Coronary CTA establishes new markets, standards

March 1, 2006

The adoption of new imaging technologies presents multiple challenges to hospitals, radiologists, cardiologists, payers, and vendors. Sixty-four-slice CT, which has enabled the clinical evolution and market adoption of coronary CT angiography, is not a disruptive technology. But CCTA is, as evidenced by questions raised about its clinical impact and the push for new credentialing standards by organizations.

The adoption of new imaging technologies presents multiple challenges to hospitals, radiologists, cardiologists, payers, and vendors. Sixty-four-slice CT, which has enabled the clinical evolution and market adoption of coronary CT angiography, is not a disruptive technology. But CCTA is, as evidenced by questions raised about its clinical impact and the push for new credentialing standards by organizations.

CCTA is not just a CT application. It is a coronary artery disease management tool, and its adoption will be influenced by its effectiveness on that basis.

The challenge of CCTA demonstrates the need for a robust technology adoption process within a hospital or physician practice. The issue is a lightning rod at a time when diagnostic imaging faces numerous challenges, ranging from increased utilization to declining reimbursement and the growth of imaging by nonradiologists. Moreover, cardiology interest in the diagnosis and treatment of vulnerable plaque is expanding across the entire peripheral vascular system.

Clayton Christiansen, a professor of business administration at Harvard Business School and a thought leader on the impact of disruptive technologies, has described two types of technologies that enter the marketplace (The Innovator's Dilemma. Harvard Business School Press, 1997). Sustaining technologies maintain a consistent rate of improvement. Disruptive technologies introduce very different features from those historically valued by mainstream customers. In their early stages, disruptive technologies often perform far worse along one or two dimensions that are particularly important to those customers. Eventually, they create new markets and standards and significantly change behavior.

The concept of technology evolution as outlined by Christiansen is demonstrated in Figure 1. The upper and lower performance levels for a given technology are represented by A and B, respectively. The technology, represented by C, will evolve over time from a lower to a higher level of performance. The relatively linear path shown is characteristic of a sustaining technology, evolving toward market expectations and promoted by market leaders, luminaries, and established vendors. Innovations enable development of a new disruptive technology (D). The initial performance is typically below market standards.

Cellular phones and digital cameras serve as examples of the disruptive technology model. Over time, initial performance improves, ultimately surpassing that of the previous market leading technology (C). By their very nature, disruptive technologies such as portable computer hard drives, coronary stents, CT scanners, and polio vaccines have changed the market value of earlier technologies and created new standards and behaviors.

The Sg2 version of this model, applied to cardiac catheterization lab and CCTA technologies, is demonstrated in Figure 2. Upper and lower market performance expectations are indicated by A and B, respectively. Premium diagnostic catheterization lab technology performance is indicated as C. The advances that have contributed to that performance include improved image intensifiers, flat-panel detectors, and improved stands. The introduction of noninvasive CT angiography of the coronaries led to a new disruptive technology, early CCTA technology (D).

Initial performance of CCTA was intriguing but below market expectations. Sixteen-slice CT prepared the way for 64-slice CCTA, successfully attracting the attention of both cardiology and radiology markets by the fourth quarter of 2004. CCTA is still early in its evolution and clinical validation, although many clinicians contend that it is ready for widespread market adoption (Figure 3).

It is possible that CCTA technology will eventually surpass the diagnostic clinical performance of diagnostic catheterization labs. Conversely, emerging 3D interventional x-ray systems that simulate CT soft-tissue imaging may evolve to offer true volumetric cath lab imaging and interventions. The challenge lies in differentiating between poorly performing new technologies and early disruptive technologies, a process that requires extraordinary analytical resources.


We have invested considerable time and resources working with hospitals and physicians to develop strategies for adopting new clinical and operational technologies, particularly disruptive technologies such as computerized physician order entry, e-ICU, surgical guidance systems, robotics, endovascular applications, new implants, and molecular diagnostics.

We have confirmed a consistent pattern of new technology adoption by the healthcare market over the past five years. As new technologies evolve, they are sequentially adopted by different market segments based on clinical validation, market penetration, risk, and economics. Each segment is characterized by different values and strategies.

- Innovators. Market innovators are typically academic sites, savvy technocrats, or entrepreneurs working with vendors to establish the basic clinical performance and configurations of new technologies. They publish and create market awareness of the new technology.

