional device is critical to avoid adverse events. Needle insertion procedures for anaesthesia, fetal medicine and tumour biopsy are commonly ultrasound-guided, and misplacement of the needle may lead to complications such as nerve damage, organ injury or pregnancy loss. Clear visibility of the needle tip is therefore critical, but visibility is often precluded by tissue heterogeneities or specular reflections from the needle shaft. This paper presents the in vitro and ex vivo accuracy of a new, real-time, ultrasound needle tip tracking system for guidance of fetal interventions. A fibre-optic, Fabry-Pérot interferometer hydrophone is integrated into an intraoperative needle and used to localise the needle tip within a handheld ultrasound field. While previous, related work has been based on research ultrasound systems with bespoke transmission sequences, the new system—developed under the ISO 13485 Medical Devices quality standard—operates as an adjunct to a commercial ultrasound imaging system and therefore provides the image quality expected in the clinic, superimposing a cross-hair onto the ultrasound image at the needle tip position. Tracking accuracy was determined by translating the needle tip to 356 known positions in the ultrasound field of view in a tank of water, and by comparison to manual labelling of the the position of the needle in B-mode US images during an insertion into an ex vivo phantom. In water, the mean distance between tracked and true positions was 0.7 ± 0.4 mm with a mean repeatability of 0.3 ± 0.2 mm. In the tissue phantom, the mean distance between tracked and labelled positions was 1.1 ± 0.7 mm. Tracking performance was found to be independent of needle angle. The study demonstrates the performance and clinical compatibility of ultrasound needle tracking, an essential step towards a first-in-human study