Mixed-bandwidth acquisitions: signal-to-noise ratio and signal-to-noise efficiency.
OBJECTIVE
To evaluate signal-to-noise ratio (SNR) and SNR efficiency in mixed-bandwidth acquisition (MBA). SNR efficiency describes the achievable SNR per unit time and is a basic aspect in clinical applications to optimize work flow.


METHODS
Corresponding simulations were performed and predictions of the theory verified in phantom experiments and volunteers. Specifically, SNR and SNR efficiencies were compared for an MBA fast low-angle shot (MBA-FLASH) sequence and traditional single-bandwidth acquisitions.


RESULTS
MBAs result in an SNR penalty compared to single-bandwidth acquisitions for a given sampling time. Furthermore, the nonuniform distribution of noise characteristics in k-space introduced by MBA sequences caused potential changes in noise texture of the image.


CONCLUSIONS
Overall, the MBA-FLASH imaging experiments in phantoms and healthy volunteers support the feasibility of using dual or multiple bandwidth acquisitions, which may be important in alternative imaging schemes that combine multiple acquisition techniques.
Choli
Morwan
M
Research Center for Magnetic Resonance Bavaria e.V. (MRB), Wuerzburg, Germany. choli@mr-bavaria.de
Jakob
Peter M
PM
Loeffler
Ralf B
RB
Hillenbrand
Claudia M
CM
D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D003198:Computer Simulation; D005583:Fourier Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D015233:Models, Statistical; D019047:Phantoms, Imaging; D015203:Reproducibility of Results