|
Lung Imaging Workshop: Technology Transfer Diagnostic
Imaging Program (DIP), DCTD, NCI Washington, D.C.
Jan 12-13th, 1998
1. Report: Technology Transfer
Workshop
A. Lung cancer imaging and image processing as a
model for technology transfer B. Specific areas in lung cancer imaging
that could be enhanced by technology transfer C. Recommendations and
priorities for technology transfer D. Recommendations regarding
mechanisms
2. List of Attendees
A. Presenters B. Business Representatives
C. NCI Representatives D. Invited Presenters (unable to
attend, reviewed report)
3. Presentations and
Abstracts
A. Monday, January 12, 1998
1. Introduction and Overview of Current
Imaging Methods 2. Feature Extraction, Lesion Characterization and
Classification 3. Multi modality: Image Reconstruction and Image
Restoration Methods 4. Planer: Image Registration and Change Point
Analysis 5. Hardware Implementation 6. DARPA:
Representative Image Processing Applications of Dual Use
B. Tuesday, January 13, 1998
7. Summary of Workshop
1. REPORT: TECHNOLOGY TRANSFER WORKSHOP
Section A. Lung cancer imaging and image processing
as a model for technology transfer
Clinical Rational. The issues relating to
the clinical need for lung cancer imaging are well recognized in the published
literature and are briefly summarized below:
- Lung cancer is usually not detected early, and thus
may be diagnosed at an advanced stage, where intervention or therapy is less
effective. Although the incidence rate of lung cancer is lower than for breast
and prostate cancer, the mortality rate of lung cancer is the highest for all
cancers in both men and women.
- The sensitivity for lung nodule detection of
peripheral lung cancers by conventional chest radiographs is still very low.
There is a critical need for alternative imaging strategies and image processing
techniques to improve the sensitivity of detection. Similarly, the limitation of
the response characteristics of screen-film detectors, and the wide variety in
image quality that is seen in chest radiographs, greatly impacts the accuracy of
image interpretation.
- There is a critical need to consider longitudinal
studies for early detection of lung cancer for asymptomatic patients, using
different imaging modalities, such as for high-risk patients. A cost effective
means to automatically and quantitatively measure these early changes as soon as
possible by image processing is a worthwhile goal.
- There is a need to improve follow up for diagnostic
imaging studies to improve intervention, such as surgery or medical therapy,
perhaps using tomographic and functional imaging methods, and provide a more
effective and quantitative measure of the progress or response to treatment of
the disease.
Digital Planar Chest Radiography.
Currently the majority of lung cancers are detected from conventional
chest radiographs, because of the cost effectiveness of this imaging modality.
The technical requirements for film digitization are straightforward with
standard film digitization equipment. In addition, since the late 1980's there
has been a major transition from conventional film-based X-ray techniques to
digital sensors, using either storage phosphors or, more recently, flat panel
digital detectors, that allow real-time imaging and potentially real-time
quality control procedures. These digital sensors permit several improvements
that include: (a) dual-energy imaging to partially remove the rib cage to
improve cancer detection by image subtraction, and (b) the introduction of image
processing methods to improve and potentially standardize image interpretation.
The use of digital sensors and the potentially widespread implementation of PACS
systems in the near future pose very critical problems for image interpretation
using computer monitors, computer-processed images using hardcopy devices, and
related problems for remote diagnosis or teleradiology using low-end computer
monitors.
X-Ray Tomography. There is an increasing
interest in performing longitudinal studies using either digital X-ray chest
imaging or X-ray CT. Similarly, alternative cost effective X-ray imaging methods
such as tomosynthesis, or limited angle tomography, have recently been proposed
for longitudinal studies, that may allow an approximate 3D image representation
of the chest. Tomosynthesis may partially reduce the problems with overlapping
structures in relation to lung nodule detection, where the nodules may be wholly
or partly overlapped with the rib cage. Tomosynthesis is still in the early
development stage. Although it offers the advantage of a 3D approach without
significantly increasing radiation dose, it poses additional new problems in
terms of optimized reconstruction methods, image artifacts, and need for image
processing to improve in-plane image contrast. Similarly, the introduction of
low dose X-ray CT, such as spiral imaging methods, either for longitudinal
studies or diagnostic follow-up investigations, has stimulated increasing
interest in alternative image reconstruction methods to potentially reduce dose,
and methods for improved feature extraction using raw data in the frequency
domain. Although the practicality of some of the alternative reconstruction
methods needs further review, the advances in low dose X-ray CT clearly pose new
image processing problems for image reconstruction, image restoration, image
registration and 3D image fusion with other modalities. Similar problems arise
for other tomographic modalities such as MRI, PET, SPECT and coincidence SPECT,
that are proposed for improved tissue characterization of lesions such as lung
nodules. Allowance needs to be made in imaging processing methods for the
varying response characteristics of these sensors.
Computer Assisted Diagnostic (CAD) methods.
The 2D and 3D planar and tomographic modalities generate new issues in
terms of cost effective and efficient image interpretation, and the potential
improvement of observer performance or reduction of observer variability in
reading images. Further development of optimized computer assisted diagnostic
(CAD) methods are required, as a A second opinion @ strategy, for the very
extensive 2D or 3D image data sets generated by different sensors, where image
reading requirements pose a serious obstacle for efficient patient throughput.
