Virtual Colonography: On the Brink

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CT colonography or virtual colonoscopy is far from a new procedure. In fact, CT colonography has been around since the late 1990s. Although the procedure seems to offer some advantages over conventional optical colonoscopy, adoption has been sluggish. Colorectal cancer is the second leading cause of cancer death in the U.S., and third most common cancer among men and women in the U.S. Yet, fewer than half of patients over age 50 comply with colorectal cancer screening guidelines. Some 90 percent of colon cancers occur over age 50.

Optical colonoscopy allows both the detection and removal of polyps, but it is invasive and requires bowel preparation, sedation and minor recovery time. On the other hand, virtual colonoscopy offers a minimally invasive alternative to polyp detection. Studies indicate many patients would prefer and comply with CT colonography over optical colonoscopy. CT colonography has a markedly lower risk of perforating the colon than conventional colonoscopy. What’s more, at $600 to $1,500 per study, the cost of the high-tech procedure can be comparable or lower than conventional colonoscopy. Still, utilization for virtual colonography sits at a mere 15 percent. But times are changing, and CT colonography appears poised for a breakthrough. Specifically, CT colonography should be reimbursable in the next two years. In the meantime, the cost runs between $400 and $800 per study.

Another game-changer could be the results expected soon of the largest multicenter research study to compare the effectiveness of the two technologies, being conducted by the American College of Radiology Imaging Network (ACRIN).


Ready for prime time

When CT colonography first became a clinical option, many facilities hesitated to rush into virtual colonoscopy because the technology did not seem ready for prime time, says David Kim, MD, assistant professor of abdominal imaging at University of Wisconsin Madison Health System.

The last several years have delivered improved techniques and software enhancements to make virtual colonoscopy more practical, easier to read, effective and comparable to optical colonoscopy. On the procedure side, fluid and fecal tagging makes it easier for readers to distinguish residual stool from polyps and the switch from room air to carbon dioxide allows uniform distension of the colon for better visualization. On the technology end, the advent of primary 3D display also simplifies polyp detection and aids workflow.


Reimbursement: The next barrier

Technology adoption is a multi-faceted process. Widespread adoption requires proof of clinical utility and adequate reimbursement. Currently, the primary barrier to widespread adoption of virtual colonography is on the payment side; the Centers for Medicare and Medicaid Services (CMS) do not mandate reimbursement for virtual colonoscopy. “Third-party payors and Medicare are being careful not to prematurely approve several of the rapidly developing new screening technologies, such as CT colonography,” explains Beth McFarland, MD, chair of the American College of Radiology (ACR) Colon Cancer Committee. The organizations look for clinical validation and standardization of a procedure prior to widespread reimbursement.

Currently, physicians must use category III CPT codes for virtual colonography. These “emerging technology” codes are not assigned value, which make CT colonography nonreimbursable in most cases. (CT colonography is covered locally in some instances, mainly in the case of a failed or incomplete optical colonoscopy.) In addition, a handful of patients do pay out of pocket. 

Reimbursement, however, is not the only hitch, says Judy Yee, MD, chief of radiology at San Francisco Veterans Administration Medical Center in California. The U.S. lacks a critical mass of radiologists trained in CT colonography, says Yee.

The next 12 to 18 months will deliver significant changes. CT colonography will shift from an emerging technology to an established procedure. One of the primary factors behind the shift is the expected release of the ACRIN II Trial results early this year. “ACRIN II should have a tremendous impact towards more generalizable validation,” says McFarland. Researchers announced results at several meetings this fall and shared that the 15-center trial demonstrates the diagnostic efficacy and interobserver consistency for clinically significant polyps. Other studies supporting screening CT colonography include the Italian IMPACT study and the Munich Colorectal Cancer Prevention trial. “In the next year or two, we’ll see a fundamental shift in how we screen for colon cancer in the country,” predicts Kim.


Toward CPT I

Category I CPT codes are the prerequisite for national Medicare reimbursement and often provide the framework for private coverage. The ACR is working toward CPT I status for virtual colonography, and positive results from ACRIN II and other studies should provide momentum. Yee predicts that virtual colonography could gain CPT I status in 2009. “Third-party payors are waiting for ACRIN II results. The trial should make a difference and impact colorectal cancer screening recommendations in average-risk adults,” explains Yee.

