Acoustic noise reduction in T 1- and proton-density-weighted turbo spin-echo imaging.
OBJECTIVE
To reduce acoustic noise levels in T 1-weighted and proton-density-weighted turbo spin-echo (TSE) sequences, which typically reach acoustic noise levels up to 100 dB(A) in clinical practice.


METHODS
Five acoustic noise reduction strategies were combined: (1) gradient ramps and shapes were changed from trapezoidal to triangular, (2) variable-encoding-time imaging was implemented to relax the phase-encoding gradient timing, (3) RF pulses were adapted to avoid the need for reversing the polarity of the slice-rewinding gradient, (4) readout bandwidth was increased to provide more time for gradient activity on other axes, (5) the number of slices per TR was reduced to limit the total gradient activity per unit time. We evaluated the influence of each measure on the acoustic noise level, and conducted in vivo measurements on a healthy volunteer. Sound recordings were taken for comparison.


RESULTS
An overall acoustic noise reduction of up to 16.8 dB(A) was obtained by the proposed strategies (1-4) and the acquisition of half the number of slices per TR only. Image quality in terms of SNR and CNR was found to be preserved.


CONCLUSIONS
The proposed measures in this study allowed a threefold reduction in the acoustic perception of T 1-weighted and proton-density-weighted TSE sequences compared to a standard TSE-acquisition. This could be achieved without visible degradation of image quality, showing the potential to improve patient comfort and scan acceptability.
Research Center for Magnetic-Resonance-Bavaria, Am Hubland, 97074, Würzburg, Germany. mott@physik.uni-wuerzburg.de.
Martin
M
Ott
Research Center for Magnetic-Resonance-Bavaria, Am Hubland, 97074, Würzburg, Germany.
Martin
M
Blaimer
Research Center for Magnetic-Resonance-Bavaria, Am Hubland, 97074, Würzburg, Germany.
Felix
F
Breuer
Siemens Healthcare, Erlangen, Germany.
David
D
Grodzki
Siemens Healthcare, Erlangen, Germany.
Björn
B
Heismann
Department of Experimental Physics 5, University of Wuerzburg, Würzburg, Germany.
Peter
P
Jakob
D000162:Acoustics; D016477:Artifacts; D001921:Brain / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009622:Noise; D011522:Protons; D059629:Signal-To-Noise Ratio
D011522:Protons
Acoustic noise reduction; Clinical sequence; Patient comfort; Patient compliance; Quiet MRI; TSE