US Patent 8717022 Magnetic field gradient monitor apparatus and method

A method based on pure phase encode FIDs that permits high strength gradient measurement is disclosed. A small doped water phantom (1˜3 mm droplet, T1, T2, T2*<100 μs) within a microprobe is excited by a series of closely spaced broadband RF pulses each followed by single FID point acquisition. Two trial gradient waveforms illustrate the technique, neither of which could be measured by the conventional microprobe measurement. The first is an extended duration gradient waveform while the other illustrates this method's ability to measure gradient waveforms with large net area and/or high amplitude. This method is a point monitor with simple implementation and low cost hardware requirements.