Gallichan, Daniel ![]() |
Abstract
We have identified and studied a pronounced artifact in diffusion-weighted MRI on a clinical system. The artifact results from vibrations of the patient table due to low-frequency mechanical resonances of the system which are stimulated by the low-frequency gradient switching associated with the diffusion-weighting. The artifact manifests as localized signal-loss in images acquired with partial Fourier coverage when there is a strong component of the diffusion-gradient vector in the left–right direction. This signal loss is caused by local phase ramps in the image domain which shift the apparent k-space center for a particular voxel outside the covered region. The local signal loss masquerades as signal attenuation due to diffusion, severely disrupting the quantitative measures associated with diffusion-tensor imaging (DTI). We suggest a way to improve the interpretation of affected DTI data by including a co-regressor which accounts for the empirical response of regions affected by the artifact. We also demonstrate that the artifact may be avoided by acquiring full k-space data, and that subsequent increases in TE can be avoided by employing parallel acceleration.
Item Type: | Article |
---|---|
Date Type: | Publication |
Status: | Published |
Schools: | Cardiff University Brain Research Imaging Centre (CUBRIC) Engineering |
Subjects: | T Technology > TA Engineering (General). Civil engineering (General) |
Uncontrolled Keywords: | diffusion imaging; DTI; vibration; artifact |
Publisher: | Wiley-Blackwell |
ISSN: | 1065-9471 |
Date of Acceptance: | 11 June 2009 |
Last Modified: | 02 Nov 2022 10:22 |
URI: | https://orca.cardiff.ac.uk/id/eprint/98391 |
Citation Data
Cited 83 times in Scopus. View in Scopus. Powered By Scopus® Data
Actions (repository staff only)
![]() |
Edit Item |