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Commutator filter: A novel technique for the identification of structures producing significant susceptibility inhomogeneities and its application to functional MRI
Author(s) -
Lai Song,
Reichenbach Jürgen R.,
Haacke E. Mark
Publication year - 1996
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910360518
Subject(s) - identification (biology) , commutator , nuclear magnetic resonance , filter (signal processing) , computer science , biological system , physics , mathematics , biology , computer vision , pure mathematics , algebra over a field , lie conformal algebra , botany
A robust postprocessing method to detect regions of magnetic field change is presented. High resolution gradient echo data is acquired to create a complex baseline image. From this image, two low resolution images are obtained by applying a low pass filter on the magnitude image and the complex image, respectively. Subtraction of the magnitude of the filtered complex image from the filtered magnitude image gives a new image called a commutator image in which regions of susceptibility‐induced field variation are greatly enhanced. Results on phantoms and applications to visualize paramagnetic venous blood vessels in the human brain are presented. The use of this technique on a 3D gradient echo data set represents a new approach to obtain an MR venogram. The application of this method to blood oxygenation level dependent (BOLD) functional brain MR imaging is demonstrated and the important role susceptibility plays in this model is verified.