Other forces are gathering momentum as well. For example, Wyoming Congresswoman Barbara Cubin introduced H.R. 4879, the Virtual Screening for Cancer Act (VSCA) of 2007. The legislation is designed to increase access to virtual colonography and could lead to coverage through a National Coverage Decision (NCD). Regardless of the route, the writing is on the wall. Virtual colonography reimbursement should improve in the next 12 to 18 months. “The potential [virtual colonoscopy market] is huge. In the next 10 years, as many as 50 million Americans may need the exam,” notes Kim. Smart providers should get ready.


Laying the groundwork

Providers eyeing the virtual colonography market need to consider multiple factors as they prep for 2009 and beyond. “Training is the most important step a practice can take; readers need to develop facile skills with 2D and 3D image display review of datasets in the 800 to 1,000 image data range,” says McFarland. Training should cover both physicians new to virtual colonoscopy techniques and early adopters as more recent techniques have evolved in the last five years. For example, five years ago, virtual colonography studies did not tag stool, but today stool is tagged with barium or iodinated contrast.

Interested radiologists can find multiple training courses across the country via various professional societies, individual university programs and at a state-of-the-art on campus ACR training facility. The new ACR program opening in March pairs novel training software and various vendors’ 3D workstations to expose readers to different size and shapes of polyps, with individual tailored feedback. ACR practice guidelines deem a reader qualified after he or she interprets 50 colonoscopy-proven virtual colonoscopy studies.

Another major ingredient is technology. CT colonography requires a 16-slice or higher CT scanner, PACS and post-processing solution able to handle large datasets. Options include Barco Voxar 3D ColonMetrix, GE Healthcare CT Colonography Applications Package, TeraRecon Aquarius Workstation, Viatronix V3D-Colon and Vital Images Vitrea. Strong integration between the advanced visualization solution and PACS can benefit the practice as well by streamlining workflow. Colon CAD is another promising development, says Kim. Tools such as Medic-sight’s ColonCAD software and Siemens Medical Solutions syngo Colon-ography PEV can help inexperienced readers detect lesions.

Anno Graser, MD, lead researcher of abdominal imaging at University of Munich in Germany, adds to the CT colonography prerequisite list. Sites that want to establish a virtual colonography program should establish a solid patient protocol to provide reproducible quality data. An automated insuflator that uses carbon dioxide rather than room air provides better distension of the colon, says Graser. Finally, double reading or CAD can be worthwhile. “In the beginning, even experienced radiologists will miss lesions,” notes Graser. Solutions like Siemens syngo Colonography PEV accurately detect polyps in the 6 to 25 mm range and readily integrate into the review process. To date, virtual colonography can’t detect polyps smaller than 5 to 7 mm.

Yee recommends sites designate a virtual colonography program leader to oversee the implementation from training to referring physician education and marketing. In addition to physician training, a solid virtual colonography program hinges on training all staff involved in the screening program. “Schedulers, techs and nurses need to understand the specifics of virtual colonoscopy including bowel cleansing and colonic distensions.” In addition, sites can initiate a relationship with referring physicians by providing educational lectures and instructional sheets and collaborative case review.

Training is essential, says Kim, but the other component of a quality program centers on the creation of a virtual colonoscopy program rather than the simple addition of another procedure. A sound CT colonography program is akin to a mammography program. That is, one staff person assumes responsibility for patient follow-up and quality of care, so patient follow-up does not fall through the cracks. Specifically, the practice can generate letters to remind patients to schedule studies at the appropriate interval. Typically, virtual colonography studies are recommended at three-year intervals, as opposed to optical colonography exams that should be conducted every seven to 10 years, according to current guidelines.

Quality will be a key factor as virtual colonography hits the radiology mainstream. The ACR is currently piloting benchmark CTC quality metrics which will help track proper techniques, complications and key outcome metrics, says McFarland. Hopefully, these metrics will promote efficiency and quality of clinical practice and may, in time, provide a structure for pay for performance.


Going forward

“CT colonography will have a tremendous public health impact,” states Kim. “Virtual colonography is comparable to optical colonoscopy, and widespread adoption should help reduce the number of colorectal cancer deaths,” adds Graser.

The procedure is ready for prime time, and improved reimbursement is in the works. Prerequisites for entering the CT colonography arena include the ubiquitous 16-slice CT scanner, post-processing hardware and software, training for both radiologists and staff and a plan for establishing an ongoing screening/follow-up program.