The performance of CAD methods has been recently shown to be dependent on the
response characteristics of film digitizer, such as the gray scale
characteristics or spatial resolution. There is a need to develop CAD methods
that are less dependent on the digital sensor characteristics, i.e. a more
generalized CAD method is required. CAD methods also need to be developed for
longitudinal studies with different sensors. One clinical example is the CAD
detection of peripheral lung nodules, but other applications for lung imaging,
such as extension to hilar lymph nodes, or airway involvement, should be further
explored.
Virtual bronchoscopy. Virtual
bronchoscopy is an emerging visualization technology that may become a useful
diagnostic tool for evaluation of the airways. Several published have shown it
to provide a more complete evaluation of stenoses of the airway (due to
inflammation, scarring, tumor, or post-lung transplant). One of virtual
bronchoscopy's most important strengths is how well it displays
three-dimensional data to referring clinicians. Potential applications of
virtual bronchoscopy still under investigation include detection of
endobronchial lesions which do not cause stenosis (e.g., early detection of
carcinoma) and its use to guide transbronchial biopsy of lesions just beyond the
airway wall (hidden from, yet accessible to the bronchoscopist). Such use could
decrease the need for mediastinoscopy. Several commercial virtual endoscopy
systems which include the capability to perform virtual bronchoscopy are
currently available. However, research on virtual bronchoscopy is still in its
infancy, and validation in larger numbers of patients, methodology and user
interface issues, and potential artifacts are still being evaluated. Image
processing methods which may prove useful for virtual bronchoscopy include 3D
CAD methods and 3D image registration of functional imaging data sets with the
anatomical image data sets.
Technology Transfer Issues. It is clear
from workshop discussions that new algorithm approaches in image processing for
all modalities are required to enhance the outcome of the rapid advances in
hardware development. These methods are pre-eminently mathematical and the
subject of intensive research in the fields of mathematics, computer science,
electrical engineering, and physics. These investigators are predominately
university-based and funded by NSF and DOD/DARPA. This workshop demonstrated the
critical need for both timely access to these more sophisticated image
processing techniques and the necessity for translational research to allow
these software tools to be tailored and optimized for specific medical
applications such as lung imaging. The implementation of some form of
centralized imaging processing software resource was considered important to
provide a means for reduction of research time lines for lung imaging within the
medical imaging research community. This could be similar to the NCI
implementation of common resources for the human genome project.
Summary. There was a strong consensus
that lung imaging was an important clinical model and image processing was an
excellent technical model for technology transfer. There are not only problems
to be solved but exciting new techniques that can solve them. Similar technology
transfer for hardware research is also an area to be actively considered in the
future. Specific research areas where technologies were identified as suitable
for technology transfer are identified in Section B, recommended actions items
are briefly outlined in Section C and priorities for technology transfer are
described in Section D.
Section B. Specific areas in lung cancer imaging
that could be enhanced by technology transfer
1. Image registration and change point
analysis.
- Need for optimized inter-modality image registration,
as required for time series or longitudinal studies, using chest radiographs or
perhaps x-ray limited angle tomography.
- Need for inter-modality registration, e.g.,
radiographs registered to tomographic modalities such as x-ray CT, PET or SPECT
images or with x-ray limited angle tomography.
- Need to examine new techniques, for example:
- using internal anatomical landmarks as opposed to
rigid registration, such as feature-based or site-model image
registration
- deformable registration models such as image-warping
registration methods
- multi-resolution wavelet approaches with selective
sub-image registration at different scales for computational efficiency
- evaluation of constraints for stabilizing
image-matching procedures for small localized structures such as lung nodules;
i.e. to allow for deformation of normal anatomy over time or anatomical
variation in imaging protocols using all imaging modalities.
- Need for exploring alternative and more robust metrics
for classification of changes in images over time should be investigated that
are also site specific, such as spatial scan statistics and modified statistical
approaches for improved likelihood estimation of change.
2. Image fusion.
- 3D multi-modality image fusion and related image
segmentation, single-scale spatial image modeling approaches that include image
warping, knowledge-based methods, and multi-spectral feature-space methods such
as clustering methods including fuzzy logic. These methods are required for
integrated 3D displays, visualization and virtual reality such as virtual
bronchoscopy, i.e. for anatomical and functional imaging for tomographic
modalities as required for classification, or follow-up studies in lung cancer
using x-ray CT, PET and SPECT.
3. Image restoration.
- New approaches for image resolution or image contrast
restoration are required to compensate for either:
(a) the limited response
characteristics of the detector such as for tomographic nuclear imaging; (b)
to compensate for influence of photon transport, such as for x-ray detectors
(planar or tomographic imaging) and nuclear detectors (SPECT, PET).
4. Image reconstruction.
- Need alternative 3D tomographic image reconstruction
methods such as for x-ray CT, MRI, PET or SPECT, tomosynthesis or limited angle
tomography. Examples include the feasibility of the limited field of view or
localized reconstruction methods for all tomographic modalities. There is a need
to investigate the stability of linear inverse problems and feasibility of
non-linear solutions to non-ideal image tomographic reconstruction problems to
facilitate, for example, the use of x-ray flat panel detectors in limited angle
tomography.
