Journal
JOURNAL OF MAGNETIC RESONANCE IMAGING
Volume 32, Issue 3, Pages 663-676Publisher
WILEY
DOI: 10.1002/jmri.22276
Keywords
susceptibility weighted imaging; susceptibility mapping; oxygen saturation; iron measurements
Funding
- National Institutes of Health [NHLBI R01HL062983-A4]
Ask authors/readers for more resources
Purpose: To create an orientation-independent, 3D reconstruction of the veins in the brain using susceptibility mapping. Materials and Methods: High-resolution, high-pass filtered phase images usually used for susceptibility weighted imaging (SW!) were used as a source for local magnetic field behavior. These images were subsequently postprocessed using an inverse procedure to generate susceptibility maps of the veins. Regularization and interpolation of the data in k-space of the phase images were used to reduce reconstruction artifacts. To understand the effects of artifacts, and to fine-tune the methodology, simulations of blood vessels were performed with and without noise. Results: With sufficient resolution, major veins in the brain could be visualized with this approach. The usual geometry-dependent phase dipole effects are removed by this processing, leaving basically images of the veins. Different sized vessels show a different level of contrast depending on their partial volume effects. Vessels that are 8 mm or 16 mm in size show quantitative values expected for normal oxygen saturation levels. Smaller vessels show smaller values due to errors in the methodology and due to partial volume effects. Larger vessels show a bias toward a reduced susceptibility approaching 90% of the expected value. Limitations of the method and artifacts related to different sources of errors are demonstrated. Conclusion: Susceptibility maps can successfully create venograms of the brain with varying levels of contrast-to-noise depending on the size of the vessel. Partial volume effects render this approach more useful as an imaging tool or a visualization tool, although certain larger vessels have measured susceptibilities close to expected values associated with normal blood oxygen saturation levels.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available