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Ultrashort echo time (UTE) imaging using gradient pre-equalization and compressed sensing.


Type

Article

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Authors

Fabich, Hilary T 
Sederman, Andrew J 
Holland, Daniel J 

Abstract

Ultrashort echo time (UTE) imaging is a well-known technique used in medical MRI, however, the implementation of the sequence remains non-trivial. This paper introduces UTE for non-medical applications and outlines a method for the implementation of UTE to enable accurate slice selection and short acquisition times. Slice selection in UTE requires fast, accurate switching of the gradient and r.f. pulses. Here a gradient "pre-equalization" technique is used to optimize the gradient switching and achieve an effective echo time of 10μs. In order to minimize the echo time, k-space is sampled radially. A compressed sensing approach is used to minimize the total acquisition time. Using the corrections for slice selection and acquisition along with novel image reconstruction techniques, UTE is shown to be a viable method to study samples of cork and rubber with a shorter signal lifetime than can typically be measured. Further, the compressed sensing image reconstruction algorithm is shown to provide accurate images of the samples with as little as 12.5% of the full k-space data set, potentially permitting real time imaging of short T2(*) materials.

Description

Keywords

Compressed sensing, Gradient pre-equalization, MRI, UTE, Ultrashort echo time

Journal Title

J Magn Reson

Conference Name

Journal ISSN

1090-7807
1096-0856

Volume Title

Publisher

Elsevier BV
Sponsorship
Engineering and Physical Sciences Research Council (EP/F047991/1)
Engineering and Physical Sciences Research Council (EP/K008218/1)
Engineering and Physical Sciences Research Council (EP/K039318/1)
HTF would like to acknowledge the financial support of the Gates-Cambridge Trust and all authors of the EPSRC (EP/K008218/1). In addition, we would like to thank SoftPoint Industries Inc. for providing samples of rubber.