Dynamic contrast-enhanced perfusion CMR

Dynamic contrast-enhanced perfusion cardiovascular magnetic resonance (CMR) visualizes the first passage of a peripherally injected contrast agent bolus through the left ventricle and myocardium. The presence and extent of myocardial ischaemia is assessed during vasodilation using adenosine or regadenoson and, in most cases, is repeated at rest. Contrast-enhanced perfusion CMR methods use electrocardiogram-gated fast T1-sensitive imaging to capture the signal changes during contrast agent passage with high temporal (every or every other heartbeat) and spatial (below 3 × 3 mm in-plane, up to submillimetre) resolution, allowing the detection of subendocardial ischaemia and microvascular disease. In clinical routine, perfusion CMR data are mostly visually interpreted but can also be analysed semi-quantitatively by describing or quantitatively. Perfusion CMR is highly accurate in detecting significant coronary artery stenoses. Combined with cine and late gadolinium enhancement imaging, it provides comprehensive assessment and risk stratification of patients with known or suspected coronary artery disease and is gaining an increasing role in international practice guidelines.

Early and late gadolinium enhancement

The peculiar features of gadolinium-chelated contrast agents and the development of contrast-enhanced inversion recovery technique in the late 1990s formed the basis of early and late gadolinium enhancement imaging, revolutionizing the application of magnetic resonance imaging in patients with cardiac diseases. Several clinical studies have indeed demonstrated the clinical benefits of early and late gadolinium enhancement imaging, including the discrimination between scarred/fibrotic myocardium and normal myocardium and the identification of mural thrombi and areas of microvascular obstruction among patients with acute myocardial infarction. The technique currently plays a key role in the differential diagnosis between cardiac diseases with ischaemic and non-ischaemic aetiology and in the assessment of patients with acute myocardial infarction and its complications. Due to its invaluable ability to provide diagnostic and prognostic information, it is indeed more frequently implemented for patients’ clinical management and decision-making. This chapter discusses the technical aspects of early and late gadolinium enhancement imaging, reviews the initial studies that led to the validation of the technique, and focuses on its application according to the main clinical syndromes (i.e. acute and chronic myocardial infarction, heart failure, conduction diseases, and ventricular arrhythmias). Guidelines for correct image acquisition and interpretation will be also provided, in particular, how to deal with patients with cardiac arrhythmias or with patients unable to breath-hold properly, and how to discriminate true late gadolinium enhancement areas from artefacts is discussed.