On the use of digital subtraction angiography in SEEG surgical planning to prevent collisions with vessels.

Abstract OBJECTIVE Stereoelectroencephalography (SEEG) consists in the implantation of microelectrodes for the electrophysiological characterization of epileptogenic networks. To reduce a possible risk of intracranial bleeding by vessel rupture during the electrode implantation, the stereotactic trajectories must follow avascular corridors. The use of digital subtraction angiography (DSA) for vascular visualization during planning is controversial due to the additional risk related to this procedure. Here we evaluate the utility of this technique for planning when the neurosurgeon has it available together with gadolinium-enhanced T1-weight magnetic resonance sequence (T1-Gd) and computer tomography angiography (CTA). METHODS Twenty-two implantation plans for SEEG were initially done using T1-Gd imaging (251 trajectories). DSA was only used later during the revision process. In six patients CTA was available at this point as well. We quantified the position of the closest vessel to the trajectory in each of the imaging modalities. RESULTS Two thirds of the trajectories that appeared vessel-free in the T1-Gd or CTA presented vessels in their proximity, as shown by DSA. Those modifications only required small shifts of both the entry and target point so the diagnostic aims were preserved. CONCLUSIONS T1-Gd and CTA, despite being the most commonly used techniques for SEEG planning, frequently fails to reveal vessels that are dangerously close to the trajectories. Higher resolution vascular imaging techniques, such DSA, can provide the neurosurgeon with crucial information about vascular anatomy, resulting in safer plans.