ORCID Profile
0000-0002-2422-9059
Current Organisation
Chang Gung University
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Elsevier BV
Date: 2019
Publisher: Elsevier BV
Date: 05-2005
DOI: 10.1016/J.MRI.2005.02.005
Abstract: The multishot echo planar imaging sequence was often used in the high-resolution diffusion measurements. However, it is susceptible to motion artifacts because of the requirements of combining the raw data from different acquisitions into one complete k-space data set. Conventional solutions used cardiac gating but greatly extended the total acquisition time. Here we propose a selective averaging algorithm based on the information in the navigator echoes. The data were s led continuously without cardiac gating. Contributions contaminated by motion were detected by a thresholding algorithm and were discarded during postprocessing. The data were then averaged in the modulus or complex format. Diffusion tensor imaging (DTI) data with isotropic spatial resolution were acquired in phantom as well as from two normal volunteers. The information in the navigator echoes proved to be a good indicator for the extent of motion contamination. Differences were noticed between modulus and complex averaging in DTI quantification, but both showed reduced artifact and improved signal-to-noise ratio.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 10-2008
Publisher: Wiley
Date: 26-05-2009
DOI: 10.1002/JMRI.21776
Abstract: To reduce the scan time of high angular resolution diffusion imaging (HARDI) by using the hemispherical encoding scheme with the cross-term correction. Unidirectional and 45 degrees crossing phantoms were built to evaluate the accuracy of the fiber orientation estimation when using a hemispherical encoding scheme with and without the cross-term correction. The q-ball imaging using the spherical harmonic basis was adopted for estimation of fiber orientation. By recalculating the diffusion gradient strengths, we make the actual b value in all directions equal to the expected b value for the correction of the cross-term. The separation angles measured on the crossing phantom are 42.67 degrees +/- 1.50 degrees , 42.75 degrees +/- 2.10 degrees , and 42.93 degrees +/- 2.78 degrees for cross-term-free results, for the results from the hemispherical encoding scheme with and without the cross-term correction. The angular errors in mapping the unidirectional phantom are 1.87 degrees -2.29 degrees and 4.01 degrees -4.92 degrees for the results using the hemispherical encoding scheme with and without correcting for the cross-term at different b values. Using the hemispherical encoding scheme with the cross-term correction can potentially halve the scan time of HARDI and obtain accurate fiber orientation estimation simultaneously. This will be helpful in the clinical application of HARDI.
Publisher: Wiley
Date: 26-03-2004
DOI: 10.1002/MRM.20012
Abstract: Diffusion tensor imaging (DTI) can provide vital insights into brain connectivity, and may become an important tool for the diagnosis and treatment of neurological disease. However, DTI's intrinsic low signal-to-noise ratio (SNR) and vulnerability to ghosting artifacts can result in poor image quality with low spatial resolution, which limits its clinical applications. In this study, a new double-shot EPI sequence (half-FOV EPI) with high spatial resolution was developed. This method enables DT measurements to be obtained with high isotropic spatial resolution and whole-brain coverage. To avoid ghosting artifacts, the data are combined in image space rather than in k-space.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Jiun-Jie Wang.