by Dan Foster
Because the facility considering refurbished equipment is not likely to be considering the most recent 16-slice scanner (up to 38 images per second), I am limiting this discussion to dual-slice and quad-slice scanners. Multi-slice CT (MSCT) scanners seem to be about as hot as free Viagra"! in a retirement community, and there is no doubt that they are here to stay. So what is to become of the single-slice CT system? It has been postulated that MSCT will be the standard protocol by 2004. Just where does that leave the hundreds of small hospitals and imaging centers that are neither able to afford, nor justify, the cost of this newest technology? Perhaps the question better asked is, “Is MSCT required to provide accurate diagnosis and high-quality patient care?”
The answer to this question is a resounding, “No!” Of course, the three major OEM companies would have you believe that without MSCT you are not able to do the types of studies that your physicians demand. But, if MSCT is the only solution, why then do each of the Big Three offer only single-slice systems as part of their refurbished equipment offerings? Simple ... because single-slice helical CT is still a viable and significant diagnostic tool.
As sales manager for a major consulting company and remanufacturer of CT scanners (among other modalities), not a week goes by when I don’t receive at least one request for a multi-slice scanner. Occasionally the request is from a major hospital hoping to save a few hundred thousand by purchasing pre-owned, high-end equipment. But most often the request comes from a small to medium size facility that feels the need to have technology equivalent to their cross-town competitor.
MSCT first entered the scene just four years ago in 1998 (the Elcsint CT Twin and Imatron’s electron-bean scanner notwithstanding). A request for a refurbished system of this type is, by and large, unrealistic, if only by nature of the fact that very few pre-owned systems of recent vintage find their way to the secondary market. Additionally, the cost of acquisition, removal, transportation, staging and refurbishment, installation and warranty would be such that the savings realized over the purchase of a new system would be marginal at best. Facilities considering the purchase of MSCT on the used market need to seriously assess whether this technology is truly necessary for their needs and justified by their budget.
What, really, has been brought to the table with the advent of MSCT? Primarily the reduction of motion artifact, an increased capacity for patient throughput (and tube loading), and the potential for greater image quality. Healthcare providers that are not performing or anticipating 50 or more CT studies weekly should have no concern with throughput. It is not a factor. Motion artifact is a valid concern, but these same facilities need to evaluate what percentage of the studies they do is grossly affected by motion. If the majority of studies are done on pediatric or trauma patients, then MSCT should be seriously considered, and every effort should be made to purchase such a system. And as for improved quality, in axial mode, multi-slice systems produce about the same image quality as equivalent, single-slice systems.
The introduction of whole-body CT screening has been a predominant factor in the justification for MSCT systems. The three major components of total-body CT are coronary artery calcium scoring, low-dose lung scanning, and virtual colonoscopy (more accurately described as CT colonography). The jury is still out on the efficacy of low-dose lung scanning while clinical trials continue in the Early Lung Cancer Action Project (ELCAP). Likewise, there remains much dissention about the diagnostic usefulness of the information obtained about the pulmonary system during whole-body CT scanning. Still, the fact remains that some pathologies have been detected with lung screening, but not significantly more so by MSCT over single-slice technology.
Calcium (cardiac) scoring is regularly performed on single-slice scanners, with MSCT studies claiming greater exactitude. (The increase in accuracy is attributable to the fact that faster MSCT scan times can allow for a complete scan to be done in a single breath-hold.) But to date, only EBCT is accepted by some cardiologists, at any level, for coronary calcium testing; and the test still remains one of screening, rather than diagnostic, in nature. The purpose of calcium scoring is not to diagnose, after all, but to try to identify those asymptomatic individuals who may be at risk. Both single-slice and MSCT have a large percentage of false-positive results, but improvements in workstations and software will continue to improve the accuracy of findings, even for single-slice systems.
