[Principles of magnetic resonance angiography].

Abstract

Magnetic resonance angiography is a modality of functional imaging which can only be interpreted on the basis of a good understanding of vascular physiology and the physical principles of image acquisition. Magnetic resonance angiography is based on flow-related "artefacts". The oldest method is based on renewal of the image by proton flow: the flight time effect. Dephasing of the protons travelling in magnetic field gradients results in phase-contrast angiography. These two methods of angiography each have respective advantages and disadvantages: they are not mutually exclusive, but complementary.