4D MRI scans of child heart help predict outcome of heart surgery
29 November 2006
Atlanta, Georgia, USA. Magnetic resonance imaging
(MRI) of the hearts of children with heart defects can be used to create
three-dimensional models to test the effect of surgical procedures. This can
help surgeons plan optimum surgery for each child’s congenital heart defect.
Georgia Tech and Emory University researchers have developed an
innovative new technology that will help paediatric cardiac surgeons design
and test a customized surgical procedure before they ever pick up a scalpel.
With a better understanding of each child’s unique heart defect, surgeons
could greatly improve the likelihood that children with complex defects
requiring multiple surgeries over a period of several years could have
smoother recoveries and an improved quality of life after their operations.
|A model illustrating
the direction and strength of blood flow through a child's pulmonary
artery and connecting veins after certain changes are made to its
The technology, known as image-based surgical planning and developed with
the help of paediatric cardiologists and paediatric surgeons at The
Children’s Hospital of Philadelphia (CHOP) and Emory University, creates a
three-dimensional model of the child’s heart with data from the child’s MRI
scans at different times in the cardiac cycle, also called a 4D MRI. The
models allow surgeons to visualize the direction of blood flow and determine
any energy loss in the heart. So if a surgeon were planning a certain
correction to an area of a child’s heart, a model created by the system
would show the surgeon how well blood would flow through the newly
The goal of the Georgia Tech/Emory project is to create a complete system
that allows surgeons to get a detailed look at the child’s heart functions
with the new MRI system, design surgical procedures for optimum
post-operative performance and evaluate the heart’s performance with a
sophisticated blood flow computer simulation.
The work was presented this
month at the American Heart Association’s Scientific Sessions meeting in
Chicago and has been published in Circulation and the Annals of
“We use the MRI images and time data to create
models of these children’s vascular systems and hearts to simulate how they
currently work and how they could work after surgery,” said Ajit Yoganathan,
Ph.D., a co-principal investigator on the project and associate chair of the
Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and
Emory University. “The goal is to improve the quality of life for these
children by understanding their current physiology and finding the best way
to optimize the surgery for that particular child.”
While the program
isn’t yet ready for use by surgeons outside the project, it could be
available in about three to five years, Yoganathan said.
normal heart has two ventricles or lower chambers of the heart used for
pumping blood through the body, two out of every 1,000 babies in the United
States are born with just one lower chamber. Considered one of the most
complex congenital heart defects, a single-ventricle heart often leads to
congestive heart failure if not repaired.
Patients with this defect often
undergo multiple surgeries to reconfigure the pulmonary and systemic systems
in operations called Fontan repairs, a reconfiguration that diverts the
blood flow coming to the right side of the heart directly to the lungs so
that the heart no longer has to pump blood to the lungs. Staged over several
years, these surgeries are a common, but not always successful, option used
for treating a single-ventricle defect.
After a less-than-optimal
operation, children sometimes experience a reduced capacity to perform
physical activities and may experience blood clotting and ventricle
arrhythmias. The Georgia Tech/Emory surgery planning system could eliminate
the need for additional surgeries by optimizing early surgeries.
research is meant to get at the root of the ‘failing’ Fontan, investigating
why these pumping chambers fail in the hopes of devising new strategies to
give these children a second chance in life. Using advanced imaging and
bioengineering tools, the project hopes to describe how blood flows in this
type of circulation and how this blood flow might be altered to extend the
life of the patients,” said Mark Fogel, M.D., director of cardiac MR in the
Cardiac Center at Children’s Hospital and a key collaborator on the project.
The Georgia Tech/Emory team began work on a system to help surgeons address
the unique challenges of Fontan repair. In essence, the system determines
how any geometric change in the current heart configuration will change
blood flow and strength.
To perfect their system, researchers combined
computational and experimental studies to create a method of assessing an
optimum vessel configuration. The group worked heavily with fluid dynamic
studies in the lab to get the most accurate simulation of blood flow.
Another tool, developed by a team led by Jaroslaw Rossignac Ph.D. in Georgia
Tech’s College of Computing, is a program that allows for manipulation of a
3-D model of a patient’s cardiovascular system to try out different
configurations with a mouse. Once the surgeon has the desired configuration,
the new vascular configuration can then be tested with the Image-based
surgical planning system to see how well the new surgical procedure would
Georgia Tech and Emory completed the engineering aspects of the
study with assistance from the University of North Carolina at Chapel Hill.
The MRI and patient studies were gathered at CHOP and Children’s Healthcare
of Atlanta’s Sibley Heart Center.
While the patient MRI database is
currently only accessible to project participants, researchers are working
with the National Institutes of Health (NIH), which funded the project, to
open the database to other paediatric cardiologists and cardiac surgeons.