James L. Leach MD, Presenter: Nothing to Disclose

Chris McPherson MD, Abstract Co-Author: Nothing to Disclose

Achala Sameer Vagal MD, Abstract Co-Author: Nothing to Disclose

Janice Carrozzella, Abstract Co-Author: Nothing to Disclose

Phil Theodosopoulos MD, Abstract Co-Author: Nothing to Disclose

Ron Warnick MD, Abstract Co-Author: Nothing to Disclose

John Tew, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

Functional MRI (fMRI) and diffusion tensor imaging tractography (DTI) can assist in surgical planning and resection in patients with brain tumors. There have been few studies evaluating combined DTI and fMRI data for intraoperative use with neuronavigation, particularly at 3T. We chose to assess the validity of fMRI and DTI identified eloquent cortical and subcortical regions by correlating these areas to resection margin location and new postoperative neurologic deficit.

Sixteen patients with neoplasms involving eloquent cortical and subcortical regions underwent both fMRI and DTI at 3T. fMRI assessed speech, motor, and visual regions. Processing utilized the GLM, with a threshold of at least p <0.01. Tractography utilized 25 direction DTI with seed and end points defined by fMRI and anatomic landmarks, a FA threshold of 0.16-0.2, and outlined the arcuate fasciculus, corticospinal, and geniculocalcarine tracts. Initial postoperative MR imaging was fused with the operative planning images using an automated rigid registration technique, corrected for brain shift. Resection margin was manually outlined and distance between the resection margin and DTI and fMRI objects documented. Clinical outcome data was collected in a blinded fashion utilizing the longest follow-up available, focusing on new post-operative deficits.

39 DTI and fMRI defined objects were at risk by the planned surgical approach and resection. At longest clinical follow-up (mean 5 months), 12 (75%) had no or minimal new deficit and 4 (25%) had moderate new deficit. When margins of fMRI and DTI objects were respected, no deficits occurred. Violation of the margin of at risk fMRI and DTI objects (20 objects) by the resection had a sensitivity of 100%, specificity of 61.3%, PPV of 40%, and NPV of 100% for new clinical deficit.

Combined fMRI and tractography is a useful adjunct during brain tumor resection in and near eloquent regions. By using these techniques and respecting the boundaries of fMRI/DTI objects no deficits occurred. Resections violating the margins of created fMRI and DTI objects had a predictable tendency for new significant clinical deficit. Further evaluation of these promising techniques is warranted.

Combined fMRI and DTI at 3T with operative integration is a useful adjunct to brain tumor resection, can help guide resection extent and approach, and correlates with post-operative deficit.

Leach, J, McPherson, C, Vagal, A, Carrozzella, J, Theodosopoulos, P, Warnick, R, Tew, J, et al, , Operative Integration of Functional MRI and Tractography at 3 T: Correlation of Resection Extent with Post-operative Clinical Outcome in Patients with Brain Neoplasia.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6009775.html