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MAGMA. 2015 Oct;28(5):485-92. doi: 10.1007/s10334-015-0483-6. Epub 2015 Apr 18.

Physiological noise in human cerebellar fMRI.

Author information

1
Centre d'Imagerie Biomédicale (CIBM), Station 6, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland. Wietske.vanderzwaag@epfl.ch.
2
Centre d'Imagerie Biomédicale (CIBM), Station 6, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland.
3
Instituto Superior Técnico, Lisbon, Portugal.
4
Department of Radiology, Université de Lausanne, Lausanne, Switzerland.

Abstract

OBJECTIVES:

To compare physiological noise contributions in cerebellar and cerebral regions of interest in high-resolution functional magnetic resonance imaging (fMRI) data acquired at 7T, to estimate the need for physiological noise removal in cerebellar fMRI.

MATERIALS AND METHODS:

Signal fluctuations in high resolution (1 mm isotropic) 7T fMRI data were attributed to one of the following categories: task-induced BOLD changes, slow drift, signal changes correlated with the cardiac and respiratory cycles, signal changes related to the cardiac rate and respiratory volume per unit of time or other. [Formula: see text] values for all categories were compared across regions of interest.

RESULTS:

In this high-resolution data, signal fluctuations related to the phase of the cardiac cycle and cardiac rate were shown to be significant, but comparable between cerebellar and cerebral regions of interest. However, respiratory related signal fluctuations were increased in the cerebellar regions, with explained variances that were up to 80 % higher than for the primary motor cortex region.

CONCLUSION:

Even at a millimetre spatial resolution, significant correlations with both cardiac and respiratory RETROICOR components were found in all healthy volunteer data. Therefore, physiological noise correction is highly likely to improve the temporal signal-to-noise ratio (SNR) for cerebellar fMRI at 7T, even at high spatial resolution.

KEYWORDS:

3D-EPI; Cerebellum; Magnetic resonance imaging; Noise; Resolution

PMID:
25894812
DOI:
10.1007/s10334-015-0483-6
[Indexed for MEDLINE]

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