Imaging economics may ultimately drive U.S. CCTA policy

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PHOENIX–Although recent technological advances in multi-detector CT have refined the capabilities of the modality to perform cardiac CT angiography (CCTA), larger economic issues surrounding the utilization of diagnostic imaging may yet impact reimbursement approval for the exam, according to a presentation this weekend at the 2008 North American Society for Cardiovascular Imaging (NASCI) annual meeting.

“When we think about the future of coronary CTA, are we talking technological advancements; or are we talking about the economic environment and our ability to move forward?” said Pamela K. Woodard, MD, from the Mallinckrodt Institute of Radiology at Washington University School of Medicine in St. Louis, who discussed the future of CCTA.

Woodard, who is also the 2008 president of NASCI, noted that this is a very difficult time for CCTA procedures.

“At the same time that we’re making technological advances in CCTA, we’re having the reins pulled on us because of the impact, in the long run, that some of the advances may lead to higher costs, and thus, won’t be reimbursed by private insurance companies, Medicaid or Medicare,” she said.

Developments on the technology front in recent years have markedly advanced the capabilities for CCTA, Woodward noted.

The introduction of dual-source, dual-energy CT has enabled heart-rate independent exams with a resolution of 83 milliseconds, she said. In addition, further evolution in detectors, from 64-slice to 128-slice and higher, have also improved the temporal resolution capabilities of CCTA.

Software developments have also played an important role in furthering the capabilities of CCTA. Weighted, filtered back projection algorithms with volume projection reconstruction have eliminated many artifacts that hindered early efforts at CCTA.

Woodard pointed to wider detector arrays, cone-beam reconstruction and scatter correction, the use of next-generation scatter grids and new materials in detector composition as a few of the recent technology enhancements providing increased clinical capabilities.

Garnet detectors, Woodward said, hold great promise in improving spatial resolution by leveraging light-handling properties as well as aiding in noise reduction. The material may also allow for faster speed and a decrease in radiation dose.

Despite these advances in technology, the path ahead for CCTA is not altogether clear. Woodard noted that cardiovascular imaging has been described as the largest percentage of the Centers for Medicare & Medicaid Services (CMS) imaging budget. Of particular concern is a report this past June from the Government Accounting Office (GAO) on the rapid spending growth and shift to physician offices of Medicare Part B imaging services reimbursement. The GAO stated that this indicates a need for CMS to consider additional management practices.

“Advanced imaging services—CT, MRI, and nuclear medicine—saw the highest growth rates,” Woodard said, citing the report. “Spending on these advanced imaging modalities increased almost twice as fast, at an average annual rate of 17 percent, as spending on services in the three other imaging modalities—ultrasound, standard imaging (mostly x-rays) and procedures that use imaging.”

High-tech imaging modalities will probably take the greatest hit in efforts to rein in imaging costs, noted Woodard. For example, earlier this year, CMS only eased a decision to not provide a National Coverage Determination (NCD) for CCTA through the combined efforts of many professional societies.

Woodard and other professional colleagues discussed the issue with CMS and found its objections to a CCTA NCD hinged on five questions:

1. What are the outcomes after a negative CCTA?
2. Is any further imaging for coronary artery disease necessary after CCTA?
3. What (how long) is the window of warranty for a patient’s CCTA results?
4. Can it be proved that CCTA won’t be additive?
5. What guidance is available to providers at a local level?

According to Woodard, these issues have not been conclusively laid to rest, and thus the CMS proposal to rescind a CCTA NCD could resurface at a future date.

Clinicians desiring to continue the use of reimbursed CCTA in their practice need to be aware of four key influencers that may determine the future of the procedure.

“Are we being fiscally responsible?” Woodard asked. “Are appropriateness guidelines in place and are they being followed for a given imaging technique? Are we being safe (i.e., radiation dose)?