Invasive Diagnostic Technology

Guided Biopsy

Many biopsy methods rely on image guidance to help the radiologist or breast surgeon to precisely locate the lesion within the breast. Imaging may be necessary when a lesion cannot be felt during physical examination and is only detected through examination by mammography, MRI or ultrasound. It may also be necessary to use imaging to assure that a mass felt during examination is indeed the same abnormality noted on a mammogram, MRI or ultrasound. If image guidance is required, the consideration typically focuses on what type of image guidance is most appropriate for the biopsy.

Often, a biopsy is recommended after discovery of a suspicious lesion by mammography or physical exam. However, only a low percentage of women undergoing biopsy actually have breast cancer. The positive predictive value of mammography has been estimated to be less than 30% and possibly as low as 15%. Only 20% of the biopsies result in positive diagnosis of a malignant lesion. Therefore, about 80% of the breast biopsies performed in US result in negative results. The Imaging technologies available to date for guided biopsies are: X-ray (stereotactic), ultrasound and MRI. MRI is utilized when ultrasound or mammogram guided biopsy is not specific in screening the area of interest. As mentioned above, the conventional 2-D ultrasound lacks the adequate specificity while MRI bears high costs.

If a non-invasive test would be available that could reliably rule out malignancy, many women could safely avoid costly and stressful biopsies. Several technologies including MRI, ultrasound, PET scan and scinti-mammography have been proposed for this purpose. Based on an analysis by the Agency for Healthcare Research and Quality, none of the above modalities has sufficient sensitivity and specificity. Some new technologies (i.e., IDUS™) are aimed at reducing the number of false positive biopsies, decreasing the number of unnecessary biopsies, providing better patient care and reducing the staggering economic burden.