ACCELERATE-CMR: Accelerated Cardiovascular Magnetic Resonance for the Detection of Coronary Artery Disease - a Randomised Controlled Trial

Background and clinical context Coronary artery disease (CAD) remains one of the leading causes of morbidity and mortality worldwide and is responsible for a substantial burden of healthcare utilisation. Appropriate management depends upon accurately identifying patients with clinically significant disease while avoiding unnecessary invasive investigation in those without functionally important coronary artery disease. Consequently, contemporary clinical guidelines recommend non-invasive imaging as the initial investigation for many patients with suspected chronic coronary syndromes before consideration of invasive coronary angiography (ICA).

Although ICA remains the reference standard for defining coronary anatomy, it is invasive, costly, exposes patients to ionising radiation and carries a small but important risk of complications. Furthermore, anatomical stenosis alone does not reliably indicate whether a lesion causes myocardial ischaemia, and a substantial proportion of patients undergoing ICA do not subsequently require coronary revascularisation. These limitations have driven a shift towards non-invasive imaging strategies that more appropriately select patients for invasive investigation.

Stress cardiovascular magnetic resonance (CMR) has become an established non-invasive imaging modality for the assessment of suspected CAD. It combines assessment of myocardial perfusion, ventricular function and myocardial scar within a single examination without exposure to ionising radiation, allowing comprehensive evaluation of both ischaemic heart disease and alternative cardiac pathology. Multiple prospective studies and randomised trials have demonstrated excellent diagnostic performance and have established stress CMR as an effective gatekeeper to ICA, reducing unnecessary invasive procedures while maintaining excellent clinical outcomes.

Despite these advantages, access to stress CMR remains limited by finite scanner capacity and prolonged examination times. Conventional stress CMR protocols typically require 45-60 minutes, limiting scanner throughput and contributing to prolonged waiting times in many healthcare systems. Expansion of CMR capacity through additional scanners and workforce growth is resource intensive, highlighting the need for more efficient use of existing imaging infrastructure.

Recent advances in pulse sequence design, accelerated image acquisition and streamlined workflow have created an opportunity to redesign stress CMR examinations while preserving the diagnostic information required for routine clinical decision making. Rather than simply accelerating individual imaging sequences, these developments allow optimisation of the entire imaging pathway using contemporary real-time cine imaging, streamlined late gadolinium enhancement imaging and stress perfusion imaging. The resulting accelerated protocol substantially reduces scan duration while maintaining the comprehensive nature of the CMR examination.