Screenshot from the Virtual Colonoscopy fly-through
FDA Approves 3-D Virtual Colonoscopy for Detection
of Colon Cancer
In a major step forward for the technology of "virtual
colonoscopy," in April, 2004, the U.S. Food and Drug
Administration announced approval of the use of a 3-D
computer visualization technology developed at Stony Brook
as a patient screening tool for detecting colon cancer,
including polyps, masses and other lesions. The technology,
licensed to start-up Viatronix,
Inc., a tenant company in the Long Island High Technology Incubator
on the University campus, is the first of the virtual
systems to obtain FDA approval. The decision presumably
reflected the results of a groundbreaking virtual
colonoscopy study published in the December, 2003, New
England Journal of Medicine and American
Journal of Roentgenology, which reported that the
new three-dimensional virtual colonoscopy detected about
94% of polyps larger than 8 millimeters, while some 90% of
polyps were detected by screening with the more invasive
conventional colonoscopy procedure.
The study, conducted by radiologists from Bethesda Naval Hospital,
Walter Reed Army Medical Center, and the National Cancer Institute,
reported the largest prospective evaluation to date of virtual colonoscopy
as a colorectal screening test, involving over a thousand asymptomatic
adults who were at average risk. A less favorable report,
subsequently published in the Journal
of the American Medical Association actually
covered an older study, completed more than two years ago, using
a 2-D virtual scanning technology. The contrasting reports were assessed
in a Wall
Street Journal article, "Tale of Two Studies: Cutting
Through Confusion on Virtual Colonoscopies," April 27, 2004.
The 3-D process is based on images constructed from a CT
scan, which requires a few minutes and no sedation, in
contrast to about one hour required -- with sedation
strongly advised -- for the conventional procedure.
The most important impact of the new diagnostic technology
may be to encourage patient compliance. Although the
procedure is recommended for everyone over age 50, and
colon cancer -- the second largest cause of cancer-related
death -- has a 92% cure rate if identified early, less than 40% of
Americans at risk for the disease seek out screening because they
say the procedure is unpleasant. An editorial in the same issue of
the NEJM concluded, "If
the results of this well-designed study are reproducible on a
wider scale, and if the important questions regarding the
appropriate size threshold and the surveillance of smaller
polyps can be resolved, then screening virtual colonoscopy
is ready for prime time."
A simulated fly-through showing full forward-backward, 360
degree point of view can be seen here. [Quicktime
plugin required]