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Automated unwrapping of MR phase images applied to BOLD MR‐venography at 3 Tesla
Author(s) -
Rauscher Alexander,
Barth Markus,
Reichenbach Jürgen R.,
Stollberger Rudolf,
Moser Ewald
Publication year - 2003
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.10346
Subject(s) - venography , gradient echo , radiology , computer science , fast spin echo , nuclear medicine , visualization , electromagnetic coil , artificial intelligence , magnetic resonance imaging , physics , medicine , surgery , quantum mechanics , thrombosis
Purpose: To improve the diagnostic value of BOLD MR‐Venography by removing artifacts related to phase wrapping, particularly in regions of large background susceptibilities at high magnetic field strengths. Materials and Methods: High resolution, T 2 * ‐weighted, single echo images were acquired on a 3 T system (Medspec 30/80 Avance, Bruker Medical, Ettlingen, Germany) with a three‐dimensional, first order velocity compensated gradient echo sequence using a quadrature transmit/receive birdcage head coil. Data of nine healthy subjects and 19 patients were evaluated (age range: 27 to 76 years). To achieve improved MR‐venograms, a fully automated region‐growing phase unwrapping algorithm and subsequent high pass filtering were applied to phase images prior to the computation of minimum intensity projections. Results: Considerably improved visualization of venous structures in regions of large background susceptibility‐induced field inhomogeneities is demonstrated in healthy subjects and patients with brain tumors. Conclusion: BOLD MR venograms are improved compared to previous post‐processing algorithms. It is now feasible to obtain high‐resolution images also in inhomogeneous regions, which increases the clinical potential of BOLD MR‐Venography. J. Magn. Reson. Imaging 2003;18:175–180. © 2003 Wiley‐Liss, Inc.