Nuclear cardiology expands beyond perfusion imaging as it enters a new era
Nuclear cardiology is entering a new era—one that goes well beyond the traditional focus on myocardial perfusion imaging. According to Marcelo Di Carli, MD, chief of the division of nuclear medicine and molecular imaging and executive director of cardiovascular imaging at Brigham and Women’s Hospital, the field is rapidly expanding into diagnosing and monitoring complex cardiac diseases such as amyloidosis, sarcoidosis, myocarditis and even cardiovascular infections.
"It's a very exciting that nuclear cardiology is not just perfusion imaging, there are other areas where nuclear cardiology is fairly unique in its role," Di Carli, editor-in-chief of the Journal of Nuclear Cardiology, told Cardiovascular Business.
Amyloidosis imaging becomes routine
Perhaps the most transformative development, Di Carli said, has been the adoption of nuclear imaging as the primary non-biopsy method for diagnosing cardiac amyloidosis. Using bone-avid radiotracers such as pyrophosphate scans, clinicians can now make a definitive diagnosis without the need for invasive tissue biopsy.
“We have one of the most available, least expensive and powerful tools to make a non-biopsy diagnosis of cardiac amyloidosis,” he explained. “I would say 80-90% of patients now being diagnosed are using this pathway.”
This approach, combining bone-avid tracer imaging with laboratory testing to rule out other amyloid types, is now endorsed in clinical guidelines and recognized by the FDA. It is also serving as a diagnostic gateway for enrollment in large clinical trials evaluating new therapeutics for cardiac amyloidosis.
New amyloid-targeted tracers for PET and SPECT imaging are also emerging. This is enabling the assessment of treatment response.
"These new amyloid-targeted and specific radiotracers for both PET and SPECT that are going to change not only in how we make the diagnosis, but importantly how we track response to therapy," Di Carli said. "These treatments are very expensive and we need to be able to really identify non-responders rather quickly so that we give the patient a chance to improve outcomes."
Di Carli said recent studies using Medicare data will be published within the next couple months will show a clear upward trend in amyloidosis imaging.
“We’re seeing a lot of referrals for amyloid imaging, particularly at centers that also have treatment programs,” he said. “And now that awareness is growing, more clinicians are recognizing that if you don’t suspect the disease, you won’t diagnose it.”
Imaging cardiac inflammation and infection
Beyond amyloidosis, nuclear cardiology is increasingly used to image inflammation and infection in the myocardium, especially in diseases such as cardiac sarcoidosis and myocarditis.
With the rapid growth of patients getting cardiovascular implants like valves, pacemakers and defibrillators, there has been a rise in cardiovascular infections. Fluorodeoxyglucose (FDG) PET imaging is now recommended by both European and U.S. guidelines to detect prosthetic valve endocarditis.
"If you have a prosthetic valve and there is a suspicion of valvular endocarditis, PET has a unique role in making a diagnosis because other techniques are more limited. It is also guiding therapy, selecting who needs to go to surgery and who can be treated with antibiotics and tracking the response," Di Carli said.
This has created a lot of excitement over the last five years, with a lot of young imagers coming to the American Society of Nuclear Cardiology meetings. "They want to learn about these new techniques because they recognize that this is going to be part of the future practice," he 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: [email protected]