Assessment of data acquisition parameters, and analysis techniques for noise reduction in spinal cord fMRI data

Abstract Purpose The purpose of this work is to characterize the noise in spinal cord functional MRI, assess current methods aimed at reducing noise, and optimize imaging parameters. Methods Functional MRI data were acquired at multiple echo times and the contrast-to-noise ratio (CNR) was calculated...

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Bibliographic Details
Published in:Magnetic resonance imaging 2014-06, Vol.32 (5), p.473-481
Main Authors: Bosma, R.L, Stroman, P.W
Format: Article
Language:English
Subjects:
Algorithms
Brainstem
Contrast-to-noise
False positives
Female
fMRI
Humans
Image Enhancement - methods
Image Interpretation, Computer-Assisted - methods
Magnetic Resonance Imaging - methods
Male
Neural Pathways - physiology
Normalization
Pain Perception - physiology
Pain Threshold - physiology
Radiology
Reproducibility of Results
Sensitivity and Specificity
Signal-To-Noise Ratio
Spinal cord
Spinal Cord - physiology
Young Adult
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Summary:Abstract Purpose The purpose of this work is to characterize the noise in spinal cord functional MRI, assess current methods aimed at reducing noise, and optimize imaging parameters. Methods Functional MRI data were acquired at multiple echo times and the contrast-to-noise ratio (CNR) was calculated. Independently, the repetition time was systematically varied with and without parallel imaging, to maximize BOLD sensitivity and minimize type I errors. Noise in the images was characterized by examining the frequency spectrum, and investigating whether autocorrelations exist. The efficacy of several physiological noise reduction methods in both null (no stimuli) and task (thermal pain paradigm) data was also assessed. Finally, our previous normalization methods were extended. Results The echo time with the highest functional CNR at 3 Tesla is at roughly 75 msec. Parallel imaging reduced the variance and the presence of autocorrelations, however the BOLD response in task data was more robust in data acquired without parallel imaging. Model-free based approaches further increased the detection of active voxels in the task data. Finally, inter-subject registration was improved. Conclusions Results from this study provide a rigorous characterization of the properties of the noise and assessment of data acquisition and analysis methods for spinal cord and brainstem fMRI.
ISSN:0730-725X
1873-5894
DOI:10.1016/j.mri.2014.01.007