5. Image enhancement.
- More optimized techniques are required for improving
the visual interpretation of images using soft copy devices, such as high
resolution computer monitors, or hard copy image techniques and related issues
of image perception.
6. CAD: Automatic feature extraction
methods.
- Improved feature extraction is clearly required from
both the perspective of CAD methods and longitudinal studies. Feature extraction
is also important for image registration. This should include all imaging
modalities, such as planar film (digitized), digital x-ray detectors, and
tomographic imaging modalities. and related longitudinal studies. It is
therefore important to develop feature extraction for both 2D and 3D image sets,
as required for lung nodule detection, and to allow nodule and related features
to be computed in cases where the nodule is overlapped with the rib cage.
Similarly, extraction of improved features to distinguish nodules from other
similar structures, such as blood vessels, is necessary to reduce the false
positive detection rate. Feature extraction and related segmentation is required
for functional tomographic modalities for diagnostic follow-up, including PET
and SPECT.
- The feasibility of alternative multi-resolution
approaches for feature extraction may be of interest, as opposed to single scale
methods, such as the use of wavelet transforms that have both direction and
frequency information within discrete frequency band widths. Several new methods
have been actively developed for defense application in the DOD sector including
automatic target recognition (ATR). Methods for selection of wavelet bases
should possibly be considered for potentially more optimum performance for
certain applications.
- Other alternative transforms for improved feature
extraction, sensitive to small structures such as nodules, are important to
explore. Similarly, feature extraction using the raw image in the frequency
domain for tomographic images may be promising as an alternative to the spatial
domain (reconstructed images).
7. CAD: Automatic classification
methods.
- Alternative classification methods should be explored
that may provide for more robust and stable solutions to difficult pattern
recognition problems. Approaches may include nonlinear discrimination and
recognition techniques, such as neural networks and/or fuzzy systems, based on
significant advances made over the last decade. In addition, these may include
recent advances in evolutionary computation, where optimal fuzzy/neural
classifiers may be optimized through random variation and selection. Similarly,
evolutionary methods (such as genetic algorithms and evolutionary programming)
should prove useful for feature subset selection and transformation, leading to
parsimonious models that reduce the false positive detection of lung
nodules.
- There is a critical need to reduce both the training
time and classification speed for pattern recognition methods as applied to
medical image analysis as addressed below without sacrificing sensitivity or
specificity.
8. Hardware implementations.
- The feasibility of close-to-real-time and
cost-effective image processing or CAD methods should be explored using hardware
approaches. Examples include field programmable gate arrays, as required for:
(a) training and application of neural networks, or (b) application of wavelet
transforms or other transforms implemented on compatible filter banks for
feature extraction.
- Alternative approaches using advances in workstation
parallel CPU design and efficient parallel code implementation should be
considered.
- The practicality of other non-traditional methods need
to be reviewed carefully such as optical image processing as applied to
high-order Fourier and wavelet transforms for feature extraction or optical
correlation of images.
Section C. Recommendations and Priorities for
Technology Transfer.
1. Information Dissemination.
NCI should be proactive for reaching out and
identifying leading non-medical researchers working on image processing and
drawing them into imaging problems such as lung imaging. NCI should be
specifically proactive in promoting interactions between such investigators and
medical imaging specialists using approaches such as:
- Workshop format with input from specialists outside
the medical imaging sector such as the current workshop.
- Internet Web site with links to other federal
resources such as NSF and DARPA. (Not required to build an all-encompassing Web
site, but to provide links to resources.)
- Presentations by NCI representatives at a broad
spectrum of regional and national meetings. (Example: both medical and
non-medical meetings such as SPIE Medical Imaging, IEEE signal processing and
IEEE EMB-sponsored national meetings.)
- Contacting university-sponsored research or grant
offices with program announcements or problem statements to determine the level
of expertise and interest within basic science departments in these
institutions. Alternatively, one could coordinate this effort as an
institutional effort within NIH and link, for example, with computational
mathematics divisions of NSF and DARPA. This is being pursued in the broader
field of biomedical engineering by seminars and programs recently sponsored by
NIH.
2. Infrastructure.
- Development of image databases and mechanisms for
distribution. Issues that need to be addressed include generation of multiple
modality image data bases, ground truth, format (DICOM/ACR) standards, other
database information (such as ACoS and SEER tumor registry findings).
- Timely availability of image
data bases with ground truth from leading imaging technologies to allow
non-medical image software investigators to test the feasibility of new
algorithms.
- Standardized metrics for objective comparison and
evaluation of algorithms. This issue is critical as metrics used to evaluate
detection of an abnormality greatly influence the measured performance.
Similarly, standards for training algorithms are important, for example,
classifiers such as neural networks or the incorporation of a priori
knowledge in the image processing chain.
- Access to data could be possibly limited to
investigators that are funded by any federal agency or private foundation. For
example, they may state requested access to this data base in submitted
proposals on algorithm design and adhere to recommended standards and metrics
for evaluation. (This will allow controlled access to the data that should not
be disseminated or published without the corresponding evaluation
techniques.)
