Pre-Surgical fMRI Mapping of Language: Accuracy of Mapping Language Regions in Patients with Mass Lesions

OBJECTIVES: (1) To introduce a novel methodology for co-registration of pre- and post-surgical clinical imaging. (2) To document prognostic imaging correlates of functional imaging/tractography to post-surgical outcome. BACKGROUND: The accuracy, reproducibility, and clinical applicability of pre-surgical imaging evaluation of language in patients with mass lesions near language areas has been previously demonstrated by this group. The accuracy and clinical applicability of pre-surgical mapping can be confirmed by correlating pre-surgical imaging to post-surgical imaging and then to any related language deficits. It is hypothesized that if the surgical resection cavity includes areas of language activation language deficits will result. Correlation of outcomes with language mapping and post-surgical imaging has not been documented in the literature. MATERIALS AND METHODS: Pre-surgical functional maps and diffusion tensor tracts were created utilizing AFNI and DynaSuite software following fMRI/DTI tractography protocol to evaluate language regions. Post-surgical follow-up of speech deficits was obtained from the medical charts. A computerized method was used to co-register pre- and post-surgical images. Multiple variables including structural, functional, and clinical findings were documented and analyzed for correlation to outcome. RESULTS: 13 patients with left-sided mass lesions with complete pre- and post-surgical clinical imaging and clinical evaluation were included in this retrospective study. Of the 13 patients only 1 patient was noted to have a severe post-operative language deficit and 4 patients were noted to have moderate post-operative laguage deficits. Accurate co-registration was achieved in all cases. Prognostic indicators of language deficits included proximity of activation to the resection cavity, the level of resection, and involvement of the adjacent trajectory of arcuate fasciculus. CONCLUSIONS: (1) Pre-surgical fMRI was accurately co-registered with post-surgical images. (2) Structural, functional, and DTI images were shown to have prognostic value for post-surgical language deficits.