CHICAGOMagnetic resonance imaging (MRI) mammography
was able to detect eight of nine breast malignancies, some of which had been
missed on conventional film mammography, in 196 young women at high risk for
hereditary breast cancer.
The only cancer missed by MRI mammography was a ductal
carcinoma in situ (DCIS), reported Rene S. Shumak, MD, of the Department of
Medical Imaging, Sunnybrook & Women’s College Health Sciences Centre,
In her presentation at the 86th Annual Meeting of the
Radiological Society of North America (RSNA), Dr. Shumak said that women who
are at risk for hereditary breast cancer because they carry a gene mutation for
breast cancer or have a personal or very strong family history of the disease
have a 50% chance of developing cancer by age 50 and an 85% chance by age 80.
Dense Breast Tissue
Breast cancer among high-risk women often occurs at a young age
when breast tissue is dense. Conventional mammography is of limited
Dr. Shumak and her associates tested MRI mammography in 196
high-risk women over the course of a year. These included 96 women who were
carriers of a breast cancer gene mutation, 17 who had a first-degree relative
with a breast cancer gene mutation, and 83 who had a strong family history of
The first 65 women in the study had MRI mammography using a
dedicated bilateral breast coil to obtain bilateral coronal images; the
remaining women had MRI mammography done with sagittal images. Whenever an
abnormality was found on initial MRI breast screening, the woman returned for
follow-up high-resolution, dynamic, fast and delayed fat-saturated MRI.
Nine Cancers Detected
In this study, nine breast cancers were detected: All were 1.5
cm or less in size, and all were node negative. MRI mammography detected eight
of the nine cancers, compared with two for clinical breast examination, four
for mammography, and five for ultrasound.
Of 12 patients who underwent biopsy based solely on MRI
findings, 2 were found to have breast cancer. In two
cases, at biopsy the lesion could not be seen on directed ultrasound and
required MRI-guided wire localization.
When compared with ultrasound and mammography, only MRI was
able to pick up those cases involving dense glandular tissue and a small lesion
(less than 0.5 cm). Ultrasound found larger lesions with dense glandular
tissue, and mammography spotted lesions in breasts with less dense glandular
One 46-year-old woman with a BRCA1 gene mutation and highly
dense breasts had no detectable abnormality on mammography. On MRI mammography,
the first image obtained after administration of a contrast agent showed an
oval, rapidly enhancing lesion. With some washout of the contrast medium, on
the fourth image obtained after contrast administration, an enhanced rim around
a malignancy persisted, and this lesion proved to be invasive carcinoma.
A 50-year-old women with a BRCA1 mutation and slightly less
dense breast tissue had a small focally enhancing lesion on an initial MRI
mammography scan and a rim-enhancing lesion on a high-resolution image.
Subsequent directed ultrasound uncovered a hypoechoic 0.5-cm carcinoma.
Dr. Shumak concluded that MRI can detect breast malignancies
that are missed by mammography, clinical breast examination, and screening
ultrasound. Although directed ultrasound is a very
effective method for targeting abnormalities that are found on MRI mammography,
MRI-guided biopsy sometimes is needed to sample tissue from suspicious areas of