fMRI and DOI Non-Rigid Registration with Discrete Curvature Flows and Mutual Information

Combined fMRI and optical imaging of intrinsic (hemodynamic) signals has been performed in earlier studied simultaneously. Simultaneous measurements showed a general spatial overlap, low TR (2 sec) and a poor spatial resolution (0.5x1 mm in=plane, slice thickness=2mm) from. Good correspondence between BOLD signal and optically measured Hb was also shown in simultaneous fMRI/DOI human studies, albeit on a low-resolution spatial scale inherent to diffuse optical methods. Multiple-wavelength (spectroscopic) optical imaging of the intrinsic signals enable simultaneous measurements of oxyhemoglobin (HbO), deoxyhemoglobin (Hb) and total hemoglobin (HbT). Quantitative estimates of the concentrations of Hb, HbO, and HbT are obtained by fitting the observed signal changes at all wavelengths to a model, taking into account the respective absorption spectra of HbO and Hb.