A quantitative spatial comparison of high-density diffuse optical tomography and fMRI cortical mapping

• Published in: NeuroImage (Orlando, Fla.) Vol. 61; no. 4; pp. 1120 - 1128
• Main Authors: Eggebrecht, Adam T., White, Brian R., Ferradal, Silvina L., Chen, Chunxiao, Zhan, Yuxuan, Snyder, Abraham Z., Dehghani, Hamid, Culver, Joseph P.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 16.07.2012; Elsevier Limited
• Subjects: Adult; Brain; Brain Mapping - methods; Brain research; Cortex; Functional neuroimaging; Human; Humans; Magnetic Resonance Imaging - methods; Mapping; Medical imaging; Methods; Neurosciences; Optical tomography; Software; Studies; Tomography; Tomography, Optical - methods; Young Adult; Human; Cortex; HD-DOT; HbR; Functional neuroimaging; Mapping; HbT; FOV; Optical tomography; DOI; HbO2
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2012.01.124

Functional neuroimaging commands a dominant role in current neuroscience research. However its use in bedside clinical and certain neuro-scientific studies has been limited because the current tools lack the combination of being non-invasive, non-ionizing and portable while maintaining moderate resolution and localization accuracy. Optical neuroimaging satisfies many of these requirements, but, until recent advances in high-density diffuse optical tomography (HD-DOT), has been hampered by limited resolution. While early results of HD-DOT have been promising, a quantitative voxel-wise comparison and validation of HD-DOT against the gold standard of functional magnetic resonance imaging (fMRI) has been lacking. Herein, we provide such an analysis within the visual cortex using matched visual stimulation protocols in a single group of subjects (n=5) during separate HD-DOT and fMRI scanning sessions. To attain the needed voxel-to-voxel co-registration between HD-DOT and fMRI image spaces, we implemented subject-specific head modeling that incorporated MRI anatomy, detailed segmentation, and alignment of source and detector positions. Comparisons of the visual responses found an average localization error between HD-DOT and fMRI of 4.4+/−1mm, significantly less than the average distance between cortical gyri. This specificity demonstrates that HD-DOT has sufficient image quality to be useful as a surrogate for fMRI. [Display omitted] ► Image-quality of high-density diffuse optical tomography is evaluated against fMRI. ► Functional maps of the visual cortex are used as a benchmark. ► We co-register subject-specific light models for DOT to MRI space. ► Center-of-mass and phase measures are used as quantitative metrics. ► The average localization error of HD-DOT is less than a typical gyral ridge size.