How early can atherosclerosis be detected by coronary CT angiography? Insights from quantitative CT analysis of serial scans in the PARADIGM trial

J Cardiovasc Comput Tomogr. 2023 Nov-Dec;17(6):407-412. doi: 10.1016/j.jcct.2023.08.012. Epub 2023 Oct 3.


Background: Non-obstructing small coronary plaques may not be well recognized by expert readers during coronary computed tomography angiography (CCTA) evaluation. Recent developments in atherosclerosis imaging quantitative computed tomography (AI-QCT) enabled by machine learning allow for whole-heart coronary phenotyping of atherosclerosis, but its diagnostic role for detection of small plaques on CCTA is unknown.

Methods: We performed AI-QCT in patients who underwent serial CCTA in the multinational PARADIGM study. AI-QCT results were verified by a level III experienced reader, who was blinded to baseline and follow-up status of CCTA. This retrospective analysis aimed to characterize small plaques on baseline CCTA and evaluate their serial changes on follow-up imaging. Small plaques were defined as a total plaque volume <50 ​mm3.

Results: A total of 99 patients with 502 small plaques were included. The median total plaque volume was 6.8 ​mm3 (IQR 3.5-13.9 ​mm3), most of which was non-calcified (median 6.2 ​mm3; 2.9-12.3 ​mm3). The median age at the time of baseline CCTA was 61 years old and 63% were male. The mean interscan period was 3.8 ​± ​1.6 years. On follow-up CCTA, 437 (87%) plaques were present at the same location as small plaques on baseline CCTA; 72% were larger and 15% decreased in volume. The median total plaque volume and non-calcified plaque volume increased to 18.9 ​mm3 (IQR 8.3-45.2 ​mm3) and 13.8 ​mm3 (IQR 5.7-33.4 ​mm3), respectively, among plaques that persisted on follow-up CCTA. Small plaques no longer visualized on follow-up CCTA were significantly more likely to be of lower volume, shorter in length, non-calcified, and more distal in the coronary artery, as compared with plaques that persisted at follow-up.

Conclusion: In this retrospective analysis from the PARADIGM study, small plaques (<50 ​mm3) identified by AI-QCT persisted at the same location and were often larger on follow-up CCTA.

Keywords: Artificial intelligence; Atherosclerosis; Coronary; Coronary CT angiography; Small plaque.

MeSH terms

  • Atherosclerosis*
  • Computed Tomography Angiography / methods
  • Coronary Angiography / methods
  • Coronary Artery Disease* / diagnostic imaging
  • Female
  • Humans
  • Male
  • Middle Aged
  • Plaque, Atherosclerotic*
  • Predictive Value of Tests
  • Retrospective Studies
  • Tomography, X-Ray Computed / methods