MULTILEVEL WAVELET-TRANSFORM ENCODING IN MRI

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