Subthalamic Nucleus Visualization on Routine Clinical Preoperative MRI Scans: A Retrospective Study of Clinical and Image Characteristics Predicting Its Visualization

Abstract

Background: The visualization of the subthalamic nucleus (STN) on magnetic resonance imaging (MRI) is variable. Studies of the contribution of patient-related factors and intrinsic brain volumetrics to STN visualization have not been reported previously. Objective: To assess the visualization of the STN during deep brain stimulation (DBS) surgery in a clinical setting. Methods: Eighty-two patients undergoing pre-operative MRI to plan for STN DBS for Parkinson disease were retrospectively studied. The visualization of the STN and its borders was assessed and scored by 3 independent observers using a 4-point ordinal scale (from 0 = not seen to 3 = excellent visualization). This measure was then correlated with the patients’ clinical information and brain volumes. Results: The mean STN visualization scores were 1.68 and 1.63 for the right and left STN, respectively, with a good interobserver reliability (intraclass correlation coefficient: 0.744). Older age and decreased white matter volume were negatively correlated with STN visualization (p < 0.05). Conclusion: STN visualization is only fair to good on routine MRI with good concordance of interindividual rating. Advancing age and decreased white matter are associated with poor visualization of the STN. Knowledge about factors contributing to poor visualization of the STN could alert a surgeon to modify the imaging strategy to optimize surgical targeting.

Online Mapping With the Deep Brain Stimulation Lead: A Novel Targeting Tool in Parkinson's Disease

“…However, neither high-resolution 39 nor conventional 40 imaging can account for perioperative deviations from preoperative anatomical targeting such as brain-shift, 41 which often contribute to suboptimal DBS lead placements. 42 Such deviations can only be accounted for when electrophysiological mapping procedures are correctly employed.…”

A comparison of indirect and direct targeted STN DBS in the treatment of Parkinson’s disease—surgical method and clinical outcome over 15-year timespan

“…The lead's location accuracy in STN was verified by microelectrode registration (MER) with multiple microelectrodes to enable measuring the electrical activity on a single-neuron level [3,20]. As imaging technology developed, it became possible to measure MCP from CT or MRI scans [16] and later further development of MRI imaging [4,9,15] enabled the possibility of defining patientspecific anatomy of the STN [19] and target direct DBS electrodes. Alongside the development of imaging has enabled precise postoperative analysis of the lead location [5,7,11], thus facilitating the optimal programming.…”

Neuroimaging Technological Advancements for Targeting in Functional Neurosurgery

“…The therapeutic effects achieved with DBS hinge upon selective stimulation of the intended structure through accurate and precise placement of the electrodesmaximizing therapeutic benefits while minimizing spillover onto neighboring structures that may produce adverse effects [5,6]. Despite significant advances in neuroimaging technology over the past decades, routinely acquired preoperative brain magnetic resonance imaging (MRI) sequences remain deficient at directly visualizing DBS targets for stereotactic planning purposes [7,8]. Some groups have developed dedicated MRI sequences that visualise some of the anatomical structures commonly targeted during DBS surgery on MRI at 1.5T field strengths such as the STN and posteroventral GPi.…”

“…UHF MRI may also hold promise for essential tremor DBS, which most commonly targets the motor thalamus [1]. Indeed, the potential benefits here may even be more pronounced than for PD; while the STN may be adequately visualised on routinely acquired MRI [7], the thalamic intranuclei, including the VIM, are not appreciated at all on current MRI protocols. These nuclei can be visualized with appropriate MRI sequences at 7T MRI [31,33], however, which is a notable advantage when planning DBS surgery for tremor.…”