Early Breast Cancer Detection Using 3D Ultrasound Tomography

Institution: University of California, San Diego
Investigator(s): Thomas Nelson, M.D. -
Award Cycle: 2005 (Cycle 11) Grant #: 11IB-0035 Award: $149,879
Award Type: IDEA
Research Priorities
Detection, Prognosis and Treatment>Imaging, Biomarkers, and Molecular Pathology: improving detection and diagnosis

Initial Award Abstract (2005)
Mammography is the current "gold standard" for diagnosing breast disease but most cancers arise in dense ductal tissue so lesion identification in women with dense breasts and at increased risk for breast disease is particularly challenging. Ultrasound is an important adjunct to mammography to identify, characterize and localize breast lesions and is not limited in dense breasts. Ultrasound also requires no radiation or compression. However, ultrasound is operator-dependent and a lack of consistency between centers limits its widespread acceptance. To be truly useful ultrasound must provide more consistent, high quality imaging with human variation. This research proposes a new approach to ultrasound imaging wherein we will construct a breast ultrasound scanner to image the entire breast. This scanner design will provide consistent, high quality images of breast tissues especially in women with “dense breasts” or young women at increased risk who require more frequent imaging. Also, the scanner will not use compression or radiation so the comfort level will increase while any radiation risk will decrease. The resulting high quality images should improve visualization of dense breasts will improve early identification of breast cancer and help localize those cancers so they may be biopsied or treated more cost-effectively.

This IDEA project will design, construct and begin testing a dedicated ultrasound scanner for the entire breast. We call this a volume breast ultrasound (VBUS) scanner. In this project we will design a scanning table for the pendulant breast. Since we will use no compression, stabilization cups corresponding to standard bra cup sizes will provide a comfortable fit for scanning. The scanner will be automated and make a complete scan in less than 30 seconds under operator control. We will build each part of the scanner and validate that performance meets our specifications. After the scanner is built we will perform a series of additional tests to make sure the scanner operates properly and produces high quality breast images. After those tests we will image a few cadaver breast specimens. The final phase of the project will be to image volunteers to determine if the scanner is ready for clinical evaluation. We plan to apply for additional funding for the clinical evaluation phase. Additional collaborative work with Dr. John Boone at the University of California, Davis will compare volume breast ultrasound data to dedicated breast CT (computerized tomography) data to verify the performance of the imaging system.

Final Report (2008)
Overview: Early detection of breast cancer is the most effective way to improve survival. Mammography is the current “gold standard” for diagnosing breast disease. Most cancers arise in dense ductal tissue however, so lesion identification in women with dense breasts and those at increased risk for breast disease is particularly challenging. Ultrasound is an important adjunct to mammography to identify, characterize and localize breast lesions and is not limited in dense breasts. Further benefits of ultrasound include no radiation or compression. However ultrasound is operator dependent and the lack of consistency between centers limits widespread acceptance. This project designed, constructed and tested a volume breast ultrasound (VBUS) scanner for imaging the entire pendant breast. The initial project focused on the design and construction of the VBUS scanner. After construction we performed a characterization of scanner performance in a series of test objects and a limited number of volunteers.

Specific Aims Completed: The specific aims of this IDEA project were to: SA1 - Design a volume breast ultrasound scanner: We have (1) accomplished an initial design for a prototype scanner.

SA2 - Construct and assemble scanner subsystems and complete scanner integration: We have (2) constructed a scanning table with a curved patient supporting top with an opening and apparatus for containing the pendant breast; (3) constructed a scanning gantry using a series of computer controlled rotational and linear motors; (4) constructed a device to hold the ultrasound transducer to attach to the gantry apparatus; (5) written software to control the scanner motion and acquire ultrasound images during scanning; and (6) written software to reconstruct and display the volume data from the acquired ultrasound images

SA3 - Characterize the performance of the volume breast ultrasound to assess suitability for patient imaging: Initial results have led to several scanner improvements. We also have obtained (7) preliminary images from test objects and human volunteers.

