FLOW-SENSITIVE, FREQUENCY-INDEPENDENT EXCITATION OF MAGNETIC RESONANCE SIGNALS

摘要

A transmit coil system of a magnetic resonance system is exposed to high-frequency transmit pulses so that atomic nuclei of a predetermined type of atomic nucleus of an examination object introduced into an examination volume are excited by the high-frequency transmit pulses to emit magnetic resonance signals. A gradient magnetic system is exposed to gradient currents during the exposure of the examination volume to the high-frequency transmit pulses so that gradient magnetic fields are superimposed on a basic magnetic field generated by a basic magnet in the examination volume. The gradient currents and the high-frequency transmit pulses are matched to each other such that the atomic nuclei are exclusively those with a velocity lying within or outside a predetermined velocity range. The excitation is independent of variations in the Larmor frequency of the relevant type of atomic nucleus caused by inhomogeneities of the basic magnetic field and/or by chemical displacement.