[MRI of the coronary arteries: possibilities and limits. A comparative presentation with reference to coronary angiography, echocardiography and electron beam tomography].

The depiction of coronary arteries with magnetic resonance angiography has become possible during the last few years. Powerful magnetic field gradients with short ramp times and improved RF components and pulse sequences, such as derivatives of FLASH and echoplanar imaging, have led to high expectations. Because spatial resolution is still restricted and the signal-to-noise ratio (SNR) limited as it cannot be increased easily, and because the data acquisition times are relatively long compared to the respiratory and cardiac cycle, the diagnostic value currently appears to be limited. Electron beam tomography constitutes an alternative to MRI. This computer tomographic method affords acquisition times of 50-100 ms with good SNR and high spatial resolution through deflection of an electron beam onto a ring anode and by using a stationary detector. Together with transoesphageal ultrasound, these non-invasive alternative methods for the depiction of coronary arteries are compared with the "gold standard" of conventional coronary angiography, and an overview of current results is given.