Water diffusion heterogeneity index in the human brain is insensitive to the orientation of applied magnetic field gradients. Magn Reson Med 2006 Aug;56(2):235-9
Date
08/25/2006Pubmed ID
16929466DOI
10.1002/mrm.20960Scopus ID
2-s2.0-33746725285 (requires institutional sign-in at Scopus site) 79 CitationsAbstract
The alpha diffusion-weighted imaging (DWI) method was developed to study heterogeneous water diffusion in the human brain using magnetic resonance imaging (MRI). An advantage of this model is that it does not require an assumption about the shape of the intravoxel distribution of apparent diffusion rates, and it has a calculable relationship to this distribution. The alpha-DWI technique is useful for detecting microstructural tissue changes associated with brain tumor invasion, and may be useful for directing therapy to invading tumor cells. In previous work, alpha-DWI was performed with magnetic field gradients applied along a single direction in order to avoid artificially introducing a source of heterogeneity to the decay. However, it is known that restricted diffusion is anisotropic in the brain, and the alpha-DWI method must take this into account to be complete. In this work the relationship between the applied magnetic field gradients and the fitted stretched-exponential model parameters was studied in the human brain. It was found the distributed diffusion coefficient (DDC) varies with the direction of applied gradients, while the heterogeneity index alpha is relatively direction-insensitive. It is proposed that in clinical use, maps of alpha can be created using diffusion-weighting gradients applied in a single direction that reflect the tissue heterogeneity.
Author List
Bennett KM, Hyde JS, Schmainda KMAuthor
Kathleen M. Schmainda PhD Professor in the Biophysics department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AlgorithmsAnisotropy
Body Water
Brain Chemistry
Brain Mapping
Brain Neoplasms
Cerebral Cortex
Diffusion Magnetic Resonance Imaging
Female
Humans
Male
