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Numerically optimized radiofrequency pulses for robust and low-power cardiovascular T 2 preparation at 3T

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Application of the TR-FOCI adiabatic pulses in the phantoms and volunteers. a) Radial bSSFP image of the phantom with compartment T1 and T2 values that approach blood (bright center) and myocardium (darker outer layer). A HS8-derived TR-FOCI pulse with pulse energy 4Ws was used in the T2Prep. b) The same image, but with a 4Ws standard HS1 pulse. Distortions due to insufficient pulse energy can be clearly observed c) Contrast-to-noise ratio plots in the volunteers show that significantly less energy is required by the optimized pulses to obtain the same CNR. d) and e) In vivo human HS1-derived TR-FOCI image with T2Prep pulse energy ~4Ws: the superior performance of the optimized pulse compared to the standard HS1 pulse T2Prep can be clearly observed.
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Figure 2: Application of the TR-FOCI adiabatic pulses in the phantoms and volunteers. a) Radial bSSFP image of the phantom with compartment T1 and T2 values that approach blood (bright center) and myocardium (darker outer layer). A HS8-derived TR-FOCI pulse with pulse energy 4Ws was used in the T2Prep. b) The same image, but with a 4Ws standard HS1 pulse. Distortions due to insufficient pulse energy can be clearly observed c) Contrast-to-noise ratio plots in the volunteers show that significantly less energy is required by the optimized pulses to obtain the same CNR. d) and e) In vivo human HS1-derived TR-FOCI image with T2Prep pulse energy ~4Ws: the superior performance of the optimized pulse compared to the standard HS1 pulse T2Prep can be clearly observed.

Mentions: The optimized pulses demonstrated superior performance in the simulations compared to standard HSn pulses (Figure 1). The TR-FOCI pulses required 54% less power than the HS1 pulse to achieve artifact-free images and stable CNR (Figure 2), while images obtained with an HS8 pulse were never artifact-free. The optimized pulses needed roughly half the energy of the standard pulses, and the entire pulse sequence resulted in 20% less overall SAR deposition in the volunteers for artifact-free images with similar CNR as the original images.


Numerically optimized radiofrequency pulses for robust and low-power cardiovascular T 2 preparation at 3T
Application of the TR-FOCI adiabatic pulses in the phantoms and volunteers. a) Radial bSSFP image of the phantom with compartment T1 and T2 values that approach blood (bright center) and myocardium (darker outer layer). A HS8-derived TR-FOCI pulse with pulse energy 4Ws was used in the T2Prep. b) The same image, but with a 4Ws standard HS1 pulse. Distortions due to insufficient pulse energy can be clearly observed c) Contrast-to-noise ratio plots in the volunteers show that significantly less energy is required by the optimized pulses to obtain the same CNR. d) and e) In vivo human HS1-derived TR-FOCI image with T2Prep pulse energy ~4Ws: the superior performance of the optimized pulse compared to the standard HS1 pulse T2Prep can be clearly observed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4043734&req=5

Figure 2: Application of the TR-FOCI adiabatic pulses in the phantoms and volunteers. a) Radial bSSFP image of the phantom with compartment T1 and T2 values that approach blood (bright center) and myocardium (darker outer layer). A HS8-derived TR-FOCI pulse with pulse energy 4Ws was used in the T2Prep. b) The same image, but with a 4Ws standard HS1 pulse. Distortions due to insufficient pulse energy can be clearly observed c) Contrast-to-noise ratio plots in the volunteers show that significantly less energy is required by the optimized pulses to obtain the same CNR. d) and e) In vivo human HS1-derived TR-FOCI image with T2Prep pulse energy ~4Ws: the superior performance of the optimized pulse compared to the standard HS1 pulse T2Prep can be clearly observed.
Mentions: The optimized pulses demonstrated superior performance in the simulations compared to standard HSn pulses (Figure 1). The TR-FOCI pulses required 54% less power than the HS1 pulse to achieve artifact-free images and stable CNR (Figure 2), while images obtained with an HS8 pulse were never artifact-free. The optimized pulses needed roughly half the energy of the standard pulses, and the entire pulse sequence resulted in 20% less overall SAR deposition in the volunteers for artifact-free images with similar CNR as the original images.

View Article: PubMed Central - HTML

No MeSH data available.


Related in: MedlinePlus