More than 15 years after its initial clinical application, breast MR remains an imaging modality in search of a role.
Mammography and breast ultrasound will be the standards for breast imaging for the foreseeable future, said Dr. Gillian Newstead, a radiologist at New York University, at an RSNA refresher course.
"In the patient whose mammographic and ultrasound findings are inconclusive, contrast MR might provide additional information that could help with diagnosis," Newstead said. "But we need to evaluate breast MR in many more patients. Some large studies that will be conducted in the next couple of years should help us sort out which patients will benefit from MR breast imaging."
Mammography, the first-line imaging modality, has a number of well-known limitations, she said. The limitations include difficulty with imaging dense breast tissue, artificially augmented breasts, surgical scars, and changes in the post-radiation therapy breast. MRI may help with all those issues, but especially the latter two, Newstead said.
Potential applications of MR in breast imaging include use as an alternative staging method, screening of high-risk patients (which is being addressed in a National Cancer Institute-sponsored trial), and evaluation of patients who have already been treated for breast cancer.
Other observations about contrast MR breast imaging reveal:
- Rapid enhancement of malignant lesions
- Delayed (beyond 10 minutes) enhancement of benign lesions
- Irregular, focal enhancement of malignancies
- Diffuse lesions remain problematic
- Lack of data on ductal carcinoma in situ
- Lack of a standard or optimal imaging technique
- Wide variation in magnet types and radiologists' preferences
The key to answering many of the unresolved questions is increased clinical evaluation, Newstead said. She noted that only 13,000 of the 8.5 million MR studies conducted in 1995 involved breast imaging, and only 1,400 breast MR exams utilized contrast.
