|Viratronix makes the V3D Colon. According to the manufacturer, expert readers can make a diagnosis in about 8 minutes and an average reader in 10 to 15 minutes.|
With an increasing number of Americans entering their 50s, there will be a need to screen them for the diseases of old age. But one screening examination for a disease that has a near-perfect cure rate has not caught on despite media campaigns and appeals by trusted celebrities. The colonoscopy is one exam that is both universally dreaded and avoided by those over 50. According to statistics from Viatronix, the manufacturer of the V3D Colon, the negative image associated with colonoscopies has caused between 80% and 85% of the population to never have a colonoscopy. Other sources put this at a far lower avoidance rate, but there is agreement that too few have had this key screening examination.
The two stumbling blocks to getting patients in the door have been the invasiveness of the examination, which includes the need for sedation, and the preparation, which involves patients having to cleanse their bowels with a combination of laxatives and fasting, and the need to drink a marking agent.
Part of this problem has been solved by the introduction of CT colonography, which is less invasive, faster, and cheaper than traditional colonoscopy.
Accurate and Inexpensive
For Anno Graser, MD, a radiologist at the Klinikum Grosshadern, Munich, CT colonography has been a boon to his practice. Since 2003, he has used the Siemens Medical Solutions’ syngo Colonography Polyp Enhanced Viewing (PEV) system to screen his patients.
According to Graser, CT colonography is very accurate. He cites a recent study that found 90% to 95% of polyps were found by expert readers (a rate equivalent to that of traditional colonoscopy); less expert readers found between 75% and 95% of polyps. “That is a huge step forward,” he said. The study participants read images that all had polyps. He adds that the computer system’s CAD will typically find about 90% of the large polyps. In about 90% of colonography and colonoscopy screenings, there are no significant findings.
|The V3D Colon also has a CAD that helps readers identify areas they may have missed.|
Graser points to the CT’s 64-slice capability as one of its biggest selling points in terms of accuracy. “In order to get a good image ? you need the best spatial relationships,” he said. He also notes that the system’s CAD is approved by the FDA.
Karen Horton, MD, associate professor of radiology at Johns Hopkins University, Baltimore, uses the CAD as a kind of second set of eyes. “I like it and usually run it in the background as a kind second read,” she said. “I do [a better job] with it on.”
The choice to use the syngo was a natural for Horton. “We have always had Siemens scanners,” she said. The university has the system set up on three of its radiology workstations. Two of the workstations are in a centralized reading room with the third in the same room as the university’s best CT scanner.
The test is also significantly cheaper than traditional colonoscopy. “Colonoscopy is much more expensive [in part] because of the sedation,” Graser said. “In the long term, colonography is about 35% cheaper than colonoscopy screening.”
Learning how to use the syngo is fairly easy. Graser said that the benchmark for basic competency is about 50 cases. Expertise continues to improve as more cases are read. The Klinikum Grosshadern does about 100 CT colonography examinations per day. It has the test set up on three of its scanners.
John Phelps, product manager-oncology for Siemens Medical Solutions, notes that “ease of use is very key” in the success of the product, adding that the tech-savviness of a physician is a factor in how easy it is to learn to use, with more computer-savvy radiologists being a little faster in learning the system.
The company offers both on-site and off-site training. Off-site training takes place in a classroom and hands-on setting. Siemens also sets workstations at key reference sites for fellowship training. The clinical classes use the workstations in training the radiologists about the use of CT colonography. The company also offers some Web-based training.
Part of what makes the system easy to use is that it runs on Microsoft XP. This means that most users find the system to be very intuitive. “There are a lot of drop-down menus and layering of tabs,” Phelps said.
Because the system is designed to handle multiple modalities, the workstations can be centralized. And even if a radiology department prefers to have a decentralized system, footprint demands are low, with the workstation about the size of a home computer.
The company also regularly updates the software a few times per year to add new features and functionality. “The upgrades have been excellent,” Horton said. “They’re easy to use and intuitive. The company is very supportive of feedback. They take it to heart, and they’re interested in incorporating it into the next version.”
Graser said that the system is very stable and reliable. “No machine is perfect, but last year we only were down half a day,” he said.
