Two approaches are taken which should both be usable to increase breast cancer detection and certainty of diagnosis in those patients in which mammography is equivocal. Most cancerous lesions of the breast, and many other malignant masses, are known to have a hypervascular ring around their periphery with abnormal small- vessel flow characteristics. 10 MHz, continuous wave (CW) Doppler has detected those abnormalities, offering 90% specificity for breast malignancy; however, it is too cumbersome to be practical. Pulsed Doppler and color flow imagers are still too insensitive to detect the small vessel flow. We will study whether the increased sensitivity from use of large sample volumes contributes more to cancer detection and diagnosis than high resolution in pulsed color flow Doppler systems. The study will also develop and evaluate 3-D color flow scanning of the breast and 3-D display of the vasculature along with some pulse echo data to determine whether the morphologic distortions produced by malignant lesions can be discerned better with addition of 3-D visualization to real time color flow imaging. This will be done in a reusable in-vitro kidney model and in rabbit tumors to determine sensitivity to tissue blush and small, discrete vessels and in symptomatic women with light compression in views employed for the mammograms. The evaluations of 3-D visualization and system sensitivity measurements will be performed with and without gas bubble contrast agents for enhancement of small vasculature. Demonstration and evaluation of multiview (compound) 3-D imaging of breast vasculature will be accomplished by 3-D image unwarping from manual point registration. Phase aberration correction methods will be employed to create ultrasound beam trajectories and possibly speed of sound images for eventual refraction corrections. Combination of all the information from this project should, in the long run, increase the number of detected lesions in dense breasts and should provide enough specificity to avoid a large fraction of unnecessary biopsies and assure vigorous needle biopsy or lumpectomy in those lesions which remain suspicious. It is also anticipated that detection and diagnosis of cancer in other body parts will eventually be enhanced by these techniques.
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