Section D. Recommendations regarding
mechanisms.
1. Existing Models and Possible NCI/NIH
extension.
Consider emulating the DARPA model in the area of
computational mathematics, where formulated contracts within academia and
industry are developed. This was specifically performed proactively to establish
scientific program priorities and thus produce specific software components or
modules for broad DOD program driven applications. DARPA is currently successful
in getting its grantees to move more rapidly by constraining the infrastructure,
i.e. by reducing the number of different software platforms, languages and data
formats. The users built new infrastructure on the common platform and exchanged
the results of their work in a highly interactive way. This approach is intended
to enhance progress at multiple sites and reduce duplication of effort in
building software tools and infrastructure to perform research tasks. DARPA also
proactively fosters interchange of ideas and results at workshop meetings so
that tools and successful ideas move quickly from grantee to grantee. One could
consider interagency agreement/programs such as with NSF and/or DARPA to
leverage off existing programs, for dual use technology or technology transfer,
and enhance timely dissemination to the medical imaging community. NSF and DARPA
representatives at the workshop have expressed interest in this inter-agency
approach at the program level for computational mathematics.
2. Alternative approaches using NCI/NIH
programs.
NCI could consider using existing resource grants or
equivalent programs, but with the suggested modifications:
- Technology transfer funding from NIH is
nontraditional, and should have some differences in program management built-in.
This includes issues such as:
- Partnering with medical and non-medical scientists
from universities, national and DOD laboratories and industry
- Infrastructure support for all participants
- Award size to accommodate multi-center efforts and
software dissemination.
- Grant review process needs to emphasize either
research-and-development-type proposals or contract-type proposals that may be
required for infrastructure support.
- Cooperation among technology-transfer grantees, and
with other grantees including industry.
- Infrastructure support: Preliminary funds to stimulate
new developments through common software, data interchange, platforms and image
data bases. These issues are considered critical for partnering with either
non-medical institutions or industry.
3. Concerns in relation to success of technology
transfer.
- There is a need to critically address continuity of
support for technology transfer to ensure that real progress can be made
throughout both the development and evaluation research timetables.
- Continuity of experience and knowledge is important
for effective management and related technical and scientific communication
between medical and non-medical scientists, recognizing differences in cultures,
and allowing for continued research transition of non-medical scientists to new
imaging problems. Some form of exchange of scientists between such laboratories
is necessary.
- Intellectual property issues need to be addressed in
relation to technology transfer mechanisms similar to that practiced within the
DOD/ DARPA.
- Timely and wide dissemination of technology is
required, with full documentation for software implementation, to allow improved
research timetables similar to the very successful NCI Human Genome
Project.
2. LIST OF ATTENDEES
Workshop attendees are from university and medical
research institutions, IPA=s from NCI, NSF and DARPA, and Editors or Associate
Editors from leading IEEE journals in computer software.
A. Presenters.
Carlos A. Berenstein, Ph.D.
IPA: (University of Maryland): Program Director,
Division of Mathematical Sciences, NSF, Arlington, VA National Science
Foundation, 4201 Wilson Blvd., Room 1025, Arlington, VA 22230 (703)
306-1870, FAX (703) 306-0555, cberenst@nsf.gov
Laurence P. Clarke, Ph.D.
IPA: Special Assistant, DCTD, NIH, Bethesda, MD
Associate Editor: IEEE TMI, Editorial Board, SMRI and MRI Professor of
Radiology and Physics, Director of Research, Department of Radiology,
Program Leader: Moffitt Digital Medical Imaging Program (DMIP)
Department of Radiology, College of Medicine, University of South Florida,
12901 Bruce B. Downs Blvd., MDC 17, Tampa, FL 33612-4799 (813) 975-7833 or
7835, FAX (813) 979-6724, clarke@rad.usf.edu
Carey Floyd, Ph.D.
Professor of Radiology and Biomedical Engineering
Duke University, Radiology/Biomedical Engineering, Medical Center, Box 3949,
Durham, NC 27710 (919) 684-4138, FAX (919) 684-2711 or 3934,
cef@deckard.mc.duke.edu
David Fogel, Ph.D.
Editor: IEEE Transactions on Computational Methods
Executive Vice President and Chief Scientist Natural Selection, Inc.,
3333 N. Torrey Pines Ct., Suite 200, La Jolla, CA 92037 (619) 455-6449, FAX
(619) 455-1560, dfogel@natural-selection.com
Matthew Freedman, MD, MBA
Associate Professor of Radiology and Clinical, Director
of the Division of Imaging Science and Information Systems, Georgetown
University Medical Center
Freedman@isis.imac.georgetown.edu
Dennis Healy, Ph.D.
IPA: (From Dartmouth, Mathematics Department) Applied
and Computational Mathematics Program, DARPA/DSO, 3701 N. Fairfax Drive,
Arlington, VA 22203-1714 (703) 696-0143, FAX (703) 696-3999,
dhealy@darpa.mil
Maryellen L. Giger, Ph.D.
