The evaluation of ischaemic heart disease requires the measurement of regional and global ventricular function, identification of the presence and extent of myocardial ischaemia, visualisation of luminal narrowing of the coronary arteries and assessment of myocardial infarction (MI) and viability. Cardiovascular magnetic resonance imaging (MRI) has evolved over the last decade into a valuable tool for the diagnosis and management of a wide spectrum of cardiovascular disorders. It provides anatomical and functional information in acquired and congenital heart disease and is the most precise technique for the quantification of ventricular volumes, function and mass. Considerable technical and practice advances have been made since MRI was first introduced, and clinicians in the field are showing an unprecedented level of interest in it. MRI is noninvasive, has high spatial resolution and requires no potentially nephrotoxic contrast agent or radiation. It has been compared extensively with other established non-invasive imaging modalities such as electrocardiography (ECG) and nuclear cardiology (single photon emission computed tomography [SPECT]), and has been shown to be superior in many scenarios, particularly for the assessment of cardiac morphology and function.

Pathophysiological processes such as MI and ischaemia, stunning and hibernation and scarring and fibrosis can be identified easily using quick and simple protocols. Recently, late gadolinium-enhanced MRI and stress myocardial perfusion MRI have been shown to be useful in detecting infarct tissue and myocardial viability and in patient prognosis. We present here an overview of the role of MRI in interventional cardiology, distinguishing two groups of patients: those with known and those with unknown coronary artery disease (CAD).

Evaluation of Patients with Coronary Artery Disease
The evaluation of ischaemic heart disease requires the assessment of ventricular morphology and function, myocardial perfusion and viability and coronary flow reserve.

Myocardial Function
MRI is the ‘gold standard’ for quantifying ventricular volumes, ejection fraction and myocardial mass.¹ With ECG-gated and breathhold sequences, the development of steady-state free precession sequences has provided substantially improved blood/myocardial contrast on cine MR images in a reduced imaging time, allowing more accurate and reproducible delineation of the endocardial borders. MRI uses volumetric quantification based on Simpson’s rule. Endocardial and epicardial contours are drawn during post-processing, generating end-diastolic, end-systolic and stroke volumes, ejection fraction and myocardial mass. In contrast to planar imaging modalities (2D ECG and ventriculography), MRI provides more accurate left ventricular (LV) parameter values, especially when ventricular shape deviates from the assumed geometrical model, as in ischaemic or dilated cardiomyopathy (DCM),^2,3 and is the most reliable way to assess regional and global right ventricular (RV) function.⁴