ps2_soln - ECE 497E Homework 2 solutions. 1. Assume that in...

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ECE 497E Homework 2 solutions. 1. Assume that in a Fourier imaging experiment, the desired phase-encoding gradients are G n =n G 0 . What will happen to the reconstruced image if the gradient system malfunctions such that the effective gradients applied are: (a) G n =0 (b) G n =n( G 0 /2) (c) G n =n(2 G 0 ) (d) G n =n G 0 + δ G If Gn=0, then there is no phase encoding, so all the k-space lines have the same intensity: kx ky ifft2d If Gn is one half the desired value, then k will also be one-half. Since the field-of-view is inversely proportional to k, it will double. Since the object size is fixed, the image field- of-view will be twice the size of the object, effectively wasting half the image. If Gn is twice the desired value, then following the argument above, the field-of-view in the phase-encoding direction will have dimensions one-half those of the image, and so there will be a fold-back or aliasing artifact in the image. The effect of a constant gradient offset in the k-space data will not affect the field-of-view,
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This note was uploaded on 07/23/2008 for the course EE 497e taught by Professor Unknown during the Spring '08 term at Pennsylvania State University, University Park.

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ps2_soln - ECE 497E Homework 2 solutions. 1. Assume that in...

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