SPECT still has an important role to play in nuclear cardiology
In cardiac nuclear imaging, there has been a push for labs to upgrade aging equipment that can sometimes be 15-20 years old with new technology that can offer more diagnostic information and clearer images. A big focus has been on positron emission tomography (PET) because of its increased capabilities over the traditional workhorse technology of single photon emission computed tomography (SPECT). However, most nuclear imaging experts say SPECT can still provide value.
Cardiovascular Business spoke with Timothy Bateman, MD, co-director of the cardiovascular radiologic imaging program at Saint Luke's Mid America Heart Institute and a professor of medicine at the University of Missouri-Kansas City School of Medicine, who shared his views on SPECT advances and its longevity in the coming years.
"I think that SPECT is going to endure and will have its place. Looking forward, I don't really see that people are going to have the luxury of making a decision that I'm going to be a SPECT-only lab or a PET-only lab. You really have to have both. That's just the reality. We're looking after a disease process that's endemic and we need tools. So I see at least for the next decade, this being a SPECT and PET world, not one or the other," Bateman, an American Society of Nuclear Cardiology (ASNC) past-president, explained.
He explained that SPECT image quality can be greatly improved with newer cameras that use cadmium zinc telluride (CZT), which allows for imaging in half the time or half the radiotracer dose. A second technology that he said is helping improve the accuracy of older SPECT systems is the use of artificial intelligence (AI) virtual attenuation correction software.
"The big advancement in SPECT over the last 10 years is CZT. It has the capability of attenuation correction with either CT or with one of these newer machine based models that are becoming more accepted. The image quality can be very good With CZT," Bateman said.
However, PET does deliver better overall image quality and offers the ability to quantify myocardial flow reserve (MFR), which offers much more information about microvascular flow in the myocardium that SPECT cannot provide. This can be helpful in diagnosing myocardial ischemia with no obstructive coronary arteries (INOCA) or to better quantify the overall impact of the patient's coronary disease.
"SPECT does not really have much in terms of flow quantification. One of the major advantages of PET is the opportunity to quantify myocardial blood flow, not just in a relative sense, but also be able to derive quantitative flows in milliliters per minute per gram of tissue, both at rest and at the peak of stress," Batman said.
PET also offers advantages in terms of shorter scan times and new tracers that can help image cardiac inflammation, infection and cardiac amyloidosis and sarcoidosis.
Despite these advantages, the cost of replacing all SPECT systems with PET would be very high and may not be needed. He said a lot of patients may not necessarily need MFR and just require a basic assessment.
"We do see an awful lot of patients who need to have a less sophisticated assessment," Bateman explained.
Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: dfornell@innovatehealthcare.com