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Cardiovascular Biomechanics and Ultrasound Laboratory |
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Imperial College London, Department of bioengineering |
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RESEARCH
PROJECTS |
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Machine Learning
in Cardiovascular Imaging and Biomechanics We
are developing novel deep learning techniques to improve segmentation and
motion tracking of the heart from echo and MRI images. This includes
strategies to accurately scale up to 3D images, and using motion-enhancement
to improve segmentation.
To
enhance cardiac geometric modelling, we developed next generation algorithms
for 3D reconstruction of cardiac geometries images that can be directly
supervised by image labels, which has superior performance than PCA
statistical shape models and marching cubes. The algorithm can be used to
enhance future deep learning mesh reconstructions from images.
To
bring biomechanics research to the next level, we are currently developing deep
learning algorithms to generate results of cardiovascular flow simulations
and cardiac finite element simulations, to accelerate the adoption of
biomechanical analysis in clinical practices for disease detection,
evaluation and prognosis. For
example, we are developing CFD-supervised networks as well as Physics
Informed Neural Networks (PINN) for rapid estimation of flow fields for
curved blood vessels of a range of geometries. We developed a PINN framework
applied to cardiac images that can back compute the myocardial stiffness and
contractile stress as well as predict finite element myocardial stresses,
which requires very little training time. We further developed a deep
learning framework for synthetic generation of highly realistic cranial
aneurysm geometries, which can be controlled to have specific values of
clinical shape parameters. This framework can be used to support training a
flow prediction network, and can be used to understand effects of specific
geometric feature on fluid dynamics
Improving
Echocardiography Heart Function Evaluation Echocardiography
evaluation of heart function is widely performed, and is important for
diagnosis and to determine if interventions should be performed. However,
many current heart function parameters have shortcomings, and we have
proposed ways improvements: -
the
Ejection Fraction (EF) parameter is widely used to evaluate cardiac health,
but it is a poor indicator when the heart undergoes geometric remodelling
during disease. We proposed a correction for EF to resolve this, and showed
that our new corrected parameter have stronger prognosis capabilities for
rehospitalization. -
in
fetal echocardiography, strain measurements in the literature have widely
varying results, and lack precision. We performed careful measurements of 2D
versus 3D cardiac strains from echocardiography, and show the essential
reasons for their disagreement, and point out factors that potentially cause
the variability. -
Microscopy
demonstrated that the myocardium has microscopic sheetlet structures, and it
is hypothesized that sheetlet sliding is important to cardiac function. We
showed via simulations that sheetlet sliding is some effects on function in
the normal heart, but the effects are amplified in hypertrophic hearts. Use
these links below for details.
Biomechanics
of the Human Fetal Heart and Fetal Heart Intervention Biomechanical
stimuli are important stimuli for proper fetal heart development, but we understand
very little of it. The biomechanical environment of the fetal heart, its
growth and remodelling in response to abnormalities, and the
mechanobiological mechanism responsible for malformations are all not
well-understood. Abnormalities during mid-gestation that disrupts the normal
biomechanical environment can lead to congenital heart malformations. In some
such cases, catheter-based intervention on the fetal heart can correct the
abnormalities to prevent the malformation at birth. There is much room for
such interventions to improve, and biomechanics modelling can help such an
effort. We use a range of techniques to study the fetal heart and fetal heart
intervention, including fetal echocardiography image processing,
computational fluid dynamics simulations, and finite element modelling of
myocardial mechanics. Use
these links below for details.
Embryonic
Heart Biomechanics The
embryonic heart is the first organ to develop. It undergoes a fascinating developmental
process, starting out as a simple tube and develops into a 4-chamber
structure by week 8 of gestation, and sustaining a tremendous amount of
growth and highly dynamic remodelling. We hypothesize that mechanical forces
are important stimuli to proper early cardiac development, seek to understand
the biomechanics of embryonic hearts of both normal small animal embryos and
those of animal embryonic models of congenital malformations, as well as
understand the mechanobiological pathways towards these malformations. We use
advanced techniques of image-processing and image-based simulations to obtain
greater details in our studies. Use
these links below for details.
Materials Technology Towards a
Blood Pump with Low Blood Damage Blood
pumps save countless lives every day, and include the implanted type (LVAD),
those in the ICU (ECMO), and those in the surgical suite (heart-lung
machine). However, they impose high stresses on blood and induce foreign
surface reactions to cause thrombosis, and thromboembolic complications. We
pursue various strategies and technologies to attain a blood pump with low
blood damage. For example, we fabricate superhydrophobic and superhemophobic surfaces to enable slip flow in blood
pump surfaces to reduce stresses, we seek new ways of pumping blood, such as
using electro-active polymers and utilizing resonance in roller pumping. Use
this link below for details.
Superhydrophobic Hemostatic
Materials Technology Traditional
hemostatic devices rely on absorbing blood to bring
about clotting and hemostasis. We recently
discovered that a nanofibrous superhydrophobic material provides an
alternative and excellent approach towards hemostasis.
The material is strongly repellent towards blood, and easily prevents blood
loss, which is the #1 reason for death in serious injuries. However, the
nanofibers can still cause fast clotting to bring about fast hemostasis. Since the material did not wet while blood
clots, blood is only connected to the path via nano-contacts after clotting,
and this enables extremely easy detachment of the patch from the wound.
Finally, the material is also repellent to microbial attachment and thus has
natural antimicrobial properties. We are currently enhancing this technology,
and pursuing commercialization. Use
this link below for details.
Placenta
and Placenta Disease Biomechanics The
placenta is an important organ during pregnancy, whose health has great
short- and long-term impact on the health of both the mother and the child.
Pregnancy diseases such as Intrauterine Growth Restriction have surprisingly
high prevalence and consequent mortality and morbidity, even in developed
countries, and there is no proven method to prevent or treat the disease. We
advocate that biomechanical approach to studying the placenta can provide new
insights that can lead to better detection, diagnosis, and even treatment.
Examples of our approach include mechanical testing and constitutive
modelling on normal and diseased human placenta samples, investigating the
use of elastography to detect placenta diseases, and image-based biomechanics
simulations on placenta and umbilical blood vessels in health and disease. Use
this link below for details.
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Collaborations We are very collaborative in our work. If you have questions
about our work, or if we can help you in your research work, please feel free
to contact us. |