Computed Tomography Angiography

The goal of this observational study is to learn if AI-assisted cardiac CT imaging can improve cardiovascular risk stratification and prediction of future coronary events in an adult population undergoing clinically indicated cardiac CT. The main questions it aims to answer are: * Can AI-enhanced cardiac CT accurately assess cardiovascular risk in a real-world adult population? * How do CT-derived plaque characteristics correlate with clinical, biochemical, and lifestyle risk factors? Researchers will compare subgroups (e.g., patients with different risk profiles, biomarkers, or imaging findings, and a subset undergoing OCT imaging) to see if differences in imaging and clinical parameters are associated with cardiovascular risk and plaque vulnerability. Participants will: * Provide informed consent and medical history/demographic information * Undergo blood sampling for cardiovascular and metabolic biomarkers * Have a resting ECG performed * Complete a detailed lifestyle and health questionnaire * Receive a non-invasive cardiac CT scan interpreted by an expert * Potentially receive heart rate-lowering medication (e.g., metoprolol) if required for imaging quality * Be referred for further clinical evaluation if clinically indicated 

A chronic total occlusion (CTO) is present in 15-20% of patients who are referred for invasive coronary angiography. CTO Percutaneous Coronary Intervention (PCI) procedure success rates have increased over the years and can be as high as 90% when performed by high-volume CTO operators.Procedurally, excess calcification in the CTO anatomy is one factor which makes it difficult to complete the procedure or obtain ideal stent expansion. Excess calcification is best identified by Computed Tomography Coronary Angiography (CTCA) rather than invasive angiography. The investigators plan to retrospectively evaluate CTCA in patients who underwent CTO PCI and correlate calcification characteristics with CTO PCI outcomes and tools utilised for calcium modification.