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. Materia ls and Methods: The technique employs Fourier phase encoding to encode the first component, and phase contrast detection to encode the secon d. Although the technique can be generalized to any number of spatial dimensions and motional orders, applications in which one or two spati al dimensions are obtained with a single Fourier velocity or accelerat ion dimension are most likely to be useful. For example, Fourier-encod ed velocity and phase-contrasted acceleration information can be combi ned into the same image. Results: Several variations of the pulse sequ ence were investigated in phantoms and human volunteers. The first var iation 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 a nother variation two spatial dimensions were acquired with a third dim ension that uses Fourier velocity encoding to measure axial velocity w ithin a curved tube. Radial velocity components were determined simult aneously with a second velocity-encoding gradient pulse. Conclusion: T he phantom and in vivo results presented here suggest that simultaneou s detection of two or more components of motion is feasible.