NMR flow measurements using a gradient pulse and phase difference technique agreed with Doppler ultrasound for measuring flow velocities in the carotid and femoral arteries of 2 volunteers.
Can NMR imaging with a gradient pulse and phase difference technique accurately measure flow velocities compared to standard methods?
NMR imaging using a phase difference technique can accurately measure flow velocities, demonstrating potential clinical utility for vascular assessment.
A method for determining flow by nuclear magnetic resonance (NMR) imaging is described. A conventional spin-echo imaging sequence is employed with the addition of balanced gradient pulses on either side of the pi radiofrequency pulse. Flow velocities in the direction orthogonal to the image plane are determined by the phase shifts in the NMR image. Experimental validation of the technique in vitro was achieved with a phantom designed to give a continuous flow of water. The flow rate measured by NMR agreed well with the volume flow rate through the phantom. In vivo, NMR flow measurements on the carotid and femoral arteries of two volunteers were compared with Doppler ultrasound results. Velocity measurements were in general agreement. Rapid changes in flow are difficult to follow with the NMR method unless particular care is taken in gradient profile design. The technique can readily be used in existing NMR imaging machines and may have a useful clinical role.
Bryant et al. (1984) studied this question. NMR imaging using a gradient pulse and phase difference technique vs. Doppler ultrasound was evaluated on Flow velocity measurement agreement. NMR flow measurements using a gradient pulse and phase difference technique agreed with Doppler ultrasound for measuring flow velocities in the carotid and femoral arteries of 2 volunteers.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: