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CHARACTERIZATION PHASE ERROR IN FAST SPIN ECHO SEQUENCES

IP.com Disclosure Number: IPCOM000239689D
Publication Date: 2014-Nov-25
Document File: 3 page(s) / 32K

Publishing Venue

The IP.com Prior Art Database

Abstract

The present invention proposes a technique to measure phase error resulting from eddy current effects and other effects separately in a fast spin echo (FSE) sequences. The technique includes a model to predict phase error based on gradient applied during imaging by measuring phase error directly. Therefore, there is no requirement of prescan for phase correction. When dominant phase error occurs from eddy current, the model to predict phase error is established by measuring phase error from given gradients. The invention utilizes four acquisitions. The first acquisition is carr-purcell-meiboom-gill (CPMG) FSE with conventional gradient. The second acquisition is carr–Purcell (CP) FSE with conventional gradient. The third acquisition is CPMG FSE with reversed gradient and the fourth acquisition is CP FSE with reverse gradient polarity.

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CHARACTERIZATION PHASE ERROR IN FAST SPIN ECHO SEQUENCES

FIELD OF INVENTION

The invention generally relates to fast spin echo sequences and more particularly to characterization of phase error in the fast echo sequences.

BACKGROUND OF THE INVENTION

A fast spin echo sequence plays an important role in clinical imaging. The fast spin echo sequences depend on carr-purcell-meiboom-gill (CPMG) condition and violation of the CPMG condition results in image artifacts. Main reason for violation of CPMG condition is eddy current effect. There is conjecture that vibration results in violation of CPMG condition. As a result, exact reason for phase error in the fast echo sequences is unknown.

 It would be desirable to have an efficient technique to measure phase error by other factors in the fast echo sequences.

BRIEF DESCRIPTION OF THE INVENTION

The present invention proposes a technique to measure phase error resulting from eddy current effects and other effects separately in fast spin echo (FSE) sequences. The technique includes a model to predict phase error based on gradient applied during imaging by measuring phase error directly. Therefore, there is no requirement of prescan for phase correction.

DETAILED DESCRIPTION OF THE INVENTION

The present invention proposes a technique to measure phase error resulting from eddy current effects and other effects separately in a fast spin echo (ESE) sequence.

The technique includes a model to predict phase error based on gradient applied during imaging by measuring phase error directly. Therefore, there is no requirement of prescan for phase correction. When dominant phase error occurs from eddy current, the model to predict phase error is established by measuring phase error from given gradients.

The invention utilizes four acquisitions. The first acquisition is carr-purcell-meiboom-gill (CPMG) FSE with conventional gradient. The second acquisition is carr–Purcell (CP) FSE with conventional gradient. The third acquisition is CPMG FSE with reversed gradient and the fourth acquisition is CP FSE with reverse gradient polarity. From the first and second acquisitions, total p...