Sources of Medical Technology Universities and Industry (1995) / Chapter Skim
Currently Skimming:
6 INNOVATION IN CARDIAC IMAGING
6 INNOVATION IN CARDIAC IMAGING
Pages 125-154
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 125... ...
This chapter presents some preliminary findings and hypotheses drawn from field interviews with key participants who are involved in the innovation process in two important and widely used technologies that provide diagnostic information about the heart: nuclear cardiology and echocardiography. These technologies pose some especially interesting problems for innovators since, in both instances, their development and eventual successful application required col 1Nathan Rosenberg, for example, has published a number of papers on this topic.
|
From page 126... ...
From this set of techniques we have selected two areas of technology that in recent decades have seen especially significant advances: nuclear cardiology and echocardiography.2 Nuclear medicine techniques are 20ther imaging technologies that have been used in this therapeutic area include X-ray imaging with contrast agents and magnetic resonance imaging (MRI)
|
From page 127... ...
We found the two streams of innovation to be largely nonoverlapping clinically, although this may change in the future as echocardiography evolves toward a more prominent place in the evaluation of coronary artery disease patients. Nuclear Cardiology Although radioisotope tracer techniques have been used sporadically in cardiology since the 1920s, their use for the evaluation of myocardial blood flow and pumping ability has become widespread only within the past 15 years.
|
From page 128... ...
Nuclear cardiology techniques have found other applications in the management of coronary artery disease. Measurements taken at rest or during stress have been shown to provide important information regarding a cardiac patient's long-term prognosis.
|
From page 129... ...
In the coming years we are likely to see continuing improvements in its accuracy, the breadth of clinical information it generates, and its ease of use. And, over the long term, echocardiography may pose a substantial competitive threat to diagnostic nuclear cardiology.
|
From page 130... ...
At least one clinician has predicted that intraluminal ultrasound imaging using these probes will eventually displace angiography as the "gold standard" for detecting and localizing coronary artery disease. A third effort is attempting to use subtle aspects of the ultrasound signal to characterize the tissues through which the signal has passed.
|
From page 131... ...
These changes represent incremental changes in the function and use of the innovation inspired by growing clinical and manufacturing experience. Examples from Echocardiography and Nuclear Cardiology Concept An innovation in imaging typically begins with an isolated investigator demonstrating the technological feasibility of a new technique.
|
From page 132... ...
FINKELSTEIN, KEVIN NEELS, AND GREGORY K BELL on computer-assisted image reconstruction of radioisotope scans before the wide dissemination of X-ray computed tomography.5 In the case of nuclear cardiology's SPECT camera, the demonstration took place at the University of Michigan, where John Keyes attached an early-generation planar gamma camera to a gantry and created the "Humongatron," the first SPECT camera.
|
From page 133... ...
There was only one major exception the development of the technetium-99 sestamibi radiopharmaceutical, which, because it did not involve development and/or operation of a complex, novel piece of equipment, could be developed by a collaborating pair of university-based research chemists at their own facilities.8 In contrast, the development of working prototypes of ultrasound systems capable of Color Doppler flow imaging or acoustic quantifi 7Ejection fraction is defined as the percent reduction in ventricular volume over the course of the beat cycle. A high ejection fraction (i.e., a large reduction in volume)
|
From page 134... ...
. Such a system redesign would require enormous time and effort; yet Color Doppler was coming on the heels of a longoverdue Pulse Doppler product and there were concerns about how long a complete redesign would take.
|
From page 135... ...
When the system was finally introduced, several engineers and clinicians agreed that the image quality the new units yielded was no better than the 64-channel units being replaced. Another example of the difficulties of commercializing a new technology is the development, in the early 1980s, of the multi-headed SPECT camera, which proceeded from a University of Texas laboratory to the Technicare subsidiary of Johnson & Johnson, whose engineers created a working prototype.
|
From page 136... ...
As ultrasound developed for cardiac applications through the late 1970s into the 1980s, the number of expert clinical cardiologists from major academic medical centers who served as consultants to most manufacturers of the technology was relatively small. Some of those doctors provided input to manufacturers developing or offering competing products, although all the consultants insist that the confidentiality of the process was preserved.
|
From page 137... ...
In this field, however, image quality is a highly individualistic perception, and it proved difficult for clinicians to describe what was good or bad about an image in a way that an engineer seeking to refine the system would find meaningful. In contrast, in nuclear cardiology the shortcomings of thallium-201-based images were well understood and researchers were able to develop new imaging agents and better cameras with properties designed to overcome those shortcomings.
|
From page 138... ...
