. Author manuscript; available in PMC: 2008 Oct 27.

Published in final edited form as: Proc IEEE Inst Electr Electron Eng. 2003 Oct;9(10):1627–1648. doi: 10.1109/JPROC.2003.817872

Table 1.

A Quick Comparison of Different Motion Analysis Techniques That Are Unique to MRI

Feature	Phase Contrast MRI (PCMRI)	MR Tagging	Pulse Field Gradient (PFG) Methods: HARP, DENSE
Time Resolution	- Velocity-encoding pulses require 4ms in current scanners. - Phase difference calculation required (at least two acquisitions). - Time integration required for desplacement estimate.	- Simple tagging pulses take ∼3 ms in each direction. - Time resolution set by imaging method. - Tag pattern detection is very insensitive to motion.	- HARP: Multiphase acquisition is possible, time resolution is set by imaging method. - DENSE: Currently implemented only for a single phase.
Spatial Resolution	- Resolution is determined by the dimensiion of the derivative operator (two pixel) minimum and the SNR of the velocity induced phase shift.	- Limited by the density of tagging pattern.	- Limited by the spatial resolution of imagging method. - In general, higher spatial resolution with DENSE.
Acqusition Time	- Four acquisitions required for 3D deformations.	- Depends on method used: 1-3 acquisitions required for 3D deformation.	- Depends on method used: 1-3 acquisitions required for 3D deformation.
MRI Physics	- Phase shifts from other processes can interfere with velocity encoding. - Steady state must be maintained during acquisition. - Motion estimated can be obtained over the entire heart cycle.	- Tag fading from T1 recovery limits duration of motion tracking. - Tagging pattern detection is very robust to image artifacts. - Any imaging method can be used.	- T1 recovery limits the duration of motion tracking. - Dispersive effects of intravoxel dephasing are the main limitation.
Quantification and Visualization	- No segmentation required for quantitative estimates. - Strain cannot be viewed directly from the raw images. - Strain-rate computed directly from spatial gradients of velocity.	- 2D myocardial strain can be observed directly from the deformation patterns on the images.	- Allows direct quantification of displacement. - Segmentation not necessary. - Synthetic tags can be used.