A fast, analytically based method to optimize local transmit efficiency for a transmit array.

Abstract:

PURPOSE:To develop an analytically based algorithm for rapid optimization of the local radiofrequency magnetic (B1+) field intensity for a given radiofrequency power through a transmit array. The analytical nature of the method will yield insight to optimization requirements and provides a valuable reference for numerically based searches. METHODS:With the knowledge of the B1+ field distribution generated by each single coil of the array, both the phases and the amplitudes of each coil current are optimized to maximize the magnitude of the B1+ field in a specific location of the body per unit of power transmitted through the array and, consequently, minimizing the whole body specific absorption rate for a given pulse sequence. RESULTS:Simulations considering the human body show that the proposed method can reduce the whole-body specific absorption rate for a given B1+ magnitude at the location of interest by a factor of about 6.3 compared to the classic birdcage current configuration, and by a factor of 3.2 compared to phase-only shimming in a case with significant coupling between the elements of the array. CONCLUSION:The proposed method can rapidly provide valuable information pertinent to the optimization of field distributions from transmit arrays.

journal_name

Magn Reson Med

authors

Carluccio G,Collins CM,Erricolo D

doi

10.1002/mrm.24653

subject

Has Abstract

pub_date

2014-01-01 00:00:00

pages

432-9

issue

1

eissn

0740-3194

issn

1522-2594

journal_volume

71

pub_type

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