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GE's HeartFusion debuts at ACC meeting Oncology is the runaway leader in PET/CT applications, accounting for 90% or more of the studies performed with this hybrid technology. Vendors would like to expand its scope as a way to
GE's HeartFusion debuts at ACC meeting
Oncology is the runaway leader in PET/CT applications, accounting for 90% or more of the studies performed with this hybrid technology. Vendors would like to expand its scope as a way to increase product sales.
At the annual meeting of the American College of Cardiology March 7 to 10 in New Orleans, GE Healthcare formally recognized cardiology as one such opportunity, unveiling a PET/CT software tool called HeartFusion. HeartFusion aligns the coronary tree created using CT angiography with PET perfusion data, providing the means to quantify and analyze the impact of atherosclerotic lesions on the heart.
"Although the lesion may be diffuse, you want to understand which is the most significant lesion in the coronary artery tree," said Dr. Karim Benali, global manager for cardiology PET/CT and nuclear medicine at GE Healthcare.
GE and Emory University collaborated on the development of HeartFusion, which works with tools available as part of the Emory Cardiac (EC) Toolbox. The new product is available only from GE under an exclusive license with Syntermed, which makes EC Toolbox available under less restrictive agreements with GE and other OEMs.
HeartFusion requires GE CardIQ Analysis software, which post-processes data to display, reformat, and analyze 2D and 3D cardiac CT images. CardIQ allows qualitative and quantitative assessment of heart and coronary artery anatomy. HeartFusion and CardIQ together allow interactive display matches of anatomical lesions and functional defects. They allow the processing of perfusion and viability studies, rendering match/mismatch analyses that allow the comparison of perfusion to viability as a means to enhance treatment planning.
"We think PET/CT will play a role in reducing unnecessary invasive procedures and will also help provide a more comprehensive approach to coronary artery disease, a better tailoring of the treatment and monitoring of the vascular response," Benali said.
Competing PET/CT vendors are working on many of the same capabilities. Philips Medical Systems is working with Syntermed and Emory University on a software package with tools that address wall motion, perfusion, and viability, as well as radiotracer protocols and reference databases. In development is an algorithm that superimposes the CT-derived coronary tree on a PET perfusion scan. A commercial version of the software is expected later this year.
"We have shipped already one version of that software to one of our luminary sites and we expect in the near future to further develop the software and better integrate it with our portfolio," said Deepak Malhotra, Philips' director of PET marketing.
Siemens Medical Solutions and CPS Innovations, a joint venture between Siemens and CTI Molecular Imaging, has similarly adapted the EC Toolbox and software from the University of Michigan to fuse PET images and CT coronary angiograms. These technologies have been built into Siemens' PET/CTs, which include CPS's PET scanners, and into CTI's hybrids, which include CTs from Siemens. Executives from the two companies claim the high ground of cardiac PET/CT by virtue of the detector crystal built into their products. LSO (lutetium oxyorthosilicate) is faster than any other such crystal on the market, they said, providing the fast response needed to take advantage of the cardiac radiotracer rubidium, which has a half-life of just 76 seconds.
Jonathan Frey, Siemens director of PET marketing, characterizes rubidium as one of the biggest barriers to the widespread adoption of cardiac PET/CT. The radiotracer requires high-efficiency tomographs to obtain enough counts to produce adequate images but is very expensive because it is produced in a column generator and not a cyclotron. A replacement is not yet in sight, but one long-term possibility is a fluorinated radiotracer that would take advantage of the same distribution channels used for FDG, which is commonly used in oncological applications.
GE, Siemens, CPS, and Philips each are encouraging research into cardiac PET/CT applications at luminary sites. Yet none claims more than a handful of such sites dedicated to cardiac studies. They insist, however, that the capability to do cardiac PET/CT is widespread, as most PET/CTs are sold with the software necessary for cardiac imaging.
"Given the price of a PET/CT, the options that go with it are relatively cheap," Frey said. "So when hospitals budget for PET/CT, they tend to budget high and get as much as they can."
Holding back the use of these systems in cardiology is lack of reimbursement. Despite decades of availability, PET is reimbursed for only a few very select cardiac applications, as the far more cost-efficient SPECT handles the bulk of functional cardiac assessment. The adoption of coronary CT angiography could change this, according to Brad Herrington, CPS vice president of marketing.
"Cardiac CT is raising the question of how different technologies might be applied," he said. "Cardiologists will want PET/CT if their combination provides more information than either alone."
Optimized hybrid cardiology systems might provide a better understanding of vulnerable plaques, which are prone to rupture and can form blood clots that clog a vessel. The future development of targeted radiotracers could allow the detection of these plaques and CT, as it has done in oncology, could provide the anatomical context.