SIMULTANEOUS DETECTION OF MULTIPLE COMPONENTS OF MOTION WITH MRI

Objective: Simultaneous detection of two or more components of motion using new magnetic resonance pulse sequences was investigated. Materials and Methods: The technique employs Fourier phase encoding to encode the first component, and phase contrast detection to encode the second. Although the technique can be generalized to any number of spatial dimensions and motional orders, applications in which one or two spatial dimensions are obtained with a single Fourier velocity or acceleration dimension are most likely to be useful. For example, Fourier-encoded velocity and phase-contrasted acceleration information can be combined into the same image. Results: Several variations of the pulse sequence were investigated in phantoms and human volunteers. The first variation acquired images having an appearance similar to that of Fourier velocity-encoded images in which signal displacement is proportional to velocity, but with pixel intensity determined by acceleration. In another variation two spatial dimensions were acquired with a third dimension that uses Fourier velocity encoding to measure axial velocity within a curved tube. Radial velocity components were determined simultaneously with a second velocity-encoding gradient pulse. Conclusion: The phantom and in vivo results presented here suggest that simultaneous detection of two or more components of motion is feasible.