
doi: 10.1002/mrm.22549
pmid: 20597118
AbstractVariable‐rate selective excitation RF pulses modulate the slice selection gradients during RF transmission, especially to reduce the total RF power. Amplitude‐modulated slice selection gradients can lead to increased gradient noise, in particular in high‐field MRI where variable‐rate selective excitation techniques are often used. In this work, an algorithm is presented that calculates a variable‐rate selective excitation pulse modulation from given RF pulses with constant slice selection gradient. The algorithm avoids the known acoustic resonance frequencies of the gradient system to minimize sound pressure levels. It was tested with four different slice‐selective RF pulse shapes (Sinc, Gaussian, and two Shinnar‐LeRoux). Sound measurements revealed a reduction of the mean sound pressure level by up to 13dB, and simultaneously, the specific absorption rate was reduced by 55%. Magn Reson Med, 2010. © 2010 Wiley‐Liss, Inc.
Image Interpretation, Computer-Assisted, 610, Reproducibility of Results, Signal Processing, Computer-Assisted, Image Enhancement, Noise, Magnetic Resonance Imaging, Sensitivity and Specificity, Algorithms
Image Interpretation, Computer-Assisted, 610, Reproducibility of Results, Signal Processing, Computer-Assisted, Image Enhancement, Noise, Magnetic Resonance Imaging, Sensitivity and Specificity, Algorithms
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 10 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 10% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 10% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Average |
