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Improved vessel visualization in MR angiography by nonlinear anisotropic filtering
Author(s) -
Orkisz Maciej M.,
Bresson Christine,
Magnin Isabelle E.,
Champin Olivier,
Douek Philippe C.
Publication year - 1997
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.1910370617
Subject(s) - maximum intensity projection , contrast (vision) , filter (signal processing) , artificial intelligence , computer vision , intensity (physics) , smoothing , computer science , noise reduction , orientation (vector space) , projection (relational algebra) , nonlinear system , visualization , visibility , magnetic resonance angiography , mathematics , magnetic resonance imaging , angiography , optics , physics , algorithm , radiology , medicine , geometry , quantum mechanics
This paper deals with a preprocessing technique of magnetic resonance angiography (MRA) images, applied before maximum‐intensity‐projection (MIP). The purpose was to recover small low‐intensity vessels, visible in individual slices, but lost in MIP images that usually have higher background level than the individual slices. The authors have developed a nonlinear three‐dimensional spatial filtering technique (called HD filter) based on anisotropic smoothing. The filter first searches for the local orientation of the vessel. It then performs a nonlinear smoothing in the vessel's local direction so as to avoid blurring its boundaries. Noise level reduction, contrast enhancement, and improved small vessel visibility achieved by this filter are illustrated on dynamic contrast‐enhanced subtraction MRA images of the lower limbs.