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Multiple region MRI
Author(s) -
Nagle S.K.,
Levin D.N.
Publication year - 1999
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/(sici)1522-2594(199904)41:4<774::aid-mrm17>3.0.co;2-d
Subject(s) - k space , nyquist–shannon sampling theorem , fourier transform , sampling (signal processing) , image resolution , spatial frequency , field of view , real time mri , fourier analysis , computer science , computer vision , magnetic resonance imaging , artificial intelligence , mathematics , physics , optics , radiology , medicine , mathematical analysis , filter (signal processing)
Traditional Fourier MR imaging (FT MRI) utilizes the Whittaker‐Kotel'nikov‐Shannon (WKS) sampling theorem. This theorem specifies the spatial frequency components which need to be measured to reconstruct an image with a known field of view (FOV). In this paper, we generalize this result in order to find the optimal k‐space sampling for images that vanish except in multiple, possibly non‐adjacent regions within the FOV. This provides the basis for “multiple region MRI” (mrMRI), a method of producing such images from a fraction of the k‐space samples required by the WKS theorem. Image reconstruction does not suffer from noise amplification and can be performed rapidly with fast Fourier transforms, just as in conventional FT MRI. The mrMRI method can also be used to reconstruct images that have low spatial‐frequency components throughout the entire FOV and high spatial frequencies (i.e. edges) confined to multiple small regions. The greater efficiency of mrMRI sampling can be parlayed into increased temporal or spatial resolution whenever the imaged objects have signal or “edge” intensity confined to multiple small portions of the FOV. Possible areas of application include MR angiography (MRA), interventional MRI, functional MRI, and spectroscopic MRI. The technique is demonstrated by using it to acquire Gd‐enhanced first‐pass 3D MRA images of the carotid arteries without the use of bolus‐timing techniques. Magn Reson Med 41:774–786, 1999. © 1999 Wiley‐Liss, Inc.