PORTLAND, Ore. – Researchers at Oregon Health & Science
University's Advanced Imaging Research Center (AIRC) are developing a
new imaging method that may provide a clearer diagnosis of breast
cancer. The research is published in the latest issue of the journal
Magnetic Resonance in Medicine. AIRC Director Charles Springer, Ph.D.,
is senior author, and AIRC Manager, Xin Li, Ph.D., is first author of
the new paper, along with William Rooney, Ph.D., AIRC faculty.
Professor Springer also holds appointments in OHSU's Cancer Institute
and Department of Biomedical Engineering.
"This technique involves a new method for interpreting information
gathered through MRI," explained Springer. "The technique involves
recognizing that certain properties of MRI signals can change during
the examination, much like the changing of a camera's shutter speed. On
a camera, a fast shutter speed can make a speeding car look as if it is
standing still. A slower shutter speed may result in a photo showing
the car blurring past the camera. This principle, when correctly
applied to MRI imaging, can provide more accurate information. In the
case of MRI, the blurring is not of the actual image, but of the time
courses of the MRI signals."
Magnetic resonance imaging technology combines the use of
powerful magnets and radio wave pulses. The magnet influences the
magnetization of the body's water molecules. The radio signals that are
received from this can be converted into a visual representation.
The shutter speed concept allows researchers to adjust the
mathematics of the computer program analyzing the signals to account
for the movement of water molecules in and out of cellular compartments
in diseased and healthy tissue. When the MR shutter speed increases,
this movement appears to slow. In the case of tumors, using shutter
speed analysis not only more clearly indicates the locations of tumors,
it also allows researchers to distinguish between malignant tumors and
benign tumors.
To conduct this research project, the scientists analyzed data
from six patients identified as having breast tumors with mammograms
(X-rays.) In procedures conducted by New York research collaborators
Drs. Wei Huang, Alina Tudorica, and Thomas Yankeelov of Stony Brook
University and Brookhaven National Laboratory, the patients were
injected with a contrast agent, which acts like an MRI dye and provides
clearer images. The patients received MRI scans as the dye passed
through the tumors. The time courses of the MRI signals were analyzed
with the shutter speed model. The results showed hot spots only in
images of malignant tumors but not in the benign tumors (three of the
cases). This complete distinction was not the case using the standard
MRI technique, and there was no distinction using mammography.
Pathology results on these tumors confirmed the accuracy of the new MRI
testing.
"While continued research is required, we believe shutter speed
analyzed MRI could become a powerful tool for the diagnosis and
treatment of breast cancer and almost any other form of cancer, as well
as many other pathologies," explained Springer. "The shutter speed is a
very general concept and applies to a great many different MRI
techniques."
"We are fortunate to have recruited Dr. Springer and his team
to lead the imaging research activities at OHSU and the OHSU Cancer
Institute." said Grover C. Bagby Jr., M.D., Director of the OHSU Cancer
Institute. "His 'shutter-speed' model has the potential of changing our
approach to cancer screening in general and may also play a role in
determining the early effects of treatment. The findings also provide a
unique opportunity for cancer researchers to unravel the basic
molecular causes of the different image signatures."
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