Using fMRI to guide neurosurgery in a combined 1.5 Tesla MR-operating room

To take advantage of MR-guided surgical procedures performed in a combined MR-OR, we have implemented and validated a practical fMRI scheme for localizing primary motor area and assessing its proximity to a lesion volume. The fMRI scheme consists of a dynamical blood oxygenation level dependent (BOLD) imaging technique and a motor task paradigm. The functional imaging was based on gradient-echo(GE) echo planar imaging (EPI) (TR/TE=3000/50m sec). The task paradigm involves a periodic finger movement in which subject was instructed to tap his/her thumb on the other four fingers sequentially as well as to alternate between the right and left sides. During the task, a dynamical fMRI was performed concurrently covering the volume of interest. By using the fMRI scheme, we have successfully performed ten fMRI examinations immediately prior to surgery in the combined MR-OR on the same surgical table top to localize the eloquent functional area of interests. Also we have developed methods of detrending and presenting fMRI results to neurosurgeons in an intuitive 3-dimensional surface-rendered display format that closely matches the patienthead position underintervention. Representative cases showed that fMRI results helped neurosurgeons making the optimal surgical decisions prior to craniotomy.