Computed Tomographic Colonography (Virtual Colonoscopy)
A Multicenter Comparison With Standard Colonoscopy for Detection
of Colorectal Neoplasia
Peter B. Cotton, MD, FRCP, FRCS; Valerie L. Durkalski, PhD;
Benoit C. Pineau, MD, MSc (Epid); Yuko Y. Palesch, PhD; Patrick
D. Mauldin, PhD; Brenda Hoffman, MD; David J. Vining, MD; William
C. Small, MD; John Affronti, MD, MS; Douglas Rex, MD; Kenyon
K. Kopecky, MD; Susan Ackerman, MD; J. Steven Burdick, MD; Cecelia
Brewington, MD; Mary A. Turner, MD; Alvin Zfass, MD; Andrew
R. Wright, MBBS; Revathy B. Iyer, MD; Patrick Lynch, MD; Michael
V. Sivak, MD; Harold Butler, MD
Context Conventional colonoscopy is the best available
method for detection of colorectal cancer; however, it is invasive
and not without risk. Computed tomographic colonography (CTC),
also known as virtual colonoscopy, has been reported to be reasonably
accurate in the diagnosis of colorectal neoplasia in studies
performed at expert centers.
Objective To assess the accuracy of CTC in a large number
of participants across multiple centers.
Design, Setting, and Participants A nonrandomized, evaluator-blinded,
noninferiority study design of 615 participants aged 50 years
or older who were referred for routine, clinically indicated
colonoscopy in 9 major hospital centers between April 17, 2000,
and October 3, 2001. The CTC was performed by using multislice
scanners immediately before standard colonoscopy; findings at
colonoscopy were reported before and after segmental unblinding
to the CTC results.
Main Outcome Measures The sensitivity and specificity
of CTC and conventional colonoscopy in detecting participants
with lesions sized at least 6 mm. Secondary outcomes included
detection of all lesions, detection of advanced lesions, possible
technical confounders, participant preferences, and evidence
for increasing accuracy with experience.
Results A total of 827 lesions were detected in 308 of
600 participants who underwent both procedures; 104 participants
had lesions sized at least 6 mm. The sensitivity of CTC for
detecting participants with 1 or more lesions sized at least
6 mm was 39.0% (95% confidence interval [CI], 29.6%-48.4%) and
for lesions sized at least 10 mm, it was 55.0% (95% CI, 39.9%-70.0%).
These results were significantly lower than those for conventional
colonoscopy, with sensitivities of 99.0% (95% CI, 97.1%->99.9%)
and 100%, respectively. A total of 496 participants were without
any lesion sized at least 6 mm. The specificity of CTC and conventional
colonoscopy for detecting participants without any lesion sized
at least 6 mm was 90.5% (95% CI, 87.9%-93.1%) and 100%, respectively,
and without lesions sized at least 10 mm, 96.0% (95% CI, 94.3%-97.6%)
and 100%, respectively. Computed tomographic colonography missed
2 of 8 cancers. The accuracy of CTC varied considerably between
centers and did not improve as the study progressed. Participants
expressed no clear preference for either technique.
Conclusions Computed tomographic colonography by these
methods is not yet ready for widespread clinical application.
Techniques and training need to be improved.
Author Affiliations: Department of Gastroenterology (Drs Cotton
and Hoffman) and Radiology (Dr Ackerman), The Digestive Disease
Center, and Department of Pharmacy and Clinical Sciences (Dr
Mauldin), and The Clinical Innovation Group (Drs Durkalski and
Palesch), Medical University of South Carolina, Charleston;
Departments of Gastroenterology (Dr Pineau) and Radiology (Dr
Vining), Wake Forest University School of Medicine, Winston-Salem,
NC; Departments of Radiology (Dr Small) and Gastroenterology
(Dr Affronti), Emory University Hospital, Atlanta, Ga; Departments
of Gastroenterology (Dr Rex) and Radiology (Dr Kopecky), Indiana
University Hospital, Indianapolis; Departments of Gastroenterology
(Dr Burdick) and Radiology (Dr Brewington), University of Texas
Southwestern, Dallas; Departments of Radiology (Dr Turner) and
Gastroenterology (Dr Zfass), Virginia Commonwealth University
Medical Center, Medical College of Virginia, Richmond; Department
of Radiology, St Mary's Hospital, London, England (Dr Wright);
Departments of Radiology (Dr Iyer) and Gastroenterology (Dr
Lynch), M. D. Anderson Cancer Center, Houston, Tex; Departments
of Gastroenterology (Dr Sivak) and Radiology (Dr Butler), University
Hospitals of Cleveland, Cleveland, Ohio.