Researchers at Johns Hopkins have for the first time
used a chemical marker detected by proton magnetic
resonance spectroscopic imaging, or MRSI, to successfully
diagnose breast cancer. The diagnostic technique produces
pictures of choline within breast tumors.
In the study, researchers from the Russell H. Morgan
Department of Radiology and Radiological Science at Hopkins
demonstrated that choline signals analyzed by MRI were
significantly elevated in malignant tumors in 15 of 18
patients studied. Three of the cases could not be included
because of technical failures such as patient movement or
computer failure during the scanning procedure.
The results are published in the December-January
issue of the Journal of Magnetic Resonance
Scientists have long known that cancers contain
elevated levels of choline, a product of membrane
synthesis, but the Johns Hopkins study is believed to be
the first to demonstrate its value in accurately
identifying breast tumors.
MRSI of the breast does not appear likely to be
cost-effective as a routine screening tool for breast
cancer but may prove to be a viable noninvasive alternative
to biopsy in cases with positive mammography or clinical
breast exam results, said Michael A. Jacobs, the lead
researcher for the study. "What MRSI does provide is
information about the molecular environment of breast
tumors, which also may be useful in designing therapeutic
interventions for patients."
Proton magnetic resonance imaging uses the water
content in tissue to produce images by measuring signals
emitted after subjecting the tissue to high magnetic fields
but provides no information on the chemical or molecular
aspects of the tissue being imaged. Combining proton MRI
with spectroscopy allows the scientists to differentiate
intracellular components of the cell and signals emitted by
certain biochemicals, such as choline.
In the study, 15 patients who had been referred for
MRI evaluation after previous examination had revealed
breast tumors underwent regular breast MRI to identify the
lesion. These studies were followed by MRSI scanning to
determine if choline signals in the tumors could be
adequately imaged using spectroscopy. Biopsies performed
after the imaging revealed that eight of the tumors were
malignant carcinomas, and seven were benign. MRSI showed
elevated choline levels in all eight of the malignant
"These data are proof of principle and strongly
suggest that MRSI can serve as an important adjunct to the
routine MRI scan that may aid physicians in making a
diagnosis of breast cancer," Jacobs said. "We can envision
a time when this procedure may even replace the need for
biopsy in some cases and provide the basis to follow
treatment strategies in certain cases of breast cancer.
However, more research is needed to fully understand the
potential impact of these findings."