What is the ROI for upgrading nuclear cardiology labs?

"Our theme this year with ASNC is 'broaden your horizon,' but you cannot broaden your horizon unless you really modernize your lab and have updates in your technologies. To modernize a lab, it does not mean you have to buy completely new hardware. There are now some artificial intelligence (AI) tools you can buy that give you the same thing as buying a more expensive system," Al-Mallah explained. 

Change is happening, but it has been very slow. 

"It is not going to happen overnight, where one day we have ancient machines and the next we have all top-of-the-line [products], but I think administrators are aware that this trend cannot continue forever, and we need to adopt these newer technologies to best serve our patients," he added. "Otherwise you cannot compare images between a new 2023 model machine versus a 1990 or 2000 model machine. They just are not going to perform the same. The electronics are different and every tool is different."

Each lab needs to determine what makes the most sense for them, whether that is moving to a new PET system or software upgrades to their existing hardware.

"Optimization ends up being a multi-prong approach," Phillips said. "It is a not a one-size-fits-all for every nuclear lab in the country or around the world. There are technologic changes, there are software changes, there are protocol changes. What we want to do is make sure there is a big enough library of tools that everyone is looking at their image quality and ways to optimize it better. It is exciting that there are new ways to do attenuation, and there are ways to do atherosclerotic assessments on top of functional assessments."   

PET vs. SPECT, which is better?

PET is has a better imaging quality than SPECT with clearer images and very fast scans with rubidium-generator radiotracers that have a half-life of 75 seconds. This short-lived period of radiopharmaceutical radioactivity also decreases radiation exposure for the patient. 

However, PET requires the addition of a computed tomography (CT) scanner to help with attenuation correct on the images. These hybrid PET-CT systems are expensive and PET requires a different workflow in the lab. This has led to slow uptake of PET in the market, especially when many labs have been getting by with their older SPECT scanners. But PET-CT offers additional advantages over SPECT.

In addition to speed, the CT on PET systems enables the ability to perform coronary calcium scoring on every scan. Not only is this reimbursable, but it also adds additional value for the referring physicians with insights about the patient's 10-year risk of a heart attack and knowing the level of disease in their coronaries. CT attenuation also makes the imaging more accurate than stand-alone SPECT systems, which decreases the number of false-positives.

PET also allows the additional quantification of myocardial blood flow (MBF) in absolute terms in milliliter per minute, per gram of tissue. This offers a detailed assessment of a patient's ischemia to facilitate the diagnosis of multi-vessel CAD and offer the opportunity to monitor responses to lifestyle and risk factor modification, or the impact of therapeutic interventions.

"The PET scanners are the fastest, and adding flow does not add any time, it is just the way you acquire it and it is processed differently. So it is free data that does not require any additional radiation for the patient, no additional acquisition, no additional table time for the hospital, so the through-put is going to be the same," Al-Mallah explained. "Myocardial perfusion imaging (MPI) can be done in 30 minutes in a PET lab, and maybe with a table change, 45 minutes."

SPECT-CT hybrid imaging systems also have been introduced to the market in the past 20 years, with the CT designed to help with attenuation correction and offer anatomical imaging to overlay on the SPECT. But cost has been a barrier for some centers.

But even if a hospital does not want to pay for a hybrid imaging system to get the attenuation correction CT, Al-Mallah said they can still perform CT attenuation correction using a separate CT scanner in their department. Software packages now allow these separate CT images to be fused with the SPECT images in post-processing. He said the additional CT scan for attenuation takes 10 seconds to acquire. 

"There are also some centers that are using virtual attenuation correction, which is FDA approved from some vendors," Al-Mallah said. "It does take more processing power, so you need to make sure that the computers on the machine are capable of processing all this data and storage."

SPECT radiopharmaceuticals technetium-99m (99mTc)-sestamibi and thallium-201, may not be able to detect lesser degrees of ischemia as well as PET, but generally SPECT stress perfusion abnormalities can be identified with conventional SPECT in the majority cases.[1] 

Digital detectors were also introduced for PET and SPECT to replace the very bulky, older technology of photo-multiplier tubes. Direct digital detectors are not only smaller, but greatly improve image quality and the speed at which the detector can collect more photons, so images can be created much faster. 

