Medical innovations, particularly those that clinicians can readily apply to the diagnostic process, generally receive considerable attention at the time of their introduction into the health care arena. This attention is often focused on the technical breakthrough achieved by the innovation. Indeed, incremental improvement in technical characteristics or performance in itself is considered by many radiologists to be an innovation, and the radiology community generally accepts or discards such innovation on the basis of measurable improvements in key technical characteristics, for example, resolution or zoom fidelity. After the excitement of a new innovation abates, it is generally adopted into the mainstream of diagnostic practice or discarded. More accurately, local or regional adoption follows and some radiologists embrace and utilize the innovation wholly or incrementally depending on many varied factors.

Some innovations continue to draw significant attention from radiologists and clinicians long after their introduction. These are generally major technological breakthroughs such as positron emission tomography (PET), computed tomography (CT) and magnetic resonance imaging (MRI). These major breakthroughs represent technical leaps that are easily combined with new clinical opportunities. Major innovations are not left unchanged; they are tweaked and continuously refined to further enhance their utility. Such continued refinement often leads to secondary and tertiary innovations centered about the initial breakthrough, as in the example of MRI. Not a week or month goes by without the introduction of a new acquisition sequence or regional coil. Many such innovations enhance our ability to detect disease but even more represent individual or institutional directives that are not widely applicable. From the technical and scientific perspective, these small innovations represent a version of the scientific method as it is applied to clinical conundrums. Those who continue to push the limits of existing technology with new technical refinements are basically asking and building more and more refined hypotheses concerning the technology. Is one sequence better than another? The hypothesis here is that one sequence is better, and data are collected to support the hypothesis. Similarly, is one surface coil better than another for detecting hepatic lesions? The hypothesis renders that one is better. And so back and forth goes the MR community until one best sequence or coil is defined and widely applicable for a specific problem for a set period of time. There is nothing wrong with this process, and it has served the radiology community well.

Although many new innovations have emerged from this process of refining and extending the use of imaging technology, the current economic environment begs a question: When do payors stop reimbursement for the incremental improvement in a major imaging technology? Or, put another way, does a 0.1-mm resolution enhancement justify an extra $200 for an imaging study, and should Blue Cross/Blue Shield or the Health Care Financing Administration (HCFA) reimburse it? This is a daunting question for the radiology community at large, and for those specifically involved in innovation. It focuses the need for technical clarity against the requirement of limited resources and budget neutrality.

MultiSlice CT Scanners

One of the latest entries in the radiology marketplace is the multislice CT scanner, introduced by a number of manufacturers in 1998. A multislice, multidetector system reduces body imaging times to less than 20 seconds while achieving multiplanar imaging resolution of 0.25 mm. With further enhancements such as zoom upgrades, multislice, slip-ring CT scanning can be completed 8 to 24 times faster than helical CT, resulting in acquisition times of 0.25 to 0.5 seconds. Using adaptive array detector systems also permits the acquisition of thinner slices, down to 0.5 mm, and the ability to simultaneously reconstruct images to produce real-time imaging that is useful for interventional procedures.

The potential applications of this innovation abound. Some early proponents of the technology have emphasized its application in trauma and with critically ill patients. Any imaging tool that offers useful imaging characteristics and rapid acquisition clearly will benefit patients who cannot cooperate. Life-threatening injuries can be identified more quickly by emergency department physicians as a result of swifter image acquisition. Internal injuries in trauma patients that are identified and treated within the initial golden hour following injury are more likely to result in improved survival and lessened disability. Although patients brought to trauma centers during this interval may also be diagnosed, it is the high resolution and ability to perform repeated slicing that is an especially useful feature of multislice CT. A typical motor vehicle accident patient requires images of the chest/abdomen/pelvis, which a single-slice CT scanner can perform in 2 to 3 minutes. The same examination can be performed by a multislice CT scanner in less than 20 seconds, and multiple images can be acquired of areas of interest in an equally short interval. The additional images may yield valuable information, which can be quickly acted on by the clinical team. Early adopters of this innovation consequently have seen many uses for it in trauma and emergency situations.

Early adopters also are intrigued by the three-dimensional images rendered by the multislice CT because of their potential application in surgical planning. Surgeons are able to review anatomic associations, for example, vessel architecture, in great detail before surgery. This is especially important in organ transplantation and interventional procedures such as cryoablation. Some multislice CT protocols are also being evaluated for their use in the early detection of colorectal carcinoma. Colonoscopy remains the gold standard for visualizing suspicious polyps early in their development or malignant transformation, but it is quite uncomfortable for patients and requires 15 to 30 minutes to perform. Multislice CT can eliminate the discomfort and reduce the examination to a few minutes. These features are particularly important in high-risk patients who require regular examinations.

