Introduction

The strength of ultrasound (US) is its use of non-ionizing radiation, high resolution, low cost, and high sensitivity and specificity when used for solving focal symptomatic problems and providing easy image guidance for needle biopsy. The rapid advances in US technology over the past few years have benefited breast US along with more general applications. The marked improvements in the capabilities of digital scanners with sophisticated composite transducers have led to better imaging and Doppler, with lower noise floors and improved spatial resolution. The extended field of view available on many systems facilitates comparison of textures across the whole breast and is useful for follow-up studies. Three-dimensional data sets achieve similar benefits and allow reslicing that permits the identical view to be repeated for accurate follow-up comparisons. The introduction of microbubble contrast agents not only improves the display of small vessels but also makes three-dimensional Doppler studies more informative. In addition they provide the opportunity to perform functional studies by timing the wash-in and wash-out of a bolus injection; whether or not this has clinical value remains to be explored.

Despite the many advances listed in the preceding paragraph current weaknesses of breast US include operator dependence and reproducibility, low specificity when used as a screening tool, poor detection of microcalcification, underestimation of tumor extent, and failure to utilize more than 5% of the available information in the returning US signal.