Of the components of whole-body CT scanning, CT colonography is, by far, the most widely accepted as a screening tool and the most useful from a diagnostic standpoint. Colorectal cancer is second only to lung cancer as a major killer in the U.S. , and that is largely because only about 40% of at-risk individuals are screened for colorectal disease by conventional methods. MSCT systems perform complete scans for CT colonography in a fraction of the time of a single-slice helical scanner, but greater, clinically significant, accuracy from MSCT has yet to be proven. Either method can detect growths as small as 5 mm. This is statistically valid in a cancer type that tends to have a lengthy, pre-clinical period of development. So important is the future of virtual colonoscopy that several companies now market workstations designed specifically for this type of study. Most recently, 3DMed has introduced the Rapidia™ workstation, a relatively low-cost, yet powerful, tool for the detection of colorectal cancer using single or multi-slice CT.
Low-dose lung studies have been underway since 1993 when single-slice helical CT was the only widely available tool, while it can be argued that coronary artery calcium scoring done on single-slice scanners is no less valid than screening done on MSCT when compared to the gold standard of EBCT. And for the only screening study done on CT that is likely to be reimbursable in the near future, CT colonography studies done on single-slice CT are as valid as those performed on MSCT and will be no less billable, thanks to the rapid processing times that today’s workstations provide for MPR studies and 3D volume rendered images. Further improvements in post-processing capabilities will magnify the utility of these workstations and help expand the role of single-slice CT in both diagnosis and treatment.
It should not go unmentioned that the vast majority of the literature touting MSCT comes out of large university teaching hospitals that are either subsidized (in their purchases of the equipment) by the major OEMs, or have the wherewithal to afford such cutting edge technology. However, these same institutions note problems inherent in the implementation of such technology, but these are brushed aside as if they are of no consequence. To the average healthcare provider, the consequences are substantial and costly. The problem is two-fold: veritable volumes of information need to be interpreted, and the deluge of data needs to be somehow easily archived and retrieved.
Dr. Brooke Jeffrey, Chief of Abdominal Imaging at Stanford University acknowledges that Stanford has invested in a PACS to archive and store images which, Jeffrey said, is just about essential with MSCT. With PACS thrown into the mix, the price tag for MSCT increases 20% or more (not to mention the cost of a PACS administrator). Dr. Michael Vannier, Professor of Radiology at the University of Iowa ( Iowa City ) has noted that, “When acquiring a new multi-slice CT scanner ... throw out all the old protocols and develop new protocols for everything.” This sounds like good advice, but not very practical, or cost-effective, for the facility that has and needs only a single CT.
Over the next couple of years, expect multi-slice CT scanners to become more available in the refurbished equipment market. Opportunities exist, now, that allow healthcare providers to purchase high-end, single-slice helical scanners today and upgrade to MSCT when it becomes more readily available. My company, for one, has a program whereby a buyer of, for example, a GE CT/i sub-second scanner can upgrade in a couple of years to multi-slice technology, and get full credit for the original cost of the CT/i toward the purchase of the newer system.
Single-slice CT scanners are not about to become obsolete if for no other reason than that the market for this generation of scanner remains considerably greater than that for MSCT. Even GE Medical Systems, the Borg of the medical community, still actively markets no less than four single-slice scanners (all produced off shore) that are part of its current CT products offering. And being new does not mean that these systems necessarily have improved capabilities over a properly remanufactured, five or six-year old scanner.
So take the time to assess your needs and your resources carefully before you begin the search for a replacement or new CT scanner. Know what types of studies you will be performing, learn what systems best suit your needs, and let that information be your guide for your purchase. And above all, compare, compare, compare.
Dan Foster has been active in the used equipment industry for over 12 years. He is currently Manager, Sales and New Product Development for MECS, Inc. of Brookfield , WI . MECS is an ISO 9002 certified remanufacturer of diagnostic imaging equipment specializing in GE products. Comments or questions regarding this article may be sent to dpfoster@mecsinc.com
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