Gradient rotating outer volume excitation (GROOVE): A novel method for single-shot two-dimensional outer volume suppression.
OBJECTIVE
To introduce a new outer volume suppression (OVS) technique that uses a single pulse and rotating gradients to accomplish frequency-swept excitation. This new technique, which is called gradient rotating outer volume excitation (GROOVE), produces a circular or elliptical suppression band rather than suppressing the entire outer volume.


METHODS
Theoretical and k-space descriptions of GROOVE are provided. The properties of GROOVE were investigated with simulations, phantom, and human experiments performed using a 4T horizontal bore magnet equipped with a TEM coil.


RESULTS
Similar suppression performance was obtained in phantom and human brain using GROOVE with circular and elliptical shapes. Simulations indicate that GROOVE requires less SAR and time than traditional OVS schemes, but traditional schemes provide a sharper transition zone and less residual signal.


CONCLUSIONS
GROOVE represents a new way of performing OVS in which spins are excited temporally in space on a trajectory that can be tailored to fit the shape of the suppression region. In addition, GROOVE is capable of suppressing tailored regions of space with more flexibility and in a shorter period of time than conventional methods. GROOVE provides a fast, low SAR alternative to conventional OVS methods in some applications (e.g., scalp suppression).
Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA.|Graduate Program in Neuroscience, University of Minnesota, Minneapolis, Minnesota, USA.
Nathaniel J
NJ
Powell
Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA.|Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
Albert
A
Jang
Department of Biomedical Engineering, Research Institute of Biomedical Engineering, College of Biomedical and Health Science, Konkuk University, Chungju, South Korea.
Jang-Yeon
JY
Park
Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA.|Commissariat à l'Energie Atomique, Molecular Imaging Research Center, Fontenay-aux-Roses, France.
Julien
J
Valette
Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA.
Michael
M
Garwood
Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, Minnesota, USA.
Małgorzata
M
Marjańska
D000465:Algorithms; D016477:Artifacts; D001921:Brain / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012535:Scalp / Q000033:anatomy & histology; D012680:Sensitivity and Specificity; D013382:Subtraction Technique
MRI methodologies; frequency-swept pulse; outer volume suppression