Role of cardiac magnetic resonance imaging (CMR) in the evaluation of GUCH

Cardiac magnetic resonance imaging (CMR) has the advantage that it is less operator dependent than echocardiography regarding the acquisition of images. But when it comes to interpretation, experience does matter a lot in delineating the potential permutations and combinations possible in congenital heart disease. Three dimensional reconstruction enables better visualisation of the cardiac anatomy. Unlike echocardiography, CMR is not restricted by the echo window, which is often a limitation for the acquisition of echocardiographic data. But echocardiography is superior to CMR in estimating gradients and in detecting small highly mobile structures like vegetations. Quantification of ventricular volumes, ejection fractions and valvular regurgitations can be done by CMR. Evaluation of right ventricular volumes and ejection fraction are better done with CMR than echo because of the complex shape of the right ventricle. CMR is useful in the evaluation of right ventricle to pulmonary artery conduits, branch pulmonary arteries, aorta, systemic and pulmonary veins and collaterals. Detection and quantification of myocardial fibrosis with late gadolinium enhancement is another advantage of CMR. Tissue characterisation for fat and iron is also feasible with CMR. Though coronary anomalies can be detected by CMR, computerised tomographic (CT) angiography is superior for this purpose. Intracardiac and extra cardiac masses can be delineated well by CMR.