Editor: Academic Radiology, Associate Editor: IEEE-TMI
and Medical Physics. Associate Professor of Radiology, University of Chicago
University of Chicago, Radiology Department, MC2026, 5841 So. Maryland Ave.,
Chicago, IL 60637 (773) 702-6778, FAX (773) 702-0371,
m-giger@uchicago.edu
Michael McNitt-Gray, Ph.D.
Assistant Professor Medical Imaging Division,
Department of Radiological Sciences, CHS, AR-265, UCLA School of Medicine, 10833
Le Conte Ave., Los Angeles, CA 90024-1721 (310) 206-3285, FAX (310)
206-2967, mmcnitt-gray@mail.rad.ucla.edu
Loren T. Niklason, Ph.D.
Assistant Professor of Radiology, Harvard Medical
School, Boston, MA Radiological Sciences and Tech., Mass. General Hospital,
Edwards Res. Bldg., Room 517, Fruit Street, Boston, MA 02114 (617) 726-6757,
FAX (617) 726-5123, niklason@helix.mgh.harvard.edu
Tim Olson, Ph.D.
Assistant Professor Department of Mathematics,
University of Florida, 358 Little Hall, Gainesville, FL 32611 (352)
392-0281, FAX (352)392-8357, olson@totcon.com
Carey Priebe, Ph.D.
Assistant Professor, Department of Mathematical
Sciences, 104 Whitehead Hall, Johns Hopkins University, Baltimore, MD 21218
(410) 516-7200, FAX (410) 516-7459, cep@jhu.edu
Charles Putman, M.D.
Senior VP for Research Admin. and Policy, Professor of
Radiology and Medicine, Chair of ISWG lung imaging evaluation. Multi modality
lung imaging. Duke University, 012 Allen Building, Box 90026, Durham, NC
27708-0026 (919) 684-3403, FAX (919) 684-8525,
cputman@mail01.adm.duke.edu
Anthony P. Reeves, Ph.D.
Associate Professor School of Electrical
Engineering, 331 Rhodes Hall, Ithaca, NY 14853-5401 (607) 255-2342, FAX
(607) 255-9072, reeves@ee.cornell.edu
Harold S. Stone, Ph.D.
Fellow: NEC Research Institute, Princeton, NJ NEC
Research Institute, 4 Independence Way, Princeton, NJ 08540 (609) 951-2999,
(609) 951-2488, hstone@research.nj.nec.com
Ronald M. Summers, M.D., Ph.D.
Department of Radiology, National Institutes of Health,
Building 10, Room 1C660, 10 Center Drive MSC 1182, Bethesda, MD 20892-1182
(301) 496-7700, Fax: (301) 496-9933, rms@nih.gov
Raoul Tawel, Ph.D.
Jet Propulsion Laboratory, California Institute of
Technology, Mail 302-231, 4800 Oak Grove Drive, Pasadena, CA 91109 (818)
354-4951, FAX (818) 393-4272, raoul@neuron6.jpl.nasa.gov,
raoul@brain.jpl.nasa.gov
Yue Joseph Wang, Ph.D.
Assistant Professor of Radiology Electrical
Engineering, Computer Sci. & Radiology, The Catholic University of America,
Michigan Avenue 620, Washington, DC 20064 (202) 319-5879, lab (202)
319-5249, FAX (202) 319-5195, wang@pluto.ee.cua.edu
John B. Weaver, Ph.D.
Associate Professor of Radiology Department of
Diagnostic Radiology, Dartmouth-Hitchcock Medical Center, One Medical Center
Dr., Levanon, NH 03756-0001 (603) 650-5846, FAX (603) 650-5455,
John.B.Weaver@Hitchcock.ORG
B. Business Representatives.
James R. Aloise
Business Development Manager GE Corporate Research
and Development, Bldg. KW, Room C284C, P.O. Box 8, Schenectady, NY 12301
(518) 387-5068, FAX (518) 387-5449,
aloise@crd.ge.com
Nadeem Ishaque, Ph.D.
Manager, CT Program GE Corporate Research and
Development, Bldg. KW, Room C284C, P.O. Box 8, Schenectady, NY 12301 (518)
387-7603, FAX (518) 387-6030 , ishaque@crd.ge.com
John C. Huffman, Ph.D.
Director of Marketing, Medical Imaging MTS
Corporate R&D, Silicon Graphics, Mail Stop 005, 2011 N. Shoreline Blvd.,
Mountain View, CA 94043-1389 (415) 933-6037, FAX (415) 969-6289,
jhuffman@sgi.com
C. NCI Representatives
Daniel Sullivan, M.D. Associate Director,
Diagnostic Imaging Program (DIP) NCI, DCTD, DIP, 6130 Executive Blvd., Rm.
800, Rockville, MD 20852 (301) 496-9531, FAX (301) 480-5785,
sullivand@dtpepn.nci.nih.gov
Anne Menkins, Ph.D.
Program Director, Diagnostic Imaging Program (DIP)
NCI, DCTD, DIP, 6130 Executive Blvd., Rm. 800, Rockville, MD 20852 (301)
496-9531, FAX (301) 480-5785,
menkinsa@dtpepn.nci.nih.gov
Manuel Torres-Anjel, Ph.D.
