Rather than comparing the mammogram image in question to every image of breast cancer in a computer database, the new approach compares the mammogram in question to selected images that are most highly ranked for their information content. This is analogous to how a Google search first returns a list of only those websites that it determines to have the most important and useful information on the words entered in the search.
In a pilot study that will be presented in August at the 48th Annual Meeting of the American Association of Physicists in Medicine in Orlando, the approach enabled computers to maintain their high level of accuracy while performing faster analysis. Such speed and efficiency will be important as such image databases rapidly grow larger and more complex.
Knowledge-based computer-assisted detection (CAD) systems compare mammogram images to those of known cases of breast cancer in order to aid radiologists in their diagnosis. However, as clinical image libraries grow rapidly in mammography practice, knowledge-based CAD systems get slower and less efficient.
In efforts to prevent such systems from bogging down, Duke's Georgia D. Tourassi, Ph.D. (Georgia.firstname.lastname@example.org) will present a Knowledge-Based Computer Assisted Detection (KB-CAD) system that analyzes breast masses using the principles of information theory.
When a new, unknown case is presented for analysis, the KB-CAD system compares the case to mammography images in the database. It retrieves cases that are similar, those that share certain visual features and properties. If the unknown case is similar enough to a known case of breast cancer, then this would suggest the presence of cancer.
Although diagnostically accurate, this practice becomes inefficient as the image database increases in size. Therefore, the researchers incorporate an additional approach.
Instead of comparing the new unknown case with all mammography images stored in the knowledge database, the researchers restrict the analysis to the stored cases that are most informative. The selection of the most informative cases is done using an image indexing strategy based on the concept of "image entropy." Image entropy represents a measure of the disorder or complexity in the image. An image that is all black or white has zero entropy. An image of a checkerboard has low entropy—it consists of an equal number of light and dark pixels. Complex images with more uniform distributions of many pixel intensity levels have higher entropy and are considered more informative in the context of the Duke system.
Normal breast tissue "can be as complex as a tumor," Tourassi says. "This is precisely the reason mammographic diagnosis is such a challenging task. Our database inlcudes normal cases as well in the decision-making process."
In the recent pilot study, the Duke researchers applied their technique to a database of 2,300 mammography images. With entropy indexing, the researchers compared a sample image to the top 600 most informative, cutting down their CAD system's processing time by one-fourth, to less than 3 seconds per query. The researchers expect to launch a larger study in a year to evaluate the clinical impact of this new approach.
Meeting Paper: TU-D-330A-8, "Information-Theoretic CAD System in Mammography: Investigation of An Entropy-Based Indexing Scheme for Improved Computational Efficiency and Robust Performance," Tuesday, August 1, 2006, 2:54-3:06 PM, Room 330A. Click Here for Technical Abstract
Presented at: 48th Annual Meeting of the American Association of Physicists in Medicine, July 30-August 3, 2006, Orange County Convention Center, Orlando, FL. Click Here for Meeting Homepage
AAPM is a scientific, educational, and professional organization of more than 6,000 medical physicists. Headquarters are located at the American Center for Physics in College Park, MD. Publications include a scientific journal ("Medical Physics"), technical reports, and symposium proceedings.
Basque researchers turn light upside down
23.02.2018 | Elhuyar Fundazioa
Attoseconds break into atomic interior
23.02.2018 | Max-Planck-Institut für Quantenoptik
A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.
In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...
A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.
By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
23.02.2018 | Physics and Astronomy
23.02.2018 | Health and Medicine
23.02.2018 | Physics and Astronomy