Though the syngo platform is reliable and regularly updated, Siemens does offer support for the system in those rare instances when it goes down. The support is offered 24 hours per day, with specific application support available from 8 am to 8 pm, including the capability to provide some remote diagnostic services.
The syngo platform is primarily sold to radiology groups in hospitals, academic settings, and medium to large radiology groups.
The syngo is not the only system on the market right now. The V3D Colon from Viatronix, which has been on the market since 2000, is another option.
Setting the Bar
Garrett Andersen, MD, director of virtual colonography at South Texas Radiology, San Antonio, has been using the Viatronix V3D Colon since 2005. He said that for him, its benefit is simple: “I like to read in three dimensions instead of two dimensions,” he said. “And it [is more] sensitive to smaller polyps.”
One of Andersen’s favorite features is the ability to do a “fly-through” of the colon. “I try to read three dimensions primarily, and most other products don’t have the fly-through capability,” he said. With this feature, it allows Andersen to look under folds in the colon. The initial data is presented in two dimensions, and then is translated into three dimensions in about 3 to 5 minutes with a centerline.
According to Zaffar Hayat, president of Viatronix, there are other features that make the product different. “It has clinical validation,” he said. “When we were designing it, we talked to the end users. It is very easy to read a study. An expert reader can make a diagnosis in about 8 minutes; an average reader in 10 to 15 minutes.”
The system also has a CAD that helps readers identify areas that they may have missed. The CAD marks these areas with yellow arrows in relation to the green centerline. The system also has a feature that measures the distance of the polyp from the rectum.
The V3D Colon originally began as a self-contained workstation. That has changed, with the system available also as a software-only package, which is compatible with PACS. About 50% of the company’s customers now just use the software. The only system requirements are a dual processor and two disk drives.
Andersen’s group has the entire workstation, but it is his understanding that another portion of the practice is in the process of purchasing the software-only package.
The viewer and workstation option is built on an HP platform. Viatronix has a contract with HP in which hardware problems are dealt with by HP within 4 hours. “For convenience, we use HP,” Hayat said. Viatronix will provide other hardware options if that is what the customer prefers.
The company also supports its software remotely. If the site is having a problem, Viatronix technicians will access the computer system and work to fix the problem. The first year of support is part of the purchase price.
If it makes a software update, Viatronix calls its sites and schedules the remote upgrade. In that way, it will not cause the radiology site to have interruptions in service.
Andersen is almost as impressed by the product’s service as its features. “It’s as good as any I’ve ever seen. They seem to be available day and night,” he said.
While the software and workstations have proven popular with clinicians, virtual colonography has also been a hit with patients.
Advantages Over Colonoscopy
There are several advantages for patients with virtual colonography, chief among them that there is no need for sedation. This is due to the fact that the examination is noninvasive.
Patients do experience some discomfort, but it is only for a few minutes. The discomfort is caused by pumping either CO2 or oxygen into the patient’s abdomen, distending it. The gas is released once the examination is finished.
CT colonography has proven popular with patients, particularly those who have experienced traditional colonoscopy. “We always hand out a questionnaire to [our patients], and those who have had both prefer not having sedation,” Graser said.
Since there is no sedation and the examination takes about 10 minutes to complete, patients typically can have it before they go to work and know that they will not experience any side effects. “When you’re done, you’re done,” Horton said. “It’s a very good test and better tolerated than colonoscopy.”
Though the examination is better tolerated by patients, Graser does not see it as a replacement for colonoscopy. “It’s my personal opinion that we can’t get rid of colonoscopy,” he said. Instead, he foresees colonography as the first screening step in the war on colon cancer, with those cleared being scheduled for a return visit a decade later and those who have a finding followed up with traditional colonoscopy. However, there is one major stumbling block: Colonography is currently not reimbursable.
Currently, there are only isolated cases of insurance companies reimbursing for CT colonography. In most cases, this is because the patient cannot tolerate a colonoscopy, has had a failed colonoscopy, or is too frail. According to Hayat, there is an isolated case of a radiologist in Wisconsin (a Viatronix user) who was able to get universal reimbursement.
