A visualization tool for assessment of spinal cord functional magnetic resonance imaging data quality

Functional magnetic resonance imaging (fMRI) is an extensively used neuroimaging technique to non-invasively detect neural activity. Data quality is highly variable, and fMRI analysis typically consists of a number of complex processing steps. It is crucial to visually assess images throughout analysis to ensure that data quality at each step is satisfactory. For fMRI analysis of the brain, there is a simple tool to visualize four-dimensional data on a two-dimensional plot for qualitative analysis. Despite the practicality of this method, it cannot be directly applied to fMRI data of the spinal cord, and a comparable approach does not exist for spinal cord fMRI analysis. The additional challenges encountered in spinal cord imaging, including the small size of the cord and the influence of physiological noise sources, drive the importance of developing a similar visualization technique for spinal cord fMRI. Here, we introduce a highly versatile image analysis tool to visualize spinal cord fMRI data as a simple heatmap and to co-visualize relevant traces such as physiological or motion timeseries. We present multiple variations of the plot, data features that can be identified with the heatmap, and examples of the useful qualitative analyses that can be performed using this method. The spinal cord plot can be easily integrated into an fMRI analysis pipeline and can streamline visual inspection and qualitative analysis of functional imaging data.Clinical Relevance - Implementation of this data visualization method is a simple addition to spinal cord fMRI analysis that could be used to identify normal vs. abnormal signal variation in pathologies that impact the cord, such as spinal cord injury or multiple sclerosis.