Stereoelectroencephalography electrode placement: Detection of blood vessel conflicts

Abstract

Objective Various forms of vascular imaging are performed to identify vessels that should be avoided during stereoelectroencephalography (SEEG) planning. Digital subtraction angiography (DSA) is the gold standard for intracranial vascular imaging. DSA is an invasive investigation, and a balance is necessary to identify all clinically relevant vessels and not to visualize irrelevant vessels that may unnecessarily restrict electrode placement. We sought to estimate the size of vessels that are clinically significant for SEEG planning. Methods Thirty‐three consecutive patients who underwent 354 SEEG electrode implantations planned with computer‐assisted planning and DSA segmentation between 2016 and 2018 were identified from a prospectively maintained database. Intracranial positions of electrodes were segmented from postimplantation computed tomography scans. Each electrode was manually reviewed using “probe‐eye view” with the raw preoperative DSA images for vascular conflicts. The diameter of vessels and the location of conflicts were noted. Vessel conflicts identified on raw DSA images were cross‐referenced against other modalities to determine whether the conflict could have been detected. Results One hundred sixty‐six vessel conflicts were identified between electrodes and DSA‐identified vessels, with 0‐3 conflicts per electrode and a median of four conflicts per patient. The median diameter of conflicting vessels was 1.3 mm (interquartile range [IQR] = 1.0‐1.5 mm). The median depth of conflict was 31.0 mm (IQR = 14.3‐45.0 mm) from the cortical surface. The addition of sulcal models to DSA, magnetic resonance venography (MRV), and T1 + gadolinium images, as an exclusion zone during computer‐assisted planning, would have prevented the majority of vessel conflicts. We were unable to determine whether vessels were displaced or transected by the electrodes. Significance Vascular segmentation from DSA images was significantly more sensitive than T1 + gadolinium or MRV images. Electrode conflicts with vessels 1‐1.5 mm in size did not result in a radiologically detectable or clinically significant hemorrhage and could potentially be excluded from consideration during SEEG planning.

Indications, Techniques, and Outcomes of Robot-Assisted Insular Stereo-Electro-Encephalography: A Review

“…In studies made on susceptibility weighted imaging (SWI) or digital subtraction angiography (DSA), it appears that trajectories at the vicinity of vessels of a caliber < 1.5 mm in the brain parenchyma (not at the cortical entry) could not be hazardous (65). Other authors suggest that SWI may overestimate the vasculature and thus limit the number of trajectories without influencing the bleeding incidence (66).…”

Automation Advances in Stereoelectroencephalography Planning

“…Once segmented, 3-D representations of the vascular trees can be generated and considered as structures during automated trajectory planning. 9 This highlights the important difference between vessels that can be seen by the naked eye on the source imaging by the surgeon, compared with those that can be considered and avoided by the automated planning software.…”

“…DSA allows vessels less than 1 mm in diameter to be reliably segmented, whereas MR-based modalities are reported to be between 2 mm and 4 mm in diameter. 15 Some studies have shown electrode-vessel conflicts with median vessel diameters less than 1.5 mm do not result in any radiological hemorrhage, 9 , 16 suggesting that they may be clinically insignificant. The implication of considering clinically nonsignificant vasculature is that this may over-restrict SEEG electrode trajectory planning and unnecessarily limit the intracranial sampling.…”

How technology is driving the landscape of epilepsy surgery

“…The reported complication rates after SDE implantations ranged from 5% to 17% per procedure, whereas the complication rate per SEEG procedure was less than 1% 6,7 . Second, the introduction of new radiological and computational innovations and a wide range of navigational image‐guided applications, in addition to new stereotactic methods, allowed for a more convenient and faster depth electrode insertion 5‐6,8,9 . Numerous targets can now be reached in a simplified, more efficient and accurate fashion.…”

“…To minimize radiation exposure, especially in the pediatric group, 3T MRI proved to be adequate for most stereotactic procedures 16 . In addition, novel three‐dimensional (3D) computerized models can now further increase the accuracy and safety by automated vessel detection 8 …”