Three-dimensional SPACE fluid-attenuated inversion recovery at 3 T to improve subthalamic nucleus lead placement for deep brain stimulation in Parkinson's disease: from preclinical to clinical studies

Abstract

abbreviatioNs DBS = deep brain stimulation; eSTN = electrophysiologically identified subthalamic nucleus; H&Y = Hoehn and Yahr; LEDD = levodopa equivalent daily dose; M12 = month 12 after implantation; NHP = nonhuman primate; PD = Parkinson's disease; SPACE = sampling perfection with application-optimized contrasts using different flip angle evolutions; STN = subthalamic nucleus; TEED = total electrical energy delivered; T1WI = T1-weighted imaging; T2WI = T2-weighted imaging; UPDRS = Unified Parkinson's Disease Rating Scale. . However, the procedure, which requires multimodal perioperative exploration such as imaging, electrophysiology, or clinical examination during macrostimulation to secure lead positioning, remains challenging because the STN cannot be reliably visualized using the gold standard, T2-weighted imaging (T2WI) at 1.5 T. Thus, there is a need to improve imaging tools to better visualize the STN, optimize DBS lead implantation, and enlarge DBS diffusion. methods Gradient-echo sequences such as those used in T2WI suffer from higher distortions at higher magnetic fields than spin-echo sequences. First, a spin-echo 3D SPACE (sampling perfection with application-optimized contrasts using different flip angle evolutions) FLAIR sequence at 3 T was designed, validated histologically in 2 nonhuman primates, and applied to 10 patients with PD; their data were clinically compared in a double-blind manner with those of a control group of 10 other patients with PD in whom STN targeting was performed using T2WI. results Overlap between the nonhuman primate STNs segmented on 3D-histological and on 3D-SPACE-FLAIR volumes was high for the 3 most anterior quarters (mean [± SD] Dice scores 0.73 ± 0.11, 0.74 ± 0.06, and 0.60 ± 0.09). STN limits determined by the 3D-SPACE-FLAIR sequence were more consistent with electrophysiological edges than those determined by T2WI (0.9 vs 1.4 mm, respectively). The imaging contrast of the STN on the 3D-SPACE-FLAIR sequence was 4 times higher (p < 0.05). Improvement in the Unified Parkinson's Disease Rating Scale Part III score (off medication, on stimulation) 12 months after the operation was higher for patients who underwent 3D-SPACE-FLAIRguided implantation than for those in whom T2WI was used (62.2% vs 43.6%, respectively; p < 0.05). The total electrical energy delivered decreased by 36.3% with the 3D-SPACE-FLAIR sequence (p < 0.05). coNclusioNs 3D-SPACE-FLAIR sequences at 3 T improved STN lead placement under stereotactic conditions, improved the clinical outcome of patients with PD, and increased the benefit/risk ratio of STN-DBS surgery.

Diagnostic Quality of 3D T2-SPACE Compared with T2-FSE in the Evaluation of Cervical Spine MRI Anatomy

“…In contrast to studies of degenerative disease by using T2-SPACE [2][3][4][5][6][7] and the MR imaging anatomy study by Meindl et al, 8 our interobserver agreement for T2-SPACE ranged from slight to fair. It is unclear if this reflects any underlying difference in experience with this se- quence between the 2 reviewers.…”

“…The SPACE sequence is a proprietary 3D FSE sequence and is analogous to the VISTA (volume isotropic turbo spin-echo acquisition [Philips Healthcare, Best, the Netherlands]) sequence or Cube sequence (GE Healthcare, Milwaukee, Wisconsin). 1 Studies have evaluated the advantages of 3D T2WI sequences in brain 2 and head and neck imaging 3,4 ; however, there have only been a small number of studies investigating their value in spine MR imaging. [5][6][7] Most of these studies have compared the visualization of degenerative disease of the lumbar spine on conventional T2-FSE sequences versus 3D T2WI sequences.…”

Optogenetic Tractography for anatomo-functional characterization of cortico-subcortical neural circuits in non-human primates

“…The whole STN was identified bilaterally on the histological blocks for NHP 1 & 2, and for NHP3 using a MRI sequence, developed for direct visualization of the STN 33 , whereas it had never previously been possible to precisely and reliably segment the STN on NHP MRI before. The primary motor cortex was found to be the main source of motor cortex projections to the STN (49.2 +/− 5.8% of all streamlines), followed by the premotor cortex (23.6 +/− 3.3%), supplementary area (19.9 +/− 7.6%), rostral cingular cortex (7.3 +/− 1.4%), caudo-dorsal cingular cortex (2 +/− 0.7%) and caudo-ventral cingular cortex (0.4 +/− 0.1%) (Table 1 ).…”

Microsurgical anatomy of the subthalamic nucleus: correlating fiber dissection results with 3-T magnetic resonance imaging using neuronavigation

“…7 However, even with the best available imaging techniques for displaying brain anatomy in vivo, the peri-STN area is still poorly visualized. 25,30,46,49 Several approaches have been described to optimize STN targeting. DBS centers predominantly use the con-cept of a "2-stage method" for accurate and clinically effective positioning of electrodes.…”