Other applications include the diagnosis of life-threatening pulmonary embolism. Current scintigraphic techniques are highly accurate but require at least one hour to complete. Direct visualization of anatomic detail concerning the size and location of an embolism cannot be achieved by scintigraphy, so a need exists for a rapid, high-resolution imaging technique in this setting. Despite some improvement in lesion localization offered by helical CT, most peripheral emboli cannot be detected by this latter technique. Consequently, careful attention will have to be given to multislice CT for the diagnosis of pulmonary embolic disease. Virtually any pulmonary or cardiac condition that is accompanied by specific windowing or gating limitations due to organ motion will likely be imaged more clearly with multislice CT because of the extremely short acquisition times involved. Cardiac applications have focused on the technique’s ability to detect coronary artery calcifications better than electron beam CT. The imaging of particularly small structures, for instance, inner ear or spinal cord abnormalities, likewise could be performed more accurately with multislice CT.

From the patient perspective, multislice scanners boast increased comfort as well as accuracy. Patients require less time in the scanning suite and breath holds can be curtailed. In addition, technicians likely will find the new scanners easier to operate because their system architecture permits thinner or thicker slice acquisition without the need for patient rescanning. The CT scanner tubes also have a longer half-life, thereby reducing scanner downtime and patient rescheduling. For emergency department requirements, the rapidity of scanning results in more opportunities for add-on cases during the day or evening without disruption of the workflow in the radiology department.

Once again, multislice CT scanners appear to follow the classical path of innovation in that they represent tertiary innovations associated with the introduction of CT some 30 years ago. There is little doubt that multislice CT is in its infancy and will require additional investigation to prove its diagnostic utility with some certainty. However, there is also little doubt that the scanner will be more expensive or that the imaging studies generated will cost more to attempt to recoup some of the hardware investment associated with the purchase of such a scanner or upgrade. Multislice CT scanners cost an estimated one third to one half more than single-slice CT scanners. But will payors appreciate and assign value to the contribution of this innovation enough to pay more for it? Will enhanced patient throughput, owing to faster acquisition time, augment revenue sufficiently enough to pay for the capital purchase? Will this innovation be unique enough to require its own HCPCS (HCFA Common Procedures Coding System) or other revenue code?

Cost-to-Value Relationships

The decisive question here clearly is whether or not the information garnered from the multislice CT scanner reduces short- and long-term downstream costs to the payor. If it does, it will likely be viewed as a valuable technology; if it does not, it will be reimbursed at the same level as single-slice or helical CT. The accompanying schema outlines the path necessary to illustrate the value of multislice CT from a payor perspective (figure 1).

Value exists in health care delivery where an unmet need is served. Consequently, if multislice CT is to continue to emerge, it will have to be investigated from an outcomes and technology perspective. In other words, did the use of multislice CT improve patient outcomes? Did it do so cost-effectively? The tools and techniques of outcomes and technology assessment should be followed in the design of prospective trials that aim to address the following hypothesis: Multislice CT cost-effectively improves net health outcomes (in appropriate disease settings). Only in this way, by constructing clinical trials with these ends in sight, can such a new innovation begin to gain wide acceptance and reimbursement.

The current health care marketplace is extremely competitive and eager to criticize innovation because of the perception that innovation translates into increased spending. As widely espoused by health care policymakers, the increase in health care spending in the past 3 decades has been disproportionately attributed to the introduction and utilization of medical technology. Consequently, proponents of a new innovation must address this fact and seek to corroborate the value of their technology by demonstrating its cost-effective clinical utility in emerging disease management paradigms. By following such conventions and addressing such concerns, proponents of an innovation are much more likely to witness the adoption and diffusion of their technology on a broad basis. By ignoring such a perspective and payor requirements for establishing coverage and reimbursement guidelines, it is more likely that an innovation will face scrutiny that requires a high level of justification. Early in the life of an innovation, then, key stakeholders must determine whether their product is intended for wide or limited adoption. In doing so, they will answer their own concerns regarding the future of their technology.


Frank J. Papatheofanis, MD, PhD, is assistant professor, Department of Radiology, and The Advanced Medical Technology Assessment and Policy Program, University of California, San Diego.