Emerging technologies in breast cancer detection

Abstract

While screening mammography is recognized as the most effective method for early detection of breast cancer, this modality has limitations that are the driving force behind efforts to refine existing mammography technologies and develop new ones offering improved detection of breast cancer. Full-field digital mammography (FFDM) systems use digital detectors to convert x-ray photons to digital signals for display on high-resolution monitors. These systems offer capabilities not provided by conventional film-screen mammography. Contrast-enhanced mammography utilizes the basic biological principle that aggressive cancers are associated with increased vascularity. Iodinated contrast agents--the same used in computed tomography (CT) examinations--are administered through an injection in a vein usually in the arm. They distribute throughout the blood system, and x-ray imaging shows increased contrast in areas where they concentrate. Tomosynthesis acquisition involves acquiring multiple images of a stationary compressed breast at different angles during a short scan. The individual images are then reconstructed into a 3D series of thin high-resolution slices. The slices can be displayed individually or in a dynamic ciné mode. The individual slices reduce tissue overlap and structure noise relative to standard 2D projection mammography, with a total dose comparable to that required for standard screening mammography. Initial efforts are underway to develop prototype systems to achieve high-resolution, whole-breast 3D ultrasound images that are co-registered with digital mammograms. This technology has the potential to improve specificity in breast imaging studies, particularly in dense breasts. Computer-aided detection (CAD) programs are intended to help radiologists identify suspicious lesions that may otherwise be overlooked. CAD software works similarly to a spellchecker and has the potential to increase the detection of cancer Magnetic resonanace imaging (MRI) is a generally accepted diagnostic procedure for a number of breast related indications. Its greatest strength is that it is very sensitive to tumors. If a suspected area does not exhibit contrast agent uptake, the probability that it is malignant is very small. Conversely, its specificity is poorer. If the area does show enhancement, it may or may not be a tumor. Further imaging or biopsy may be needed to resolve the question. Ultrasound holds promise as a method for detection of cancers in women with dense breast tissue, which is often problematic with conventional film-screen mammography. Ultrasound has also assumed an important role in breast imaging, as an adjunct to diagnostic mammography for biopsy guidance, palpable mass evaluation, and serial evaluation of benign masses.