Cardiovascular disease remains the leading cause of death worldwide. Identifying individual patients at risk of a suture adverse events, including myocardial infractions (heart attacks), remains a major diagnostic challenge. Recent studies have shown that coronary plaques responsible for hear attack are composed of a large lipid core with a thin overlying fibrous cap. Although these features can be identified using invasive imaging modalities, non-invasive imaging options remain limited due to their poor spatial resolution. Recently the investigators have developed and validated a novel tool that will allow us to characterise coronary plaque composition based on dual source CT images. Our aim is to assess this tool within a cohort of patients who have already undergone a coronary CT as part of a previous study.