title: Preoperative mapping of the sensorimotor cortex: comparative assessment of task-based and resting-state FMRI.
abstract: Resting state fMRI (rs-fMRI) has recently been considered as a possible complement or alternative to task-based fMRI (tb-fMRI) for presurgical mapping. However, evidence of its usefulness remains scant, because existing studies have investigated relatively small samples and focused primarily on qualitative evaluation. The aim of this study is to investigate the clinical usefulness of rs-fMRI in the context of presurgical mapping of motor functions, and in particular to determine the degree of correspondence with tb-fMRI which, while not a gold-standard, is commonly used in preoperative setting. A group of 13 patients with lesions close to the sensorimotor cortex underwent rs-fMRI and tb-fMRI to localize the hand, foot and mouth motor areas. We assessed quantitatively the degree of correspondence between multiple rs-fMRI analyses (independent-component and seed-based analyses) and tb-fMRI, with reference to sensitivity and specificity of rs-fMRI with respect to tb-fMRI, and centre-of-mass distances. Agreement with electro-cortical stimulation (ECS) was also investigated, and a traditional map thresholding approach based on agreement between two experienced operators was compared to an automatic threshold determination method. Rs-fMRI can localize the sensorimotor cortex successfully, providing anatomical specificity for hand, foot and mouth motor subregions, in particular with seed-based analyses. Agreement with tb-fMRI was only partial and rs-fMRI tended to provide larger patterns of correlated activity. With respect to the ECS data available, rs-fMRI and tb-fMRI performed comparably, even though the shortest distance to stimulation points was observed for the latter. Notably, the results of both were on the whole robust to thresholding procedure. Localization performed by rs-fMRI is not equivalent to tb-fMRI, hence rs-fMRI cannot be considered as an outright replacement for tb-fMRI. Nevertheless, since there is significant agreement between the two techniques, rs-fMRI can be considered with caution as a potential alternative to tb-fMRI when patients are unable to perform the task.
authors.affiliation: Neuroradiology Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milano, Italy; Scientific Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milano, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Rosazza
authors.affiliation: Neuroradiology Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milano, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Aquino
authors.affiliation: Neuroradiology Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milano, Italy.
authors.forename: Ludovico
authors.initials: L
authors.lastname: D'Incerti
authors.affiliation: Neurosurgery Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milano, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Cordella
authors.affiliation: Neuroradiology Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milano, Italy.
authors.forename: Adrian
authors.initials: A
authors.lastname: Andronache
authors.affiliation: Center for Mind/Brain Sciences (CIMeC), University of Trento, Trento, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Zacà
authors.affiliation: Neuroradiology Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milano, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Bruzzone
authors.affiliation: Neurosurgery Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milano, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Tringali
authors.affiliation: Scientific Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milano, Italy; Center for Mind/Brain Sciences (CIMeC), University of Trento, Trento, Italy.
authors.forename: Ludovico
authors.initials: L
authors.lastname: Minati
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001931:Brain Mapping; D004558:Electric Stimulation; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D057234:Preoperative Period; D011597:Psychomotor Performance; D012146:Rest; D066191:Sensorimotor Cortex / Q000502:physiology* / Q000503:physiopathology; D059629:Signal-To-Noise Ratio