- Early adopters. Early adopters are typically a mix of physician practices, academic medical centers, and community hospitals. They establish market standards and protocols for clinical performance.

Innovators and early adopters share several important characteristics. Both are attempting to establish the value of new technologies and services, albeit for different motivations. They both use new technologies without the benefit of clinical trials. They are visionary and technology driven.

- Consensus adopters. These practical adopters seek to add a new service and make adoption decisions based on availability of clinical evidence, standardized protocols, target patient populations, and routine reimbursement.

- Cautious adopters. Risk-averse cautious adopters typically wait for clinical evidence that establishes the value of the new technology in managing specific populations that exist in their market. Cautious and consensus adopters combined represent 60% to 80% of the market, depending on the technology.

- Late adopters. These adopters are driven by economics rather than clinical evidence. They adopt technologies when competitively required to do so in order to match local standards of care.

This adoption model offers practical insights into market dynamics. Adoption strategy and execution will have a greater impact on practice success than timing. For example, if radiology practices deliver technically strong, but clinically weak CCTA reports, the impact will be to encourage competitors to usurp that business.

The model also validates various group dynamics and strategies. For example, cardiologists tend to be among the strongest evidence-based practitioners. When trials data are published, cardiologists move rapidly to adopt new technologies that improve patient management and outcomes.

Cardiology practices are currently purchasing limited numbers of 64-slice scanners for CCTA and are lobbying hospitals for CCTA reading privileges, but this represents a relatively small profile of the total cardiology market in 2006. Most radiology practices probably have less than two years to determine their vision for CCTA service before cardiologists adopt more aggressive purchasing.


Key clinical drivers for CT are cardiac applications and tissue characterization. But workflow and radiation dose efficiency need to be addressed to enable the growth of all CT procedures.

Improved temporal resolution is the single most challenging issue for refining CCTA performance as a routine clinical tool. Siemens is already tackling this issue with the introduction of a dual-tube scanner with faster temporal resolution. It is expected to be commercially available by year's end. The market will likely see much faster temporal resolution scanners that employ a mix of different technologies from GE, Siemens, and Philips within the next two years.

New dual-energy detector technologies hold promise for reducing coronary calcium blooming artifacts and improving tissue characterization within the myocardium. But new detector arrays that increase the number of slices will add little to validating more precise, reliable, and clinically relevant coronary artery imaging. These new detector arrays and, eventually, flat-panel detectors could enable imaging of an entire liver or heart in a single rotation. That capability could have a major impact on perfusion and angiogenesis imaging, but it is secondary to the need for faster temporal resolution by CCTA.

All of these applications, slices, and cardiac phase images will require improved workflow, data acquisition systems, and network infrastructures. Grid computing will eventually emerge as a necessary solution for real-time data processing, future applications, computer-aided diagnostics, and decision support tools.

CCTA performed with 64-slice CT may receive competition from another direction. The emergence of combined SPECT/64-slice CT systems from Siemens and Philips could affect adoption of CCTA. Since cardiac SPECT is well established in cardiology for evaluating myocardial perfusion, the combination of these two technologies could be viewed as an effective coronary perfusion assessment tool. Although 256-slice or flat- panel technology offers potential for whole heart perfusion with CT, the need for validation of that application is likely to slow adoption.

Although consensus adopters are beginning to step up acquisition of 64-slice CT scanners, CCTA will likely remain in the early adopter phase for one to two more years. As of January, fewer than 10 reports on 64-slice CCTA had been published. Each demonstrates its clinical integrity and high negative predictive value.

These first studies confirm the concept of CCTA and its role as a patient management tool. Subsequent studies will analyze advanced CCTA applications such as perfusion, dose reduction, scanning and clinical workflow, new analysis applications, patient protocols for distinct subpopulations, and comparisons with other diagnostic technologies.

Strong clinical validation will foster reimbursement decisions for CCTA, an essential benchmark if it is to be accepted by the broader consensus adopter market. Development of new CPT codes should enable clinical tracking and facilitate outcomes evaluations in the future.

CCTA for chest pain management in the emergency room is less advanced due to several factors:

- varying clinical performance across the 64-slice installed base;

- CT limitations in dealing with higher and variable heart rates;

- inability to administer beta blockers in many ER patients;

- left internal mammary artery bypass graft breath-hold limitations; and

- community hospital concerns for following new, nonvalidated ER chest pain protocols.

