Medical College of Wisconsin
CTSIResearch InformaticsREDCap

Improving robustness and reliability of phase-sensitive fMRI analysis using temporal off-resonance alignment of single-echo timeseries (TOAST). Neuroimage 2009 Feb 01;44(3):742-52

Date

11/11/2008

Pubmed ID

18992826

Pubmed Central ID

PMC2884970

DOI

10.1016/j.neuroimage.2008.10.001

Scopus ID

2-s2.0-57649213868 (requires institutional sign-in at Scopus site)   30 Citations

Abstract

Echo Planar Imaging (EPI), often utilized in functional MRI (fMRI) experiments, is well known for its vulnerability to inconsistencies in the static magnetic field (B(0)). Correction for these field inhomogeneities usually involves measuring the magnetic field at a single time point, and using this static information to correct a series of images collected over the course of one or multiple experiments. However, common phenomena, such as respiration and motion, change the characteristics of the B(0) field homogeneity in a time-dependent and often unpredictable manner, rendering previous field measurements invalid. The effects of these changes are particularly large in the image phase, due to its direct and sensitive relationship to the magnetic field, and methods utilizing complex information can suffer enormously. This dependence can be exploited to estimate the temporal dynamics of the B(0) field. Use of this information to correct fMRI data can provide more effective motion correction, reduce temporal "noise," and can substantially restore statistically significant power to complex fMRI data analysis. All of the necessary information is embedded in complex EPI images, and results indicate this is a robust way to improve the quality of fMRI data, especially when used with complex analysis.

Author List

Hahn AD, Nencka AS, Rowe DB

Author

Andrew S. Nencka PhD Center Director, Professor in the Radiology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Algorithms
Artifacts
Brain
Brain Mapping
Echo-Planar Imaging
Evoked Potentials
Humans
Image Enhancement
Image Interpretation, Computer-Assisted
Magnetic Resonance Imaging
Reproducibility of Results
Sensitivity and Specificity