Program Director, Diagnostic Imaging Program, National
Cancer Institute NCI, DCTD, DIP, EPN/800, 6130 Executive Blvd., MSC 7440,
Bethesda, MD 20892-7440 (301) 496-0735, FAX (301) 480-5785,
torresm@dtpepn.nci.nih.gov
Donald Henson, M.D.
Medical Officer, Division of Cancer Prevention,
National Cancer Institute NCI, DCPC, 6130 Executive Blvd., Rm. 330,
Rockville, MD 20852 (301) 496-9424, FAX (301) 496-8667,
deh@helix.nih.gov
D. Invited Presenters (unable to attend, reviewed
report)
James C. Bezdek, Ph.D.
Editor: IEEE Transactions on Fuzzy Logic Nystul
Professor of Computer Science, Computer Science Department, University of West
Florida Computer Science Department, University of West Florida, 11000
University Parkway, Pensacola, Florida 32514-5750 (850) 474-2784, FAX (850)
857-6056, jbezdek@argo.cs.uwf.edu
Ronald A. DeVore, Ph.D.
Professor, Department of Math & Statistics
University of South Carolina, Columbia, SC 29208 (803) 777-2632, FAX
(803) 777-3783, devore@oregano.math.scarolina.edu
David Donohoe,
Professor, Department of Statistics, Stanford
University Sequoia Hall, Stanford University, Stanford, CA 94305 (415)
723-3350, FAX (415) 725-8977,
donoho@playfair.stanford.edu
Heber McMahon
Professor of Radiology, University of Chicago, Chief of
Thoracic Imaging University of Chicago, Radiology Department, MC2026, 5841
S. Maryland Ave., Chicago, IL 60637 (773) 702-4532, FAX (773) 702-1161,
macm@midway.uchicago.edu
Michael W. Vannier, M.D.
Editor-in-Chief: IEEE Transactions on Medical Imaging
Department of Radiology, University of Iowa Hospitals & Clinics, 200
Hawkins Dr., 3966A JPP, Iowa City, IA 52242-1077 (319) 356-3372, FAX (319)
356-2220, michael-vannier@uiowa.edu
3. PRESENTATIONS AND
ABSTRACTS
| Monday, January 12, 1998, 8:00
a.m. - 5:00 p.m. |
| Co-Chairs:
Drs. Laurence P. Clarke and Carey Floyd |
| 1. Introduction and Overview of
Current Imaging Methods |
8:00-9:30
a.m. |
| 1. 1. Introduction
of Scope of Workshop (15 min.) |
Clarke |
|
The overall aims of the workshop will be
discussed. The intent is to use lung imaging as a clinical model for the
feasibility of technology transfer, and image processing as the technology
model. The technologies that were identified in the Rand Radius Data Base
will be summarized. The presenters were selected with funding from medical and
non-medical federal sources as indicated below. The intent of the workshop is to
first summarize the clinical rational for lung imaging and specifically lung
nodule detection (20 minute presentations, 15 minute discussion periods). We
will follow with short presentations of specific problems with current software
methods and representative software methods under development in the non-medical
sector that may be suitable for technology transfer (15 minute presentations, 15
minute discussion periods). The objective of the short presentations is to
stimulate focused discussion of appropriate software that may be transferred to
the medical imaging sector, suitable for lung imaging, and to discuss mechanisms
as to the best means for technology transfer. In view of the broad scope of the
technology being presented, it is not the intent to discuss in great detail
specific software methods, but to perform a general review and make
recommendations for software technology transfer. Please note that the extensive
discussion periods are considered critical for the outcome of the workshop. Both
35mm slide and overhead projectors will be available. |
|
1.2. Lung Cancer Imaging: Overview of
Clinical Requirements (20 min.) |
Putman |
|
Clinical overview of lung imaging and lung
nodule detection for the non-medical imaging scientists. Representative images
will be presented for different modalities such as chest X-ray imaging, X-ray
CT, PET and SPECT with discussion of the clinical problem with early detection
of cancer, diagnosis, and treatment. |
|
1.3. Clinical Overview of Lung Nodule
Detection Methods (20 min.) |
Freedman |
|
The role of the computer in enhancing the
detection of lung nodules in chest radiography will be discussed. Computer
controlled processing of digital chest images (including the use of neural
networks) is now routinely used in many sites around the world to enhance the
consistency of image quality for the human observer. The next step in this
evolution will be the routine application of computer aided detection methods to
digital chest radiograph interpretation. The potential methods of application of
Computer Assisted Diagnostic Methods (CADx) methods for lung nodule detection
will be reviewed in terms of both their clinical potential and problems
encountered in attempts at real world application. Emphasis will be placed on
those findings that interfere with the correct computer detection of lung
nodules and useful, or potentially useful, methods (including dual energy
methods) of compensating for these problems. An analogy will be made to breast
cancer detection and what would have to occur for chest radiography to become as
accepted and as useful in the detection of lung cancer as mammography is for the
detection of breast cancer. (Funded: ACS, U.S. Army, Agfa
Corporation) |
|
2. Feature Extraction, Lesion
Characterization and Classification in CAD |
10:00-11:30
a.m. |
|
2.1. X-ray CT: 3D Characterization of Lung
Nodules (15 min.) |
McNitt-Gray |
|
Approaches to the characterization of lung
nodules will be discussed. These would include nodule detection from volumetric
CT scans as well as tumor volume measurements, also made from volumetric CT
scans. Problems encountered with current methods and their clinical relevance
will be discussed. Similarly the need for new approaches and specifically, what
kind of expertise we could benefit from in future collaborative efforts will be
addressed. (Funded: NCI) |
|
2.2. X-ray CT: Lung Nodule: 3D Time
Related Changes (15 min.) |
Reeves |
|
The reliable detection and characterization of
small Solitary Pulmonary Nodules can be realized by using modern high resolution
helical CT scans and three-dimensional image processing techniques.
