While U.S. providers focus on screening asymptomatic patients, in the Nordic countries VC has attracted attention primarily for detecting symptomatic colon cancer.
"Taking into account that colorectal cancer and its prevention are major challenges to medical society, any change of direction in the way of diagnosing colorectal polyps and cancer could have considerable impact on the healthcare system," wrote Dr. Valeria Fisichella and Dr. Mikael Hellström from Sahlgrenska University Hospital and Göteborg University in Göteborg, Sweden (Acta Radiologica, April 2006, Vol. 47:3, pp. 231-237).
"Thus, the wide implementation of (VC) in routine clinical healthcare would affect not just the daily work routines in radiology departments, but also strategies for future investments in radiological equipment, and indirectly also the selection of patients for conventional colonoscopy," they stated.
The study, based on a structured questionnaire mailed to all radiology departments in Sweden in May 2004, sought to determine the availability of VC and the reasons for its implementation or lack thereof, as well as indications, technical performance, and opinions on the procedure. Limited follow-up was conducted by telephone in June 2005.
The questionnaire was divided into three parts, including a general section about the total number of radiological exams performed each year and the availability of colonoscopy, barium enema, and VC. Departments that did not perform VC were asked to explain why. Those that did were asked to detail their methods and procedures.
The response rate was 83% (99 of 119) of the mailed questionnaires. Virtual colonoscopy was offered in 23 departments (23.2%). Barium enema and conventional colonoscopy were locally available in 89% of the cases, and were performed in nearly all hospitals that offered VC.
Of the 76 departments that did not perform VC, 30 (39.5%) intended to start in the near future. Larger centers offered VC more commonly than smaller ones.
"These departments did more (p < 0.001) radiological examinations annually (66,179 ± 37,807) than departments not intending to start a (VC) service (mean 30,489 ± 27,885)," the group wrote. Reasons for not implementing VC included the following:
- Lack of VC training and expertise: 34 of 73 (46.6%)
- Nonavailability of MDCT scanner: 33 of 73 (45.2%)
- Nonavailability of appropriate software: 31 of 73 (42.5%)
- Lack of physician time: 28 of 73 (38.4%)
- Awaiting further scientific documentation: 19 of 73 (26.0%)
- Limited CT lab capacity: 17 of 73 (23.3%)
- Nonavailability of spiral CT scanner: 13 of 73 (17.8%)
- Nonavailability of appropriate workstation: 13 of 73 (17.8%)
- Not economically motivated: 4 of 73 (5.5%)
- Not medically motivated: 2 of 73 (2.7%)
In contrast to the situation in the U.S., where the lack of reimbursement is cited as a key factor preventing widespread adoption of the exam, the decision to perform virtual colonoscopy in Sweden is not affected by the availability of funding.
"As long as the referring doctor is acknowledged by the general health insurance system, he or she can spend his or her money on any type of radiological imaging, including new techniques such as CT colonography (virtual colonoscopy)," Fisichella explained in an e-mail to AuntMinnie.com. "Referring doctors are cost-conscious, but it appears that the added (benefits) of CT colonography are well appreciated."
There is little doubt of VC's superiority to the barium enema exam. Of the 99 responding departments, 55 (55.6%) said that VC would "Yes, absolutely" or "Yes, probably replace barium enema" in the future.
Of the 23 departments that performed VC, eight (34.8%) did less than one exam per month, five (21.7%) did one to four exams per month, five (21.7%) did one to two per week, three (13%) did three to five per week, and two (8.7%) did more than five exams per week.
Among the busier centers, one department had performed a total of 51-100 VC exams, five departments did 101-200 total VC exams, and four departments more than 200 exams. In 1994, 10 departments performing VC had a 16-slice scanner, four departments used eight-slice MDCT, eight had four-slice MDCT, and one had a single-slice machine.
The most popular bowel prep approach was Phospho-soda (Fleet Pharmaceuticals, Lynchburg, VA) (47.8%) followed distantly by polyethylene glycol (13%).
Indications for VC included difficulty performing optical colonoscopy or barium enema because of old age or physical disability for 55.6% of the departments, incomplete colonoscopy for 33.3%, incomplete barium enema for 22.2%, and as an alternative exam regardless of history for 22.2%.
As for interpretation method, primary 2D interpretation with 3D endoluminal problem-solving was the rule in 60.9% of the centers, while the opposite was the protocol in 4.3%. Both methods were used for primary review in 34.8% of departments. All used collimation less than 3 mm, and all acquired images with subjects in both prone and supine positions.
The centers that promised to start a program had mixed results in achieving this goal. "Of the 30 departments that in 2004 ... had intended to start a (VC) service in the near future, nine (30%) had done so by June 2005," the authors wrote. "Most, however, had very limited experience, since less than half performed (VC) on a weekly basis.... This highlights the need for education in (VC)."
In fact, secondary to the lack of MDCT scanners, a lack of VC training and expertise was cited as the principal reason for nonimplementation.
"Unlike many other new applications of CT, (VC) includes several technical and interpretive aspects not previously handled by most radiologists," the authors noted. "For example, viewing the colon in an endoluminal perspective or in unusual cut planes and handling complicated software requires new anatomical knowledge and technical skill," and several studies have highlighted the importance of training.
The high number of centers awaiting further documentation (26%) may reflect the widely varying results seen in large published studies to date, the group wrote.
"This survey shows a relatively limited diffusion of (VC) in Sweden, mainly due to the lack of radiological training, along with limited multidetector CT scanner and software availability," the team wrote.
Regarding feedback since the survey was completed last June, "we have the impression that (VC) is taking on further, parallel to the continuing replacement of single-slice CT with multislice CT equipment over the country," Fisichella wrote in her e-mail.
By Eric Barnes
AuntMinnie.com staff writer
May 8, 2006
Tagged VC succeeds where colonoscopy fails in elderly, March 28, 2006
Two new VC trials under way in Europe, November 22, 2006
VC safe, surveys show, but not without incident, October 18, 2005
Best preps are tailored to VC reading method, November 16, 2005
Screening colonoscopy worthwhile into the eighth and ninth decades, September 1, 2003
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