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Result : Searchterm 'Velocity Compensation' found in 1 term [ ] and 1 definition [ ], (+ 5 Boolean[ ] results
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| |  | | | • Share the entry 'Velocity Compensation': | | | | Further Reading: | Basics:
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Pulse sequences, designed to be insensitive to flow, e.g. at every even echo, a spin echo sequence is not flow sensitive. Velocity compensation is achieved by using gradients, which are either symmetrical around a 180° pulse and switched on twice as is the case for motion compensated spin echo pulse sequences, or two antisymmetrical gradient lobes without 180° pulse, which is the way to produce a velocity compensated gradient echo pulse sequence.
The signal of the second echo (and all other even echoes) is independent of the velocity of the object. Thus, velocity-based motion effects stemming from the entire voxel or from spins within a voxel (intravoxel incoherent motion) are suppressed with such pulse sequences.
If higher order motion is relevant, as it may be in turbulent jets across valves, acceleration and jerk effects can also be compensated for by the use of appropriate combinations of gradient- and radio frequency pulses.
With the increasingly stronger gradients, echo times in MR systems can be shortened to the point at which effects other than velocity effects hardly ever become relevant. |
| |  | | • View the DATABASE results for 'Motion Compensation Pulse Sequences' (2).
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| | | |  | | • View the DATABASE results for 'Flow Related Enhancement' (10).
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| |  | | • View the DATABASE results for 'Gradient Motion Rephasing' (2).
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| |  | | • View the DATABASE results for 'Flow Compensation' (14).
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|  | 1 - 5 (of 7) nextResult Pages : [1] [2] |
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