Coronary angiography has been the standard method for quantifying the severity of coronary artery stenosis, however its physiological relevance by angiography is imperfect. At present velocity-encoded cine phase contrast MRI is a non invasive technique that can provide accurate assessment of coronary flow volume and coronary flow reserve, validated in animal and human studies by Doppler flow measurement. MRI may be recognized as a comprehensive, widely available technique independent of any nuclear tracer or contrast media, for evaluation of the presence and physiological significance of a variety of heart diseases which compromise coronary flow reserve.