According to all of the interviewees for this article, the insurance industry is waiting for the results of the recently completed American College of Radiology Imaging Network (ACRIN) trial to make a decision on whether to reimburse for the examination, which costs about a third less than traditional colonoscopy. The trial, which began in 2005, enrolled more than 2,300 patients at 15 sites across the United States. The study participants had to be at least 50 years old, scheduled for a colonoscopy, and had not received a colonoscopy in the last 5 years. “The outcome of the trial could potentially affect reimbursement guidelines in the future,” said Siemens’ Phelps.
But there are other areas of health care that are slowly offering CT colonography as part of standard cancer-prevention care. Hayat said that Viatronix has worked closely with the US military for many years, including trials of several thousand service personnel. The results of the trials established both the accuracy—93.9% for polyps 10 mm and greater—and the efficacy of the screening. According to Hayat, the US Army offers V3D Colon as part of its early cancer-screening program and expects that it will gradually be adopted by the Veterans Administration as well.
Even with the rather inconsistent reimbursement picture, there is a small percentage of patients—about 10%—who are willing to pay for the procedure out of pocket.
But reimbursement is only one of the stumbling blocks for the wholesale adoption of CT colonography. The other is preparation for the examination.
Preparation for CT colonography is much the same as it is for traditional colonoscopy. At about noon the day before the examination, the patient has to cease eating, must take a laxative, and drink some contrast agent.
There is a hope that a prepless alternative to this tradition will be developed. “The Holy Grail is the prepless approach,” Andersen said.
There have been several studies on and advocates of the prepless approach. A recent study at the University Hospital of Essen, Germany, found that clinicians could detect 83% of adenomatous polyps of less than 5 mm using a prepless approach. The overall specificity was 90.2%. Another study in Belgium used a semi-prepless approach, with patients fasting and drinking some contrast agent.
While this may sound promising, Michael Macari, MD, an assistant professor of radiology at New York University Medical Center, is more cautious about seeing the prepless approach as an immediate answer.
Many of the prepless approaches use fecal tagging to electronically stool in the bowel from the examination results. However, Macari does not see this as an effective method. “At this point, there is no commercially available [system] that allows a completely prepless approach without missing something,” he said, adding that the V3D Colon comes closest. “The potential is there in the near future, but not right now.”
One of the biggest problems with the fecal tagging/prepless approach is that unusually shaped polyps, such as flat ones, can be missed.
Macari said that until a viable prepless approach is developed, physicians must sell preparation as a positive. “If you explain the importance of the prep that you’ll clean yourself out and feel better, [you’ll have better cooperation],” he said.
But reimbursement and patient reluctance to do the preparation are only two of the more obvious problems facing radiologists who want to add CT colonography to their practices. There is also the issue of turf.
Who Reads Anyway?
There is a move, similar to one in cardiology, in which gastroenterologists are trying to take hold of CT colonography as their own test. This is a mistake, Horton said. “With this test, you see more than the colon. You also see the abdominal, extra-colonic organs as well. In about 10% to 15% of cases, you see something outside the abdomen—an aneurysm or a mass on the kidney, for instance,” she said.
Having insurance companies give the green light for reimbursement is not enough to ensure that radiologists perform the test. “For this test to catch on, we have to have a radiologist do it,” Horton said. To that end, Johns Hopkins now trains its radiology fellows on how to do the examination.
Even when all of the elements finally align themselves, and CT colonography becomes the primary colorectal screening tool, it may still be difficult to get patients in the door.
Getting Patients in the Door
Graser has seen firsthand how difficult it is to get patients screened for colon cancer. In his native Germany, all patients 55 and older are eligible to receive free colonoscopies. However, only 3% to 4% actually do. To combat this, Graser spends March—colorectal cancer month—on a multimedia campaign via radio, television, and lectures to get the word out on the need for colorectal cancer screening. “We’ve gotten a lot of positive feedback,” he said.
Hayat said that Viatronix works with local groups and gastroenterologists about spreading the word about both the need for both colorectal screening and the efficacy of CT colonography.
Screening and early detection are the keys to preventing colon cancer, a disease that has a 91% cure rate when caught early. And CT colonography, with its low cost and high accuracy, and noninvasiveness, could be the means to saving more patients. “I love this exam,” Andersen said. “I don’t think anybody should die of colon cancer.”
C.A. Wolski is a contributing writer for Medical Imaging. For more information, contact .