Towards direct neuronal-current MRI: a novel statistical processing technique for measurements in the presence of system imperfections.
Chiara Coletti1, Sebastian Domsch1, Frans Vos1, and Sebastian Weingärtner1
1Imaging Physics, TU Delft, Delft, Netherlands
- - Direct neuro-current MRI shows high susceptibility to B0 and B1+ inhomogeneities.
- - The proposed data-processing for neuro-current MRI time series, achieves higher sensitivity and is less susceptible to system imperfections than previous approaches.
Representative activation maps for the two processing methods, NEMO and SVarM, for different levels of B0 and B1+ inhomogeneities. On the right, corresponding plots of Dice score and surviving pixels ration (mean ± std). On the top, ground truth activation map, obtained from BOLD fMRI experiments, and representative B0 and B1+ field maps.
Simulated neuro-current time series with (a) or without (b) concomitant neural activation. Time courses (mean ± std) after each step of data processing. NEMO consists of a regression and high-pass filtering step to remove low frequency confounds (d), a rectification step converting variance differences in mean shifts (e) and extraction of the peak magnitude in the frequency spectrum at the task frequency (f). SVarM uses GLM regression to remove low frequency confounds (h), then pools the data into ON and OFF groups and tests the difference in their variance with Levene’s test (i-j).