CCTA will play an essential role in the cath labs of the future

Collet said the field is evolving toward performing a coronary CTA before catheterization to extract both anatomic and physiologic data, creating a personalized treatment strategy that eliminates guesswork. CCTA offers much more information about the disease than any previous noninvasive techniques, acting as a gatekeeper for the cath lab.

"There has been an evolution in the CT software driven by AI and an evolution in the hardware component, which have made the pictures clearer. The conjunction of these things have led to a more accurate assessment of both the plaque analysis and the physiological aspect. So there is now this possibility of using AI to understand not only if there is any stenosis, but also to understand what is behind the stenosis, if there is a lipid-core plaque, if there is calcium, how long the plaque is, what the relevant information is in terms of the length of the stent and the diameter of the stent needed," Collet said

He added that FFR-CT can show which stenosis in the coronary tree is flow-limiting, which is the appropriateness criteria for an intervention in the United States. This can save both time and costs in the cath lab. The FFR-CT can show how the flow pressure is lost along the vessel to determine what is best to treat the patient. If the pattern shows a very focal segment of the vessel, that is ideal for PCI. But when the pressure losses are diffused, PCI outcomes are worse and the procedure may not lead to the needed improvements.

CCTA can offer more information information than nuclear imaging

Traditionally, nuclear stress testing served as a gatekeeper for invasive angiography for decades based on its functional information. But Collet said CCTA now offers both functional and anatomic data—plus the ability to stratify risk based on plaque composition.

“Lipid-rich plaques have about five times higher risk of events than non-lipid plaques,” he said. “So you can risk stratify the patient better based on the plaque composition,"

CCTA offers noninvasive disease monitoring

Beyond acute cases, Collet sees CCTA as the foundation for a paradigm shift in longitudinal management of coronary artery disease. Physicians can monitor plaque regression or progression over time, assessing whether medical therapy is truly effective at reducing atheroma volume and not just lowering blood lipids.

"I see CCTA evolving and becoming the cornerstone of the management of patients with coronary artery disease. And the reason is, you can start medication for treating atherosclerosis and you can repeat the scan to understand whether the medication was effective. Then you can really make a surveillance of the disease in a way that was not possible before. Then with AI, you have then an objective parameter to understand what the changes are in plaque volume and composition from the medication. So I think it is really personalizing care," Collet explained. "I personally seen spectacular cases of plaque regression."

CT-guided calcium characterization is the next frontier

Collet, an interventional cardiologist himself, emphasized that CCTA will also play a growing role inside the cath lab to help better manage heavily calcified lesions that require vessel preparation prior to PCI. Detailed calcium mapping can now be performed noninvasively, guiding lesion preparation and device selection.

“With CT, we can look at calcium morphology—arc, thickness, and now even density,” he said. “Density tells us about the rigidity of the calcification, which helps determine whether to use techniques like intravascular lithotripsy (IVL) or cutting balloons for optimal stent expansion.”

Also, CCTA is able to show the Hounsfield units of the materials, which correlates to how hard it is. Collet believes that in the future, CT will also be used in PCI pre-planning to choose devices best suited for the lesion. While IVL is seen as a breakthrough in breaking up calcium without vessel trauma, it is also more expensive than using traditional balloon angioplasty or cutting balloons. He said CT might be able to determine which devices can be used and which will be ineffective to reduce procedure time and the devices used to cut costs.

For now, he said this area of calcium classification is a new frontier of research using CCTA, so larger trials are needed to show how effective it is.