Three-dimensional techniques offer intrinsic advantages over conventional
two-dimensional methods. Robust segmentation is achieved by isotopically
resampling helical CT scans and then three-dimensional geometric filtering.
Changes in an SPN's size and shape over time are measured by comparing the
volume and other features obtained from two or more time separated scans. These
techniques result in robust quantitative feature measures of SPN's that can be
used to aid diagnosis. (Funded: NSF) |
|
2.3. Lung Nodule CAD Detection Methods
(15 min.) |
Giger |
|
Review of computer assisted diagnostic methods
(CAD) for lung imaging and specifically for lung nodule detection. Methods will
include (a) time related changes using difference image methods and, (b) use of
feature extraction and classification methods for lung nodule detection in chest
imaging and X-ray CT. (Funded: NCI, U.S. Army,
Whitaker) |
|
2.4. Feature Extraction: Adaptive and
Multi resolution Based Methods (15 min.) |
Clarke |
|
The use of adaptive computer assisted
diagnostic (CAD) modules will be described to potentially improve feature
extraction with emphasis on wavelet approaches These will include adaptive
methods for image noise suppression, adaptive selection of multi orientation
wavelet transforms for directional feature extraction, adaptive image
enhancement using Multi resolution wavelet transforms for improved segmentation
methods, and related possible filtering methods for rib cage and lung nodule
segmentation. (Funded NASA, DOD, NCI). |
|
2.5. Classification Methods: Fuzzy
Logic/ Evolutionary NN=s (15 min.) |
Fogel |
|
Computational intelligence techniques offer the
potential for assisting medical practitioners in detecting and diagnosing
features of interest. In particular, fuzzy logic and neural networks can serve
to facilitate nonlinear pattern recognition. Recent advances in evolutionary
computation indicate that optimal fuzzy/neural systems can be designed through
random variation and selection. Introductory examples of evolutionary fuzzy and
neural pattern clustering and classification will be described. (Funded: U.S.
Army). |
|
3. Multi modality: Image
Reconstruction and Image Restoration Methods |
12:30-2:30
p.m. |
|
3.1. Tomographic Reconstruction and
Restoration: Current Methods (20 min.) |
Floyd |
|
Recent developments in image reconstruction and
acquisition techniques have opened a new frontier for lung cancer imaging. The
recent development of large area flat panel radiographic image detectors,
combined with recent image reconstruction and restoration algorithms, offers the
promise of dramatic improvements in practical, cost-effective, three dimensional
imaging techniques for lung cancer screening. An historical overview of
tomographic imaging of the chest will be presented. Technical and algorithmic
requirements for tomosynthesis will be discussed in the context of the new
detector and computer developments. Image restoration will be discussed with a
focus on new techniques that potentially improve the detectability and
discrimination of pulmonary nodules both visually and with computer aids.
(Funded: NCI, U.S. Army) |
|
3.2. Limited Angle Tomography:
Tomosynthesis (15 min.) |
Niklason/GE |
|
Tomosynthesis is a method of obtaining
tomography images of an object from a limited number of projection images. The
recent introduction of flat full-field digital detectors with rapid image
read-out times may provide an opportunity to use tomosynthesis in chest imaging.
