DALLAS--Magnetic resonance imaging (MRI) of the breast has recently
generated much excitement as a means of improving the specificity
of mam-mography and thus reducing the number of negative biopsies,
Steven E. Harms, MD, of Baylor University Medical Center, said
in an interview with Oncology News International.
Dr. Harms, director of magnetic resonance imaging, and his colleague
at Baylor, Duane P. Flamig, PhD, director of magnetic resonance
research, have developed a technique known as RODEO that further
enhances MRI sensitivity, particularly in women who have a compromised
The technique may prove especially useful in evaluating the breast
for additional cancer sites in patients with a suspected solitary
lesion on mammography, to determine eligibility for breast conservation
(see Rodeo image ).
"We felt that the currently available commercial MRI equipment
really did not provide adequate resolution or give us the confidence
to call abnormal areas, so we developed a new technology based
on a pulse sequence," Dr. Harms said.
RODEO (rotating delivery of excitation off-resonance) uses a combination
of radiofrequency (RF) pulses, magnetic fields, computers, and
a breast coil "antenna" placed over the breast, to image
breast tumors as small as 3 mm. "Using RF pulses, we can
excite water and selectively suppress fat or silicone or both
simultaneously," he said.
When the fat signal is eliminated from the MR image, contrast-enhanced
tumors appear as bright spots surrounded by dark fat. This helps
physicians determine whether the mass is a tumor, cyst, hemorrhage,
fat necrosis, or scar tissue. With silicone suppression, the technique
can distinguish tumor masses from silicone leaks.
Dr. Harms said that RODEO may play a major role in the staging
of breast cancer. He described a patient with a breast abnormality
on MRI that could not be visualized with magnification mammog-raphy
or sonography. "At surgery, she had disease extending exactly
as shown on the MRI," he said.