Digital detector technology on SPECT systems also enables imaging times to be reduced, allowing half-time imaging. Or imaging times can be left at the standard duration and half the usual dose of radiotracer can be used. Digital detector technology has clear economic advantages by either reducing radiopharmaceutical supplies that are needed, or by enabling more patients to be scanned in a day. 

Newer nuclear imaging technologies improve image quality and reduce the number of tests

"The newer technologies are being adopted at different levels, based on different situations. But, it is definitely in the right direction because we are seeing more SPECT-CTs, more PET-CTs being installed, more digital PET and more AI solutions are being adopted in the labs," Al-Mallah said. "My arguments to administrators is to look at the return on investment from the improved imaging, because now we can avoid artifacts and have high-quality imaging. We also can avoid layered testing where we perform multiple tests to get to the final diagnosis, and that is all coming off the diagnosis-related group (DRG). But if you are doing one test and coming up with a diagnosis, that is saving money for the hospital. So the ROI for an administrator is going to be much higher than the cost of the test itself."

The DRG classification system was created to help lower healthcare costs and weight the complexity of a patient case. The Medicare Severity DRGs (MS-DRGs) for payment allows up to 25 procedures performed during the stay. 

Al-Mallah said it is important to outline the downstream savings of new technology beyond the test or diagnosis itself. For example, if there is a very obese patient and you can image them with one test and it answers the clinical questions, the hospital will save money. He said it is not just the cost of additional tests, but also extra costs due to potentially delayed treatment, longer length of stay, nursing costs and bed costs because the original scan was poor quality or inconclusive. 

"With our obese patients, they often have to come back for two days of imaging, and that is an inherent inefficiency in the process," Phillips said. "With the newer technologies, when you are able to image them more quickly and many times get a test done in one day, you are inherently improving your efficiency and improving your throughput."

He said this efficiency, freeing up the scanner for additional patients and cutting out the hassle to the patient for two days of testing to increase satisfaction scores are all good arguments to administrators for upgrading systems.

New, growing nuclear imaging applications require lab upgrades

Al-Mallah said there are several new technologies that are moving the subspecialty beyond the traditional role of perfusion imaging. He considers these key technologies for the future of cardiac nuclear imaging. 

Chief among the newer advancements in nuclear cardiology is the assessment of myocardial blood flow using PET. He said this quantification is now included in the guidelines and allows more accurate assessment of microvascular perfusion in the heart. He said this nuclear imaging technology is the best option for assessing patients with chest pain that do not have evidence of blocked coronary arteries. This includes patients with myocardial ischemia with no obstructive coronary arteries (INOCA) and myocardial infarction with non-obstructive coronary arteries (MINOCA).

"This is really going to be one of the niche applications of PET imaging that allows us to identify these patients and help guide them," Al-Mallah explained. 

Another technology area seeing rapid adoption is the use of cardiac amyloidosis SPECT imaging using technetium-99m pyrophosphate (PYP). The majority of patients with cardiac amyloidosis have myocardial amyloid deposits formed from misfolded light chain (AL) or transthyretin (TTR) proteins. Diagnosis of amyloidosis and differentiation between these types is important for prognosis, therapy and genetic counseling.[2] Use of PYP imaging also eliminates the need for biopsy in most patients, Al-Mallah explained. 

Find more cardiac amyloidosis news and video.

"Another application where we are seeing significant growth is inflammation imaging," he said. "While cardiac MRI and echo remain the first steps in the diagnosis of inflammation, the only modality we have right now to track the degree of inflammation and the response to therapy is cardiac PET with FDG."

This includes inflammation of the heart caused by sarcoidosis, lupus, rheumatoid arthritis or other causes.

Houston Methodist performed its first sarcoidosis scan of a patient just a few years ago, and now they perform four to six studies a day, Al-Mallah said. 

Infection imaging is another growth area, where nuclear imaging can show the location and extent of infections of cardiac pacing leads, cardiac implantable electrophysiology device (CIED) pockets, prosthetic valves, surgical clips and left ventricular assess devices (LVAD). He said it can be very challenging to determine the extent and severity of infections from echo of CT, but nuclear imaging can offer a much more accurate, pinpoint assessments.

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