A New Tailored Sinc Pulse and Its Use for Multiband Pulse Design
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Purpose: Among RF pulses, a sinc pulse is typically used for slice selection due to itsfrequency-selective feature. When a sinc pulse is implemented in practice, it needs tobe apodized to avoid truncation artifacts at the expense of broadening the transitionregion of the excited-band profile. Here a sinc pulse tailored by a new apodizationfunction is proposed that produces a sharper transition region with well suppressionof truncation artifacts in comparison with conventional tailored sinc pulses. Amultiband pulse designed using this newly apodized sinc pulse is also suggestedinheriting the better performance of the newly apodized sinc pulse. Materials and Methods: A new apodization function is introduced to taper a sincpulse, playing a role to slightly shift the first zero-crossing of a tailored sinc pulsefrom the peak of the main lobe and thereby producing a narrower bandwidth aswell as a sharper pass-band in the excitation profile. The newly apodized sinc pulsewas also utilized to design a multiband pulse which inherits the performance ofits constituent. Performances of the proposed sinc pulse and the multiband pulsegenerated with it were demonstrated by Bloch simulation and phantom imaging. Results: In both simulations and experiments, the newly apodized sinc pulseyielded a narrower bandwidth and a sharper transition of the pass-band profilewith a desirable degree of side-lobe suppression than the commonly used Hanningwindowedsinc pulse. The multiband pulse designed using the newly apodized sincpulse also showed the better performance in multi-slice excitation than the onedesigned with the Hanning-windowed sinc pulse. Conclusion: The new tailored sinc pulse proposed here provides a better performancein slice (or slab) selection than conventional tailored sinc pulses. Thanks to theavailability of analytical expression, it can also be utilized for multiband pulsedesign with great flexibility and readiness in implementation, transferring its betterperformance.
Abstract
Purpose: Among RF pulses, a sinc pulse is typically used for slice selection due to itsfrequency-selective feature. When a sinc pulse is implemented in practice, it needs tobe apodized to avoid truncation artifacts at the expense of broadening the transitionregion of the excited-band profile. Here a sinc pulse tailored by a new apodizationfunction is proposed that produces a sharper transition region with well suppressionof truncation artifacts in comparison with conventional tailored sinc pulses. Amultiband pulse designed using this newly apodized sinc pulse is also suggestedinheriting the better performance of the newly apodized sinc pulse. Materials and Methods: A new apodization function is introduced to taper a sincpulse, playing a role to slightly shift the first zero-crossing of a tailored sinc pulsefrom the peak of the main lobe and thereby producing a narrower bandwidth aswell as a sharper pass-band in the excitation profile. The newly apodized sinc pulsewas also utilized to design a multiband pulse which inherits the performance ofits constituent. Performances of the proposed sinc pulse and the multiband pulsegenerated with it were demonstrated by Bloch simulation and phantom imaging. Results: In both simulations and experiments, the newly apodized sinc pulseyielded a narrower bandwidth and a sharper transition of the pass-band profilewith a desirable degree of side-lobe suppression than the commonly used Hanningwindowedsinc pulse. The multiband pulse designed using the newly apodized sincpulse also showed the better performance in multi-slice excitation than the onedesigned with the Hanning-windowed sinc pulse. Conclusion: The new tailored sinc pulse proposed here provides a better performancein slice (or slab) selection than conventional tailored sinc pulses. Thanks to theavailability of analytical expression, it can also be utilized for multiband pulsedesign with great flexibility and readiness in implementation, transferring its betterperformance.
참고문헌 (12)
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