Calcified coronary arteries pose a challenge to percutaneous coronary intervention (PCI). Calcium modification techniques (CMTs) increase procedural length, complexity and risk. Computed tomography coronary angiography (CTCA) is well suited to calcium identification and quantification and may offer valuable pre-procedural information. We hypothesised that CTCA could predict cases where CMT would be required during PCI. A single centre retrospective review (2021/2022) of consecutive patients who underwent PCI with a preceding CTCA demonstrating a calcified lesion in a major epicardial vessel. Blinded to the PCI strategy CTCA images were re-reviewed and calcium thickness, length, density and circumferential arc quantified. Receiver operating characteristic (ROC) curve for CMT defined optimum cut-off values. Calcium density (>
1000 HU) and calcific arc (>
180°) were proposed as a calcium planning score (CPS