The potential advantages of this technique for chest imaging will be presented
along with our experience using tomosynthesis for breast imaging. Pulmonary
lesion detection and imaging of the airways are possible areas were
tomosynthesis may offer improvements over current projection images. Methods of
implementing chest tomosynthesis will be discussed including the required number
of projections, radiation dose, and total imaging time. (Funded:
GE) |
|
3.3. Localized Reconstruction and
Segmentation Using Raw Data (15 min.) |
Berenstein |
|
Newly found relationships between the Radon
transform and wavelet representation of images should lead to improvements in CT
imaging. First, it is possible to localize the data collection in CT, this may
lead to new techniques for lung imaging. Second, beyond the currently well
established usefulness of wavelets in image processing, it seems now possible to
do image processing using the "raw data" (the data acquired by the CT scanner)
which should have a better SNR and lead to sharper image segmentation and, thus,
better tumor detection. Comparison with other recent techniques of image
processing on CT scans will also be made. (Funded:
NSF). |
|
3.4. Limited Angle Tomography:
Stability of Non-Linear Inverse Problems (15 min.) |
Olson |
|
We will consider briefly some of the basic
ideas of stability from linear inverse problems, and try to understand how those
ideas are dramatically altered when trying to deal with nonlinear problems. We
will explore implications to severely ill-conditioned problems such as Limited
Angle Tomography. (Funded NSF,DOD) |
|
3.5. MRI: Adaptive Wavelet Encoding
Methods and Image Registration (15 min.) |
Weaver |
|
Registration is a crucial component of many
remote sensing and medical image interpretation applications: e.g., estimating
volumes of complicated structures and identifying changes between sequential
images. Warped registration is an important extension of rigid registration when
the view changes in remote sensing or the anatomy is in a different orientation
in medical imaging. The constraints used in warped registration determine the
properties of the warping. One method of warped registration matches structures
that are isolated with window functions and interpolates the mapping between
those structures. Two primary problems arise: eliminating the effects of the
window when matching isolated structures and stabilizing the matching procedure
for small structures while maintaining continuity. The use of adaptive MRI
wavelet encoding methods will also be reviewed. (Funded:
DARPA) |
|
4. Planar Image Registration and
Change Point Analysis |
3:00-4:00
p.m. |
|
4.1. Site Model Supported Registration
and Change Point Analysis (15 min.) |
Wang |
|
The detection and tracking of lesions from
image taken over a period of time and of the changes in shape and size of
lesions can provide vital clues for pattern analysis and classification. The
unchanged lesions represent a group with much lower potential of being cancer.
We discuss the possible application of site model supported registration and
change monitoring to developing an automatic cancer detection system. The site
model contains the locations of ROIs and the associate auxiliary information of
the patient. Each image of available image sequence will be registered to the
site model such that images taken from different views, using different sensor
modalities, and at different times, can be easily and efficiently compared. The
change monitoring can then be accomplished by difference information from
multiple images and usage of knowledge of human experts. Particularly the
existing side model of the patient can be used to detect the most relevant
changes in the newly acquired image to verify if any significant changes have
taken place. (Funded: U.S. Army, DOD, Whitaker) |
|
4.2. Statistical Techniques: Change
Point Analysis (15 min.) |
Preibe |
|
The detection and identification of change
points or regions of interest is a common goal in image analysis. One approach
involves the use of spatial scan statistics. A difficulty arises due to
competing concerns: small scan windows are required for potentially small
anomalies while larger scan windows are necessary to improve the accuracy of the
analysis. When the scan statistics are mixture model density estimates, a
borrowed strength profile likelihood approach can be shown to be superior to
standard joint likelihood estimation. This result will be presented and examples
including the application to digital mammography and the identification of
regions of interest in unmanned aerial vehicle imagery will be considered.
(Funded: DOD) |
|
4.3. Image Registration: Wavelet Methods (15
min.) |
Stone |
|
This talk covers the principles involved in
wavelet-based image registration. The idea is to use low-resolution wavelets of
images for registration, and progressively refine the results to obtain
registration of the full-resolution images. A resolution reduction by a factor
of N speeds up the registration process by about a factor of N square (in the
pixel domain) or more if Fourier techniques are used as well. When images differ
by pure translation, the techniques work very well for low-pass subbands, and
are useful but less reliable for high-pass subbands. The ideas extend as well to
rotations and rescalings, although each of these mappings introduce distortion
that reduces registration precision. (Funded DOD) |
|
5. Hardware Implementation
|
4:00-5:-00
p.m. |
|
5.1. Programmable VLSI:
Wavelets/NN=s (15 min.) |
Tawel |
|
The implementation of computer assisted
diagnostic (CAD) techniques for cancer imaging has enabled the development and
use of sophisticated image processing algorithms for feature extraction and data
mining in 2D and 3D digital image data sets. However, these image processing
applications are inherently computationally demanding due to the repetitive
nature of the underlying signal processing algorithm. Hardware based
implementation and deployment of such custom algorithms on FPGA based
reconfigurable hardware has enabled a hundred fold speed-up in computational
throughput over existing state-of-the-art computer workstations. This has
enabled for the first time real-time data processing and visualization on a high
performance generic platform. Current work on the implementation of neural
networks and the wavelet transform for image segmentation will be discussed.
(Funded: NASA, NSF) |
|
5.2. Advanced Workstation Approaches
(15 min.) |
Huffman |
|
With the current trend in medical imaging to
switch from the traditional analog formats to digital, there are numerous signal
processing methods which can be utilized. Scalable database representations and
adaptive signal processing methods can be used for efficient storage,
distribution, and computer-aided diagnosis using modality dependent criteria.
This presentation will describe some of the work going on at SGI and the medical
industry to incorporate these methods into clinical systems. (Funded:
SGI) |
|
6. DARPA: Representative Image
Processing Applications of Dual Use Technology (15
min.) |
Healy |
|
To be completed. (Funded:
DARPA) |
|
|
Tuesday, January 13, 1998, 8:00 a.m. - 12:00
p.m.
|
|
7. Summary of Workshop: Floyd
|
9:00-10:00 a.m. |
|
7.2. Discussion and Recommendations:
Science |
10:00-11:00 a.m. |
| 7.3. Methods for
Technology Transfer |
11:00
a.m.-12:00 p.m. | |