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Spiral Balanced FFE Disclosure Number: IPCOM000007385D
Publication Date: 2002-Mar-20
Document File: 1 page(s) / 52K

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Spiral Balanced FFE

MR-imaging involves fully balanced gradient surfaces in all directions. This provides

effective inherent flow compensation. This type of MR-imaging leads to good results in

cardiac, spine and abdominal imaging. A problem in fully balanced imaging is to avoid

phase-errors due to off-resonance effects when echo-shifting is applied.

Read-out is performed by spiral scanning of k-space and the gradient shape is adapted

so as to maintain the balanced surfaces. E.g. a start-up gradient phase is introduced to

maintain flow-compensation.

In particular, a spiral-in; spiral-out gradient waveform is sued where the 'start-up'

gradient shape is optimised to maintain flow-compensation behaviour at both the RF-pulses

and in central k-space. two reconstruction strategies can be chosen:

All acquisition time is used as a single echo image where the gradient samples pre- and post

TE are considered as two interlaced interleaves of the spiral trajectories. Or, the post- and pre-

TE signals are reconstructed separately t obtain a dual echo image.

Inherent flow-compensation is maintained, while phase-errors are more effectively

avoided as compared to e.g. an EPI-sequence. Moreover, the repetition time can even further

reduced as compared to e.g. and a B-FFE/EPI sequence.

Disclosed anonymously.