Even the gamma cameras used in nuclear cardiology were often constructed from commercially available computers, sensors, and other components. Thus, the nature of the technology itself often shapes the institutional environment within which innovation takes place.
|
From page 139... ...
Individuals with formal clinical training were rare.9 The clinicians, on the other hand, were generally practicing cardiologists; their knowledge of the technological possibilities of these imaging modalities was necessarily limited. Because of this disciplinary orientation, decisionmakers in the innovating firms often had only a limited appreciation of the clinical utility of the devices they were developing.
|
From page 140... ...
Pulse Doppler could convey information only on blood flow velocity; Color Flow Doppler was required to obtain information on direction and turbulence. Yet at the time HP decided to develop the product there was considerable skepticism within the medical community about its eventual clinical utility.
|
From page 141... ...
Efforts to contain health care costs could slow the diffusion of new techniques into clinical practice and thereby lengthen the cycle of refinement leading to breakthroughs. Here both industrial firms and innovative clinicians are in something of a Catch-22.
|
From page 142... ...
The one area in which the constraints on the innovation process can be eased is within industry itself. The challenge for an established firm like HewlettPackard, in echocardiography, or DuPont Merck, in nuclear cardiology, is to maintain an entrepreneurial environment in which individual visionaries have enough freedom and sufficient resources to demonstrate the value of their ideas.
|
From page 143... ...
Our fieldwork revealed instances where a visionary led an all-encompassing lab effort to introduce a breakthrough new product, only to have the product subsequently stumble, damaging the company's position of technological leadership.l° An alternative to leadership by a visionary is leadership by a harvester. A harvester should be an extremely accomplished technologist, but one perhaps more capable of assessing both the technical feasibility and the clinical utility of competing projects than of generating new ideas.
|
From page 144... ...
Furthermore, a long-term relationship allows the consultant to acquire a greater appreciation for the capabilities of the base technology and may help generate new concepts for internal development. In both the concept and prototype stages, these practitioners represent ideal sanity checks to determine if an innovation might become the leading edge in clinical practice or be relegated to the fanatical fringe.
|
From page 145... ...
1990. Exercise thallium-201 scintigraphy in the diagnosis and prognosis of coronary artery disease.
|
From page 146... ...
He described thallium as a potassium analogue and recognized the relationship between blood flow and thallium uptake by the myocardium that is the foundation of thallium's usefulness as a perfusion imaging agent. He also developed a procedure for postirradiation purification of the cyclotron-produced radioisotope that was suitable for use in commercial-scale production.
|
From page 147... ...
By the late 1970s, numerous papers had been published documenting the diagnostic properties of thallium-201 imaging. Its value was well established as a tool for detecting the presence of coronary artery disease (CAD)
|
From page 148... ...
However, despite these systematic efforts to identify the appropriate role for thallium testing, the choice of diagnostic tests continues to be strongly influenced by individual physician preferences. APPENDIX B Tc-99 Sestamibi Tracer Tc-99 sestamibi is a technetium-based synthetic radioisotope with certain properties that enable it to produce images of the heart allowing for an assessment of the "viability" of cardiac muscle and the identification of the possible presence of coronary artery disease.
|
From page 149... ...
The Tc-99 agent eventually introduced by Squibb for cardiac imaging has not been quite as successful. Its extremely rapid washout properties make perfusion imaging even more technically challenging than with thallium-201.
|
From page 150... ...
pursued led to image improvement. These involved improved image reconstruction algorithms, better imaging agents, and the camera itself.
|
From page 151... ...
Clinical users, including some who had been skeptical of any improvement in accuracy with single-headed SPECT, have been more impressed with the images that are produced by these multi-detector cameras. And new cardiac imaging agents such as Tc-99 sestamibi are said to produce further improvements in the quality of SPECT images over those generated with thallium.
|
From page 152... ...
At the time, HP was heavily involved in development of Color Flow Doppler imaging. As a result, there were few resources to spare to pursue the TEE opportunity.
|
From page 153... ...
Ideally, the clinician wanted to place a cursor on the screen and detect blood velocity at a certain point. Color flow was essentially two-dimensional Doppler allowing the clinician to measure blood flow velocity, volume, and direction.
|
From page 154... ...
FINKELSTEIN, KEVIN NEELS, AND GREGORY K BELL Color Flow Doppler required engineering advances in signal processing.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.