A specific absorption rate reduction method for simultaneous multislice magnetic resonance imaging
This study proposes a modified Shinnar–Le Roux method to synthesize the excitation radio frequency (RF) pulse for a 2D gradient echo (GRE) based simultaneous multi-slice (SMS) magnetic resonance imaging (MRI) with features of low specific absorption rate (SAR) and small out-of-slice ripple. This syn...
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Veröffentlicht in: | Review of scientific instruments 2017-04, Vol.88 (4), p.043701-043701 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | This study proposes a modified Shinnar–Le Roux method to synthesize the excitation radio
frequency (RF)
pulse for a 2D gradient echo (GRE) based simultaneous multi-slice (SMS) magnetic resonance
imaging (MRI) with features of low specific absorption rate (SAR) and small out-of-slice
ripple. This synthesis method for SMS RF pulses employs thinner slice bandwidth and lower
multislice offset frequencies to reduce SAR values and adopts a weighted Parks–McClellan
algorithm to reduce sidelobes. Formulas for estimating relative SAR values of the SMS
pulses are also introduced. Relative SAR values and out-of-slice ripples of the proposed
and typical RF
pulses with different parameters are presented. In simultaneous 5-slice phantom and
3-slice human brain
imaging,
SMS pulses synthesized with the proposed method achieve 32% and 28% SAR values of standard
pulses while providing similar image qualities. Typical RF pulses such as sinc x cos
can also take advantage of the proposed method and offer lower SAR values for SMS
imaging.
The RF pulse
synthesized using the proposed method features low SAR, small sidelobes, and consistent
image
quality for 2D GRE-based SMS MRI. This method is applicable to the synthesis of typical
SMS RF pulses for
significant SAR reduction. |
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ISSN: | 0034-6748 1089-7623 |
DOI: | 10.1063/1.4979861 |