Barriers: In 2007 we modified the volunteer protocol of SA3 to obtain data from 20 volunteers at UC Davis to validate VBUS scanner performance against the breast CT scanner developed at UC Davis with CBCRP funds. Two factors have complicated obtaining our anticipated study data: 1) the ultrasound image acquisition system has not been available due to protracted negotiations between UCSD and the vendor and 2) the team at UC Davis has been unable to arrange the necessary commitment of resources to conduct the approved study. These two considerations have seriously reduced our ability complete SA3. During this period we did image two patients at both UCSD and UC Davis with very good results.

Accomplishments: We have accomplished the majority of our specific aims. Initial volunteer scans have been very encouraging. We have completed scanner improvements to enhance patient comfort during scanning and image quality including a more detailed analysis of scanner performance. Scanner operation is fully automatic which is a key part of achieving our longer-term goal of standardizing scanning protocols. By meeting these goals the VBUS scanner addresses several shortcomings of current breast ultrasound scanning approaches by standardizing the acquisition of ultrasound data from the entire breast. The improved visualization of breast architecture, particularly in women with dense breasts or young women at increased risk who require more frequent imaging, should improve early detection and localization of breast disease, especially in dense breasts where ultrasound is superior to mammography. Additionally, the volume data produced will be useful to improve guidance of biopsy and interventional procedures. Finally, the VBUS scanner will be excellent for imaging contrast agents for blood flow and tumor perfusion imaging.

Next Steps: We had anticipated performing a more extensive clinical evaluation however, due to unforeseen factors that has been delayed and we will conduct that study as part of a recently funded CBCRP competitive renewal. We are in the process of developing an imaging validation study at UCSD to obtain the correlative data from MRI. We have purchased a dedicated ultrasound image acquisition system currently being integrated with the VBUS scanner and we expect to be fully operational in the next month and ready to resume patient/volunteer studies.

Symposium Abstract (2007)
The goal of this IDEA project is to improve early detection of breast cancer by building an ultrasound scanner that can image the entire breast thus standardizing ultrasound breast imaging to provide high quality images improving detection of nonpalpable breast cancers that cannot be seen with mammography in women at high risk of breast cancer, especially in women with dense breasts.

Specifically, our goal was to design, construct and begin testing a dedicated volume breast ultrasound (VBUS) scanner for the entire breast. To date we have successfully designed the scanner, a scanning table for the pendant breast and the necessary imaging and computer systems to obtain volume breast images. The scanner uses no compression, is fully automated and makes a complete scan in less than 30 seconds under operator control. We have performed a series of measurements to characterize scanner performance with satisfactory results. We also have obtained images from normal volunteers as part of validating performance and determining that the scanner is ready for clinical evaluation. We are preparing to expand our clinical imaging to a broader clinical trial.

The volume breast ultrasound (VBUS) scanner described in this proposal utilizes a novel imaging technology to improve breast cancer detection and diagnosis. First, the scanner obtains a volume data set for the entire breast improving visualization of breast tissue and providing more precise localization of suspicious breast lesions. Second, the scanner provides a standardized scanning environment reducing much of the variability present in current ultrasound scans leading to more accurate diagnosis and a better prognosis. Third, the scanner uses volume imaging and spatial compounding to reduce speckle and improve lesion conspicuity.

The significantly improved image quality and tissue contrast permits detection of breast lesions smaller than the current median size of 11 mm with mammography. Additionally, since ultrasound does not use radiation VBUS scanner offers a lower risk alternative to mammography. VBUS may offer a lower cost alternative to full-field-digital-mammography and magnetic resonance imaging. VBUS volume data also provides improved localization of breast lesions that could be used to guide biopsy devices with improved precision. Development of a VBUS scanner is expected to assist in identifying and diagnosing breast cancer earlier thereby reducing mortality risk and improving the quality of life for the patient.

Classification of breast computed tomography data.
Periodical:Medical Physics
Index Medicus: Med Phys
Authors: Nelson TR, Cerviño LI, Boone JM, Lindfors KK.
Yr: 2008 Vol: 35 Nbr: 3 Abs: Pg:1078-86

Simulation of mechanical compression of breast tissue.
Periodical:IEEE transactions on bio-medical engineering
Index Medicus: IEEE Trans Biomed Eng.
Authors: Kellner AL, Nelson TR, Cerviño LI, Boone JM.
Yr: 2007 Vol: 54 Nbr: 10 Abs: Pg:1885-91