Small field of view imaging using wavelet encoding with 2 dimensional RF pulses and gradient echo: phantom results.
OBJECTIVE
The objective of this work is to propose an imaging sequence based upon the wavelet encoding approach to provide MRI images free from folding artifacts, in the small field of view (FOV) regime, such as dynamic magnetic resonance imaging (MRI) studies.


METHODS
The method consists of using a 2D spatially selective RF excitation pulse inserted into a gradient- echo pulse sequence to excite spins within a determined plane where wavelet encoding is achieved in one direction and slice selection is performed in the second direction. Wavelet encoding allows for spatially localized excitation and consequently restricts the spins excited within a reduced FOV. It consists of varying, according to a predetermined scheme, the width and position of the profile of the so-called fast RF pulse of the 2D RF excitation pulse, to obey wavelet encoding translation and dilation conditions. This sequence is implemented on a 3 Tesla whole body Siemens scanner.


RESULTS
Compared to Fourier encoding, the proposed technique tested on phantoms with different shapes and structures, is able to provide gradient-echo reduced FOV images free from aliased signals.


CONCLUSIONS
Wavelet encoding is suitable for small FOV imaging in dynamic MRI studies.
Serrai
Hacene
H
National Research Council of Canada, Institute for Biodiagnostics, 435 Ellice Avenue, Winnipeg, MB, R3X 2C6, Canada. Hacene.Serrai@cnrc-nrc.gc.ca
Young
Richard
R
D016477:Artifacts; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D019047:Phantoms, Imaging; D011846:Radio Waves; D013113:Spin Labels; D051598:Whole Body Imaging
D013113:Spin Labels