Dehghani H, Oghabian M A, Batouli S A H, Arab Kheradmand J, Khatibi A. Effect of Physiological Noise on Thoracolumbar Spinal Cord Functional Magnetic Resonance Imaging in 3T Magnetic Field. BCN 2020; 11 (6) :737-752
URL:
http://bcn.iums.ac.ir/article-1-1236-en.html
1- Department of Medical Physics and Biomedical Engineering, Faculty of Medicine, Tehran University of Medical Science, Tehran, Iran.
2- Neuro Imaging and Analysis Group (NIAG), Research Center for Molecular and Cellular Imaging (RCMCI), Tehran University of Medical Sciences, Tehran, Iran.
3- Shefa Neuroscience Research Center, Tehran University of Medical Sciences, Tehran, Iran.
4- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, United Kingdom.
Abstract:
Introduction: Functional magnetic resonance imaging (fMRI) methods have been used to study sensorimotor processing in the spinal cord. However, these techniques confront unwanted noises to the measured signal from the physiological fluctuations. In the spinal cord imaging, most of the challenges are consequences of cardiac and respiratory movement artifacts that are considered as significant sources of noise, especially in the thoracolumbar region. In this study, we investigated the effect of each source of physiological noise and their contribution to the outcome of the analysis of the blood-oxygen-level-dependent signal in the human thoracolumbar spinal cord.
Methods: Fifteen young healthy male volunteers participated in the study, and pain stimuli were delivered on the L5 dermatome between the two malleoli. Respiratory and cardiac signals were recorded during the imaging session, and the generated respiration and cardiac regressors were included in the general linear model for quantification of the effect of each of them on the task-analysis results. The sum of active voxels of the clusters was calculated in the spinal cord in three correction states (respiration correction only, cardiac correction only, and respiration and cardiac noise corrections) and analyzed with analysis of variance statistical test and receiver operating characteristic curve.
Results: The results illustrated that cardiac noise correction had an effective role in increasing the active voxels (Mean±SD= 23.46±9.46) compared to other noise correction methods. Cardiac effects were higher than other physiological noise sources
Conclusion: In summary, our results indicate great respiration effects on the lumbar and thoracolumbar spinal cord fMRI, and its contribution to the heartbeat effect can be a significant variable in the individual fMRI data analysis. Displacement of the spinal cord and the effects of this noise in the thoracolumbar and lumbar spinal cord fMRI results are significant and cannot be ignored.
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● Respiration and heartbeat as physiological functions affect the spinal cord functional Magnetic Resonance Imaging (fMRI) data.
● Physiological noise correction in spinal fMRI increases the activated voxels in the spinal cord as true positive, and decreases the activated voxels in cerebrospinal fluid and surrounded tissues.
● Respiration function correction has a significant role in the reduction of physiological noise in thoracolumbar spinal cord fMRI, compared to cardiac function
effect correction.
Plain Language Summary
During the last decades, functional MRI has become a powerful tool in discovering complicated cognitive functions and diagnosing neurological problems. Recently, spinal cord fMRI is introduced to investigate sensory and motor pathways to detect functions of the central nervous system. As it has several confounding factors, including the physiological noise, spinal cord fMRI is encountered as a challenging methodology. Two of the main sources of noise in spinal cord fMRI, which affect the activation map, are respiration and heartbeat. In this study, we assessed the effects of each of these noise sources, separately. We also integrated them in thoracolumbar and lumbar regions, where most of the noise effects exist. Our results suggest that correction of the heartbeat would result in a greater effect on the activated voxels in the spinal cord, comparing with respiration noise correction. Also, we have shown that integration between these two corrections may increase the precision of fMRI activation maps. It is worth mentioning that this study is the first of its kind to investigate the effect of different noises in thoracolumbar and lumbar regions.
Type of Study:
Original |
Subject:
Behavioral Neuroscience Received: 2018/06/11 | Accepted: 2019/02/19 | Published: 2020/11/1