The earlier that breast cancer is detected, the better the patient’s chance of survival. Therefore, screening is important. Mammography has played a significant role in detecting cancers early; however, it cannot always detect the types of abnormalities present — such as whether they are malignant or benign — and it is not very sensitive in detecting cancer in dense breasts.

Dr. Steven P. Poplack from Dartmouth-Hitchcock Medical Center in Lebanon, N.H., and his colleagues tested whether electromagnetic properties in breast tissue could be imaged to help determine types of abnormalities. As reported in the May issue of Radiology, the researchers tested 150 women — 53 with normal and 97 with abnormal mammograms — with three electromagnetic imaging methods: electrical impedance spectroscopy, microwave imaging spectroscopy and near-IR spectral tomography.

A total of 62 patients with abnormal and 36 with normal mammograms received electrical impedance and, among those who had abnormal results, malignancies were found in 16, fibrocystic disease sites were found in 32, fibroadenomas in nine and other benign abnormalities in five. Microwave imaging spectroscopy was performed on 80 patients with abnormal and 50 with normal mammograms. Of those in the abnormal group, malignancies were found in 26, fibrocystic disease in 41, fibroadenomas in eight and other benign abnormalities in five. And, finally, 58 patients with abnormal and 42 with normal mammograms received near-IR spectral tomography. In the abnormal group, malignancies were found in 18, fibrocystic disease in 31, fibroadenomas in seven and other benign abnormalities in two.

Overall, electromagnetic imaging provided contrast ratios of between 150 and 200 percent between abnormal and normal breast tissue — meaning that the abnormalities were visible in the images. The researchers found that the electrical impedance spectroscopy helped discriminate between normal and abnormal breast tissue but did not characterize the type of abnormality present. The microwave imaging spectroscopy showed some promise of differentiating malignancies from normal or benign conditions, but improvements are needed in the image resolution. The near-IR spectral tomography results also showed promise for differentiation, but with a limited resolution threshold.

Overall, the researchers believe that electromagnetic breast imaging shows promise for differentiating abnormalities but that further study is needed.