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J Magn Reson Imaging. 1996 May-Jun;6(3):529-40.

Multilevel wavelet-transform encoding in MRI.

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Department of Medical Biophysics, University of Toronto, Sunnybrook Health Science Center (Imaging Research), Ontario, Canada.


This paper explores an alternative to standard Fourier MRI called wavelet-transform encoding. Spatially selective radiofrequency (RF) pulses are used to excite slice profiles in the shape of the wavelet-basis functions of a discrete wavelet transform. Our implementation on a standard commercial whole body MRI system resolves one spatial dimension through wavelet encoding and orthogonal directions through conventional frequency encoding and rectangular-slice selection. The wavelet transform is described as a method for multiresolution analysis, and we show how a high resolution MR image can be constructed from lower resolution images, representing the approximation and detail structures of the object. A multiple level architecture of the wavelet reconstruction is described, thereby allowing wavelet-encoded images to be reconstructed through several modes. Multilevel wavelet-encoded images of a gel phantom are presented that show comparable image quality to Fourier-encoded images of similar signal-to-noise ratio. However, a chemical-shift artifact is identified with this particular implementation.

[Indexed for MEDLINE]

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