Trial Results for Virtual Colonoscopy May Lead to Widespread Use

October 2, 2007

Preliminary results from the National CT Colonography Trial (ACRIN 6664) which included 2,531 participants throughout 15 U.S. centers, proved a 90% per-patient sensitivity for adenomatous colorectal lesions 1 cm or larger in diameter which is very closely equivalent to optical colonoscopy.

Colon cancer remains the second leading cause of cancer related deaths in the United States. Statistics show that less than one half of the 70 million people who are eligible to get screened actually do so. Hopefully, the results from this new trial will give patients a more comfortable alternative for colon screening compared to traditional optical colonoscopy which is somewhat invasive.

Virtual colonoscopy requires the same cleansing preparation as traditional colonoscopy, however once the patient is prepped and on the scanning table, the exam only takes 5-10 minutes with the patient being scanned in the prone, then the supine position. No sedation is required, so patients are able to return to work or normal activities immediately following the exam.

Previously, there were multi-center trial study results which ranged from a sensitivity of 94% and 96% to as low as 55% and 59%, for clinically significant polyps. The large variance in trial results were blamed mostly on poor study design and the lack of VC training. However, the ACRIN trial required VC readers to have read at least 500 cases or attend a 1.5 day training course, and all had to pass a certified exam in which they detected 90% of the adenomas 1 cm or larger in 50 cases.

Optical colonoscopy still has the advantage of being able to diagnose the patient, and concurrently removing polyps if necessary with their detection. However, the referral rate for polyp removals in the ACRIN trial participants was only 8.3%. Such a low referral rate suggests that VC will not be too expensive an alternative for routine use in colon cancer screening.

“I think the results show a remarkable amount of thoughtful effort” on the part of the researchers, commented Dr. Elizabeth McFarland, an associate professor of radiology at the Mallinckrodt Institute of Radiology at Washington University in St. Louis. What matters from this point forward is “how we disseminate this (modality) in a way that we maintain high standards and make it feasible for people to do out in the community,” she said.

“Let’s all agree that the validation phase is over, and let’s work on widespread screening,” commented Dr. Perry Pickhardt, an associate professor of radiology at the University of Wisconsin in Madison.”

About InView Medical Imaging
InView Medical Imaging is Fremont’s Premier diagnostic imaging center. Since it’s opening in 2005, we’ve quickly become the imaging center of choice for physicians and patients in the Fremont community and greater East Bay Area. InView Medical Imaging offers a range of imaging services, including MRI, CT, Ultrasound and Bone Density as well as procedures such as Biopsy Exams, Interventional Radiology Procedures and Radiofrequency Ablation.

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