Automated unwrapping of MR phase images applied to BOLD MR-venography at 3 Tesla

J Magn Reson Imaging. 2003 Aug;18(2):175-80. doi: 10.1002/jmri.10346.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Algorithms
  • Brain / blood supply*
  • Brain / pathology
  • Brain Neoplasms / diagnosis*
  • Cerebral Veins / anatomy & histology*
  • Cerebral Veins / pathology*
  • Glioma / diagnosis*
  • Humans
  • Image Enhancement / methods
  • Image Processing, Computer-Assisted / methods
  • Magnetic Resonance Angiography / methods*
  • Magnetics
  • Middle Aged
  • Phlebography / methods
  • Reference Values