Abstract
Recently, theoretical and experimental work has shown that parallel transmission of RF pulses can be used to shorten the duration of multidimensional spatially-selective pulses and compensate for B1 field inhomogeneity. However, all the existing noniterative methods can design only excitation pulses for parallel transmission with a small flip angle (e.g., 30°, or at most 90°) and cannot design large-tip-angle inversion/refocusing pulses, because these methods are based on the small-tip-angle (STA) approximation of the Bloch equation. In this work, a method to design large-tip-angle multidimensional spatially-selective pulses for parallel transmission is proposed, based on an extension of the single-channel linear-class large-tip-angle (LCLTA) theory. Design examples of 2D refocusing and inversion parallel transmit pulses and magnetization profiles from Bloch equation simulations demonstrate the strength of the proposed method. A 2D spin-echo parallel transmission experiment on a slab phantom using a 180° refocusing pulse with an eight-channel transmit-only array further validates the effectiveness of the proposed method.
Original language | English (US) |
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Pages (from-to) | 326-334 |
Number of pages | 9 |
Journal | Magnetic Resonance in Medicine |
Volume | 58 |
Issue number | 2 |
DOIs | |
State | Published - Aug 2007 |
Keywords
- Multidimensional pulse
- Parallel transmission
- RF pulse
- SENSE
- Transmit sensitivity encoding
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology