Imaging of the coronary arteries using magnetic resonance angiography

Magnetic resonance imaging of the coronary arteries is difficult due to the tortuous course of these vessels, their small diameter, and their rapid mo vement caused by respiration and cardiac contraction. Initial investigation s could demonstrate the feasability of non-invasive magnetic resonance coro nary angiography using 2-dimensional turbo-FLASH gradient-echo sequences in repeated breathholds of approximately 16 heart beats duration. Further dev elopments, especially the design of navigator-echo-based respiratory gated 3-dimensional imaging sequences, permitted the acquisition of contiguous vo lume data sets of the heart which eliminated many limitations of 2-dimensio nal repeated breath-hold sequences. With a spatial resolution of approximat ely 1.2 x 1.2 x 2 mm and a temporal resolution of approximately 126 ms: sev eral authors reported sensitivities of 70-80 % and specificities of approxi mately 90 % for the detection of coronary artery stenoses. Further improvem ents can be expected from new, intravascular contrast agents and from ultra fast sequences which permit acquisition of a sufficiently large imaging vol ume within one single breathhold.