Ultrasound Computed Tomography for Breast Lesion Detection

Institution: University of California, San Diego
Investigator(s): George Leopold, M.D. -
Award Cycle: 1995 (Cycle I) Grant #: 1IB-0322 Award: $45,382
Award Type: IDEA
Research Priorities
Detection, Prognosis and Treatment>Imaging, Biomarkers, and Molecular Pathology: improving detection and diagnosis

Initial Award Abstract (1995)
Breast cancer is a major health care problem that affects an increasing number of younger women. X-ray mammography provides an excellent tool for diagnosis but has a high false positive rate (i.e., wrongly indicating the existence of a cancer tumor) and is possibly even less sensitive in women with dense breasts. Sonography, or ultrasound (a diagnostic technique in which deep structures of the body are visualized by recording the reflection of high frequency sound waves) is an attractive way to examine questionable areas detected on the mammogram, but it is complicated to perform. Furthermore, modern high-resolution sonography instruments image only a small portion of the breast at a time and it is often difficult to identify the suspicious region.

We have developed an ultrasound computed tomography (USCT) scanner that makes cross-sectional images of the breast (CT is a technique that uses computer technology to generate images of thin "slices" of tissue from multiple views around all sides of the object). These novel images are similar to optical holograms and are based on fundamentally different principles from that of conventional sonography. Our new approach uses circular rings of up to 1024 transducers (devices that change sound waves into electrical signals) that surround the entire breast. A single cross-sectional image covers a very large area eight inches (20 cm) in diameter and requires less than one second to acquire. In preliminary studies, this system has been able to display very small details (0.5 mm at 1 MHz) over a very large image field of view.

This research will examine the suitability of this technique for breast imaging and will examine its ability to identify the many types of lesions in the breast. Two groups of volunteers will be recruited for study: 1) subjects referred for mammography screening will expand our experience with normal anatomy for a wide range of breast types, and 2) subjects with confirmed breast lesions will be studied along with x-ray mammography and sonography for comparison. This technology has the potential to improve the early detection of breast cancer and to reduce the number of unnecessary biopsies.

Final Report (1997)
The objective of this research is to examine in a clinical setting the suitability of our unique ultrasound system for imaging the breast. If successful, this new method may lead to improvements in early detection of breast cancer or in the accuracy of diagnosis thereby reducing the need for biopsy. This new scanner makes cross-sectional image "slices" by transmitting sound waves into the breast from all sides and reconstructing the images in a computer similar to the operation of a x-ray computed tomography scanner (CT or "CAT"). These novel images are based on fundamentally different principles from that of a conventional ultrasound scanner or x-ray mammography and therefore need to be evaluated for their ability to distinguish between normal tissues and the many types of "lumps" or masses that may occur in the breast. The images produced by this experimental system also provide a view of the entire cross-section of the breast (8 inches in diameter) at high resolution, a feature that is not available with conventional ultrasound scanners that are able to see only two or three inches of the breast at a time. Several different methods have been developed to reconstruct and enhance the images which need to be evaluated in the patient studies.

Two groups of subjects are being studied: 1) those with normal breasts but varying sizes and densities, and 2) women with specific symptoms evident on their mammograms. Each subject has a routine screening mammogram and, if indicated, an ultrasound scan as part of their regular care. Ultrasound CT images of the entire breast are then acquired in sequential slices from the nipple to the chest wall. Considerable progress is being made in understanding the appearance of different tissues as well as their unique ultrasound "signature" that can be measured with the experimental system. Preliminary results in very dense breasts which are difficult to image well with mammography are very encouraging. The technical quality of the ultrasound CT images and the potential limitations of the method are now better understood. Detailed measurements in the laboratory may be helpful to design improvements in the computer processing and electronics. The sequential slices have also been assembled into a three-dimensional life-size transparent image of the entire breast. These three-dimensional images are viewed by doctors on the computer screen or printed out as a hologram--a true three-dimensional photograph in which all internal structures are clearly visible. The hologram allows the physician to literally "reach inside" tissue to make measurements, consider biopsies or plan potential surgery. This type of display has proved very helpful for interpretation of the ultrasound CT images.

Ultrasound scatter fields in the breast: in vivo results with diffraction tomography
Periodical:Medical Physics
Index Medicus: Med Phys
Authors: Janee HS, Andre MP, Ysrael MZ, Olson LK, Leopold GR
Yr: 1996 Vol: 23 Nbr: 6 Abs: Pg:1108

Reduction of phase aberration in a diffraction tomography system for breast imaging
Periodical:Acoustical Imaging
Index Medicus: Acoust Imaging
Authors: Andre MP, Janee HS, Otto GP, Martin PJ
Yr: 1996 Vol: 22 Nbr: Abs: Pg:151-157

Analysis of scatter fields in diffraction tomography experiments
Periodical:Acoustical Imaging
Index Medicus: Acoust Imaging
Authors: Janee HS, Jones JP, Andre MP
Yr: 1996 Vol: 22 Nbr: Abs: Pg:21-26

Three-dimensional breast US: holographic display of ultrasound CT
Index Medicus: Radiology
Authors: Andre MP, Ysrael MZ, Olson LK, Janee HS, Schulz RA, Otto GP
Yr: 1995 Vol: 197 Nbr: P Abs: Pg:443

High speed data acquisition in a diffraction tomography system with large-scale toroidal arrays.
Periodical:International Journal of Imaging Systems & Technology
Index Medicus: Int J Imaging Systems & Technol
Authors: Andre MP, Janee HS, Otto GP, Martin PJ
Yr: 1997 Vol: 8 Nbr: 1 Abs: Pg:137-147

Simultaneous spatial and velocity vector mapping with diffraction tomography.
Periodical:Acoustical Imaging
Index Medicus: Acoust Imaging
Authors: André MP, Janee HS, Barrett TK, Spivey BA, Martin PJ.
Yr: 1997 Vol: 23 Nbr: Abs: Pg:583-588