Where is PET today?
• Higher Diagnostic Accuracy
• Improved Efficiencies
• Lower Radiation Exposure
• Fewer Attenuation Artifacts
The diagnostic accuracy for Cardiac PET MPI has been established from multiple studies and shown to be superior to conventional SPECT MPI with regards to both sensitivity and specificity. This, combined with a documented higher image quality provides compelling reasons to move to Cardiac PET. Additional factors favoring PET MPI to SPECT MPI include minimized radiation exposure to both patients and staff preforming procedures. The average radiation exposure for a rest/stress Cardiac PET using 40mCi of Rubidium-82 is 3-4mSv when compared to 10-15 mSv for single Isotope and 20-25 mSv for dual isotope SPECT.
In addition using 3D imaging techniques can lead to ever further reduction radiation exposure. Cardiac PET offers additional information to improve diagnostic accuracy such as reversible wall motion abnormalities and myocardial blood flow is now commonly implemented in many PET laboratories. Laboratory efficiency is also a major factor for considering PET. Although it is commonly assumed that PET instrumentation is exponentially more expensive than SPECT, for those considering PET, it is important to recognize the breadth of available equipment. Dedicated line-source PET as well as 8-16 slice PET/CT cameras are in fact competitive in cost with new high-end SPECT cameras. As the field of imaging moves from “volume to value” in which downstream testing is targeted towards those needing intervention, Cardiac PET is an excellent option. Finally, as the depth of other cardiovascular imaging procedures used to diagnose myocardial viability, cardiac sarcoid evaluation, inflammation/infection imaging take on more relevance, Cardiac PET is becoming a vital diagnostic tool in cardiovascular practice.
Where are we going?
Cardiac PET in the future is also compelling. From an overall perspective, those procedures that offer the most benefit to society will gain use and acceptance. The higher accuracy and image quality of Cardiac PET imaging will continue to demonstrate value in reserving down-stream evaluation for those patients needing procedures, not diagnosis. Current multi-center research trials being performed now will yield result in data that supports the growing value of PET. Of great interest and excitement is the breadth of the development of new Cardiac PET tracers to grow and expand the indications to preform Cardiac PET. There are two new F-18 perfusion tracers in FDA development now that will provide better image quality and the ability to perform exercise stress with Cardiac PET MPI procedures, a limitation in the current scheme. The longer half-life (2 hours) will also mean that laboratories will be able to purchase the tracer on a patient-by-patient basis. An ischemic memory tracer in development offers some unique features to identifying CAD, perhaps without stress testing. A neuronal imaging agent analogous to mIBG but with much higher imaging quality may open this area for further research and indications. Further, F-18 FDG imaging for cardiac indications continues to grow in value and use in the clinical setting. Finally, as the Cardiac PET volume grows, manufacturers are looking towards development of new, lower cost, and targeted PET/CT cameras for the cardiac market.