Juan Jose Sanchez MD, PhD, Abstract Co-Author: Nothing to Disclose

Daniel Rodriguez Bejarano, Presenter: Nothing to Disclose

Lucia Aja MD, Abstract Co-Author: Nothing to Disclose

Paloma Mora MD, Abstract Co-Author: Nothing to Disclose

Carlos Aguilera, Abstract Co-Author: Nothing to Disclose

Paloma Puyaito MD, Abstract Co-Author: Nothing to Disclose

Carlos Majos MD, PhD, Abstract Co-Author: Nothing to Disclose

To study the accuracy of DTI in the presurgical identification of the motor tract and its correlation with evoked potentials obtained during brain tumor surgery.

54 patients with brain histologcally confirmed gliomas (17 diffuse anaplastic gliomas, 8 oligoastrocytomas and 29 multiform glioblastoma) adjacent to the corticospinal tract were prospectively studied. In the 54 patients the motor tract was identified by presurgical MR (DTI sequences and tractography) and MR studies within 72 hours after surgery. During surgery, central sulcus was identified and confirmed by evoked potentials. Direct cortical monopolar high frequency phase (250Hz) stimulations were performed. For cortical stimulation an 8 contacts electrode was used whereas a current waveform with eight electromyograms was used for evoked potentials continuous monitoring. When resection approaches the pyramidal tract, subcortical stimulators were used and the electromyographic response was observed after subcortical stimulation.  

The distance between the resection cavity and the motor tract in tractographic sequences postoperatively were 2.5 to 23.7 mm. The results were correlated with data obtained from cortical evoked potentials monitored during surgery. There was a significant linear correlation of 1.08 by applying a regression test between distance and stimulus intensity (R2 = 0.8202, P <0.001).The distance between the resection cavity and the motor tract in tractographic sequences postoperatively were 2.5 to 23.7 mm. The results were correlated with data obtained from cortical evoked potentials monitored during surgery. There was a significant linear correlation of 1.08 by applying a regression test between distance and stimulus intensity (R2 = 0.8202, P <0.001).

Correlation was demonstrated between evoked potential and tractography in the analysis of the pyramidal tract by imaging based on the use of direct subcortical stimulation. DTI should be systematically included in the imaging protocol for the study of brain tumours both for etiologic diagnosis and  treatment planning in order to identify and preserve the maximum motor tract when  possible.  

The identification by DTI of the corticospinal tract prior to brain glioma surgery and its correlation with intrasurgical evoked potentials allows the neurosurgeon an accurate planning of the maximum tumour removal with motor tract preservation.

Sanchez, J, Rodriguez Bejarano, D, Aja, L, Mora, P, Aguilera, C, Puyaito, P, Majos, C, Relationship between Presurgical DTI Motor Tract Representation and Intraoperative Evoked Potentials.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14013300.html