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 Medjournal_title
Magnetic resonance in medicineauthors
Carluccio G,Collins CM,Erricolo Ddoi
10.1002/mrm.24653subject
Has Abstractpub_date
2014-01-01 00:00:00pages
432-9issue
1eissn
0740-3194issn
1522-2594journal_volume
71pub_type
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