Key trends and takeaways in cardiac CT at SCCT 2023

AI dominated new technology discussions 

"We have a big focus on the rise of artificial intelligence (AI) and machine learning, and I think that has been a core part of this year's meeting," Nicol told Cardiovascular Business. "I think it is becoming more real for people because we are not just hearing about it more and more, but more people actually have their hands on it. But I think we still have an educational gap where we are in the low lands of trying to understand this technology, which is not going away and I think this will define what we do for many years to come."

He noted there was a lot of interest in the day-long, pre-program seminar on AI algorithms developed for CT angiography (CTA). It covered how AI is developed and moves through the U.S. Food and Drug Administration (FDA) review process, and how it is being implemented now in practice. 

AI was mentioned in nearly all the sessions Cardiovascular Business attended, and there were several sessions focused on AI applications. Nicol said several AI sessions he attended were standing room only because of the high level of interest. AI in CTA also now has large datasets showing its performance in real-world practice. One presentation at SCCT included more than 2 million patient cases that were reviewed by one AI algorithm and showed the use of CT coronary angiography (CCTA) directly correlated with a reduction in cardiovascular death. Nicol noted it is not the scan but the information CT provides that led to actions taken for therapy changes that led to better patient outcomes. 

At least 13 vendors on the SCCT expo show floor had FDA-cleared or -pending AI products. The biggest of these was HeartFlow, which developed the first AI-based virtual fractional flow reserve technology using CT scans (FFR-CT), which became the first AI algorithm included in U.S. cardiology guidelines. The company presented three new positive studies on its new-generation AI products at the meeting. Results showed its AI soft plaque analysis and AI for first-pass reads of coronaries to highlight areas of interest for radiologists. The studies showed the AI could improve therapy decisions, better risk stratify patients and speed reading times. 

Reimbursements and running the business end of CTA

SCCT recognized that, as more centers create cardiac CT programs, there is a need to address the business side of healthcare. While physicians were trained to diagnose and care for patients, they were not trained in the accounting and business side of the clinical operations. SCCT held an afternoon-long session on the business side of cardiac CT the first day of the conference to address this need.

Since its creation in 2005, SCCT has focused largely on developing the clinical evidence in studies necessary to show CTA's clinical value. This has led to CTA's inclusion in the 2021 chest pain guidelines and to growing acceptance of its use, sometimes over other traditional imaging modalities. The society is now changing its focus of evidence collection toward advocacy for reimbursement. SCCT recently hired lobbyists in Washington and is becoming more active in discussions with legislators, payers and Medicare.

"There is concern in the field that reimbursement for CT has gone down despite all the evidence, and that remains an ongoing challenge on the business side of CT. Anyone who works in the U.S. healthcare system knows this is not easy," Nicol said. 

In the past year, SCCT also created the SCCT Starter Kit program to help providers create cardiac CT programs. This includes technical information on what centers need for a program in terms of hardware, software, IT support, physical space, staffing, training, building referrals and billing. 

Cultural shift in cardiac imaging trends is slow

Nicol said that, while there is now a large number of clinical trials showing the value of cardiac CT, which led to it being added to the guidelines, it takes time for medical culture to catch up and new approaches to take hold. He said it is difficult to ask people to change the way they have been practicing medicine for years. He said these things take time because of the need for educating clinicians and the workforce to develop to support growing CT programs. And it is not just referring physicians. Not all radiologists or cardiac imagers or technologists have a deep understanding of CT, so it takes time for them to get up to speed before they can create or expand cardiac CT programs. 

Like the U.K. AI study Nicol mentioned above, it may take that type of real-world, drastic change in outcomes before people begin to start using the technology.

There has been a lot of debate over the past few years about which test is right for a patient at which time and circumstance. This has been spurred partly by the growth of CTA, making other modalities such as echo, MRI and especially cardiac nuclear imaging fearful CT may draw away more patient volume. The growth of multimodality imaging experts has produced calls for developing evidence-based guidelines for picking the best test for a specific patient. The old-school mentality where imagers spent their careers using a single modality has changed significantly in the past decade or so. It is now all about picking the right test based on the clinical questions being asked.

Nicol said no one modality is a one-stop shop to get all the answers, and no one is suggesting that some modalities may be obsolete. But as technology changes, he said, some modalities may be used differently than in the past. With a major focus now on ways to lower healthcare costs and movement away from fee-for-service to value-based payment models, cost comparisons between modalities may become a bigger part of testing decisions.

Limitations of CT are being solved by new technology advances

Cardiac CT has faced several technical challenges in the past, including high doses of radiation, slow temporal resolution to acquire images and the time required to post-process the data sets. However, Nicol said the technology is always changing, and these three areas have all been overcome in the past several years with the advent of automation, artificial intelligence, better detectors and new iterative reconstruction technologies. One limitation that continues to come up is the inability of CT to image hearts with heavy calcium or metal implants like stents, valves and left ventricular assist devices (LVADs). Even these challenges are being overcome now with the introduction of metal artifact reduction software, spectral CT and photon counting CT. Metal artifact reduction algorithms can greatly reduce or eliminate streaking and metal blooming artifacts. Nicol said spectral CT, or photo counting CT with its inherent spectral imaging built into all images, can dial down calcium, metals or other elements in images to make them readable. Or it can allow the dialing up of elements like iodine in images so less contrast is needed. 

Images shown during SCCT sessions from cardiac photon counting CT scans clearly showed soft plaques within heavily calcified vessels and within stents, which would have been very difficult in years past using standard CT technology. 

Record SCCT attendance shows growing interest in cardiac CT

Pre-COVID, SCCT averaged around 750 attendees at its meetings over the past decade. However, post-COVID and with the addition of CTA with a Class 1A recommendation in the 2021 Chest Pain Guidelines, the society hit a record number in 2022 and had its biggest attendance yet with about 1,000 attendees in 2023. Nicol said this points to the rapid rise in interest in CTA the past couple years. 

"We are 30% larger this year than in any previous meeting," Nicol said. 

An early indicator at the meeting that there were more attendees than usual was at the Women in CT reception, which expected about 30 people and ended up with closer to 100.  

Structural heart disease training sessions sold-out

Another hot topic was the use of imaging in structural heart disease. He said this has now evolved beyond transcatheter aortic valve replacement (TAVR) and left atrial appendage occlusion (LAAO) planning to now include growing numbers of tricuspid, mitral and pulmonary valve interventions. There was a pre-program all-day session on structural heart imaging and post-processing workups that Nicol said sold out very quickly, showing the high level of interest in this area.