It's feasible to perform virtual colonoscopy scans at remote health centers and have images transmitted via teleradiology to a central location where they are interpreted by radiologists, according to a study published in the November issue of the American Journal of Roentgenology.
The finding could improve efforts to boost compliance with colon screening guidelines, especially among Native American populations, and could have important implications in the ongoing struggle between virtual colonoscopy, also known as CT colonography (CTC), and the gold standard, optical colonoscopy, which must be performed onsite by an experienced gastroenterologist.
In the new study, virtual colonoscopy scans were performed by radiologic technologists at two rural medical centers serving a Native American population: Fort Defiance Indian Hospital in Fort Defiance, AZ, and Tuba City Regional Health Care Center in Tuba City, AZ. This population is seeing rising incidence and mortality rates of colorectal cancer, but their screening rates lag the general U.S. population, the authors said.
Radiologists at the University of Arizona in Tucson already interpret general imaging exams from both facilities via teleradiology link over a virtual private network. A research team led by Arnold C. Friedman, MD, wanted to see if they could extend their service to include virtual colonoscopy.
The RTs received brief onsite instruction, including performing a VC exam on a volunteer using a low-dose technique. The study covered exams performed between May 2008 and June 2009, with scans performed on 16- and 32-detector-row scanners.
A total of 321 virtual colonoscopy exams were performed, of which 87% were referrals for screening exams. Studies were transferred to the University of Arizona Hospital for interpretation.
Overall, 92% of patients (295/321) had acceptable amounts of residual stool, 91% (293/321) had acceptable levels of fluid, and 92% (294/321) had acceptable distention, the authors said. Of the study group, 14% (44/321) had polyps 6 mm or larger in size, the polyp size range that should get follow-up or intervention under current practice. The studies had a positive predictive value of 41% for those who subsequently underwent colonoscopy/polypectomy.
The study's results indicate that VC can be introduced and performed adequately in rural communities, with images interpreted remotely. Friedman said. However, he noted that remote VC implementation plans must include technologist training, education of referring physicians, careful attention to image transmission, and "clearly defined methods of communication with patients and referring providers."
The remote virtual colonoscopy service continues to operate, Friedman said; indeed, one site discontinued its teleradiology relationship with the university for general imaging studies but chose to continue with the VC service, indicating its value.
"Optical colonoscopy in many rural areas is limited," Friedman said. "Availability of CTC permits access to a robust method of colorectal screening for rural patients."
By Brian Casey
AuntMinnie.com staff writer
October 21, 2010
Related Reading
VC helps screen U.S. minorities, May 04, 2010
Hispanics have less access to colon screening, April 12, 2010
Colorectal cancer attitudes vary by ethnicity, August 26, 2009
Most primary care doctors discuss only some colon cancer screening methods, July 20, 2009
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