While as few as 5% of chest pain patients visiting the ER may present with acute coronary syndrome (Sg2 data), the role of CT in managing atypical chest pain is attractive due to its noninvasiveness and reported negative predictive value. The challenge for vendors is to provide consistent clinical performance and to facilitate trials establishing that performance in chest pain subpopulations.

We frequently speak with hospital administrators and physicians who have been given the impression that CCTA is a replacement for diagnostic catheterization procedures. CCTA is not presently such a replacement. It does, however, effectively displace diagnostic catheterization in some patients by noninvasively identifying significant coronary artery disease. For example, identification of a significant left anterior descending stenosis leads to a scheduled angioplasty procedure, effectively displacing the diagnostic catheterization step in management of a cardiac patient (Figure 4).

In the next five years, CCTA will likely drive growth of angioplasty volumes and significantly decrease the total number of expensive, higher risk diagnostic catheterization procedures. Nationally, CCTA will force a shift in scheduled diagnostic catheterization volumes, although this will vary greatly across markets. The negative predictive value of CCTA eliminates some diagnostic catheterizations, but a small yet significant percentage of patients will still undergo follow-up diagnostic catheterizations. It is expected that payers will develop reimbursement strategies that limit the impact of self-referral from SPECT to CCTA to diagnostic catheterization to angioplasty.

Full replacement of diagnostic catheterization procedures by CCTA will be accepted by cardiologists only if large-scale trials validate its equivalency across specific populations of patients. If that level of CCTA performance is reached, it will be with a more advanced platform than currently exists. Since diagnostic catheterizations represent 30% to 70% of total catheterization lab volumes, the impact of CCTA on shifting utilization could be significant through the next decade.


Successful execution of CCTA comes down to an effective technology adoption strategy. Early adopters need a process to adapt to the changes in protocols, technology, service, and market demands. Moreover, an effective CCTA service must meet or exceed the clinical and operational needs of its customers. The CCTA report must be timely and provide clinical value and actionable findings. Results must be viewed by the market as positively and consistently influencing management.

The long-term success of a CCTA service requires effective execution, strong physician relationships, and clinical impact. If this sounds like radiology or cardiology business management 101, it is. The bottom line is meeting or exceeding the needs of customers.

Cardiologists will need to develop strong clinical and technical CT skills. If they do not develop this expertise and help shape the growth of CT technology and practice, they will be viewed as self-referring opportunists by hospitals, their peers, payers, and healthcare policy makers.

Radiologists will need to develop a new ability to consistently provide clinically integrated and actionable reports for managing cardiovascular disease patients. CCTA is a wake-up call for radiology practices to evaluate their service delivery, including providing reports that add clinical value across all applications. In addition, CCTA presents radiology with an opportunity to establish its role in the introduction and development of new imaging technologies.

Disruptive technologies are engines of change. What credentialing structure can best facilitate long-term delivery of a CCTA service that supports innovative coronary artery disease management? Which operational structure will deliver safety, quality, and clinical effectiveness? Hospitals will select from the following:

- exclusive radiology interpretations;

- image interpretation divided among cardiologists (coronaries) and radiologists (chest/mediastinum);

- a joint cardiovascular CT service; or

- incorporation of CCTA into a broader cardiovascular center.

Based on the experiences of the business sector in developing disruptive technologies, the establishment of jointly staffed, independent CCTA services may be the most appropriate strategy for CCTA implementation.

The clinical impact of CCTA is in the innovation of cardiac care. The disruptive challenge is that CCTA requires a combination of strong technical knowledge and clinically integrated interpretation for innovative patient management. Dr. Daniel Federman, a distinguished professor of medicine at Harvard Medical School, summed up the reality of CCTA: "We in medicine all want progress, we just don't want change."

CCTA challenges cardiologists and radiologists with the basic economics and professional practice standards of both. The effective adoption of this technology will shape the evolution of both specialties and their respective service lines.

Mr. Silver and Mr. Farr are vice presidents at Sg2 in Skokie, IL. Mr. Sharma is a consultant at Sg2 in the imaging intelligence business. Sg2 provides consulting services to Philips, GE, Medtronics, and Siemens.