The influence of varying the number of characters per row on the accuracy and reproducibility of the ETDRS visual acuity chart

Background As part of an effort to improve upon the Snellen chart, we provide a standardized version of the ETDRS chart utilizing five characters in each row. The choice of five characters contradicts the recommended ten characters per row determined by the NAS-NRC, a…

Snellen and ETDRS Charts Compared Using a Computer Simulation

Abstract Aim: To compare accuracy, reproducibility and test duration for the Snellen and the Early Treatment of Diabetic Retinopathy Study (ETDRS) charts, two main tools used to measure visual acuity (VA). Methods: A computer simulation was programmed to run multiple…

The role of automatic computer-aided surgical trajectory planning in improving the expected safety of stereotactic neurosurgery

Abstract Purpose Minimal invasion computer-assisted neurosurgical procedures with various tool insertions into the brain may carry hemorrhagic risks and neurological deficits. The goal of this study is to investigate the role of computer-based surgical trajectory planning tools in improving the…

Deep brain stimulation surgery time reduction based on the automatic detection of the subthalamic nucleus: method and preliminary results

Abstract. Deep brain stimulation (DBS) surgery of the subthalamic nucleus (STN) is an effective therapy in the management of the motor symptoms of advanced Parkinson’s disease (PD). The accurate localization of the STN is essential to achieve an optimal outcome…

Microelectrode Recording Duration and Spatial Density Constraints for Automatic Targeting of the Subthalamic Nucleus

Abstract Background: Accurate detection of the boundaries of the subthalamic nucleus (STN) in deep brain stimulation (DBS) surgery using microelectrode recording (MER) is considered to refine localization and may therefore improve clinical outcome. However, MER tends to extend operation time…

Reduced risk trajectory planning in image-guided keyhole neurosurgery

Abstract Purpose: The authors present and evaluate a new preoperative planning method and computer software designed to reduce the risk of candidate trajectories for straight rigid tool insertion in image-guided keyhole neurosurgery. Methods: Trajectories are computed based on the surgeon-defined…

Fiducial Optimization for Minimal Target Registration Error in Image-Guided Neurosurgery

Abstract This paper presents new methods for the optimal selection of anatomical landmarks and optimal placement of fiducial markers in image-guided neurosurgery. These methods allow the surgeon to optimally plan fiducial marker locations on routine diagnostic images before preoperative imaging…

Target and Trajectory Clinical Application Accuracy in Neuronavigation

Abstract BACKGROUND: Catheter, needle, and electrode misplacement in navigated neurosurgery can result in ineffective treatment and severe complications. OBJECTIVE: To assess the Ommaya ventricular catheter localization accuracy both along the planned trajectory and at the target. METHODS: We measured the…

Geometrical analysis of registration errors in point-based rigid-body registration using invariants

Abstract Point-based rigid registration is the method of choice for aligning medical datasets in diagnostic and image-guided surgery systems. The most clinically relevant localization error measure is the Target Registration Error (TRE), which is the distance between the image-defined target…

Trajectory Planning with Augmented Reality for Improved Risk Assesment in Image-guided Keyhole Neurosurgery

Abstract We present a new preoperative planning method for reducing the risk associated with the insertion of straight tools in image-guided keyhole neurosurgery. The method quantifies the risks of multiple candidate trajectories and presents them on a physical model of…

Improving accuracy and safety in image-guided keyhole neurosurgery

Abstract Image-guided keyhole neurosurgery consists of targeting a straight surgical tool, such as a needle or a catheter, with a support guidance system towards a target location inside the brain. The target and trajectory are defined on a preoperative MRI/CT…

Trajectory planning method for reduced patient risk in image-guided neurosurgery: concept and preliminary results

Abstract We present a new preoperative planning method to quantify and help reduce the risk associated with needle and tool insertion trajectories in image-guided keyhole neurosurgery. The goal is to quantify the risk of a proposed straight trajectory, and/or to…

A method for planning safe trajectories in image-guided keyhole neurosurgery

Abstract We present a new preoperative planning method for reducing the risk associated with insertion of straight tools in image-guided keyhole neurosurgery. The method quantifies the risks of multiple candidate trajectories and presents them on the outer head surface to…

Surface-based facial scan registration in neuronavigation procedures: a clinical study

Abstract Object. Surface-based registration (SBR) with facial surface scans has been proposed as an alternative for the commonly used fiducial-based registration in image-guided neurosurgery. Recent studies comparing the accuracy of SBR and fiducial-based registration have been based on a few…

Localization and registration accuracy in image guided neurosurgery: a clinical study

Abstract Purpose To measure and compare the clinical localization and registration errors in image-guided neurosurgery, with the purpose of revising current assumptions. Materials and methods Twelve patients who underwent brain surgeries with a navigation system were randomly selected. A neurosurgeon…

Advanced Planning and Intra-operative Validation for Robot-Assisted Keyhole Neurosurgery In ROBOCAST

Abstract ROBOCAST is a multi-national project comprising several institutes which aim at outlining and implementing a prototype system for advanced, robot-assisted keyhole neurosurgery. This paper reports mainly on software and sensor aspects of the system in the pre- and intra-operative…

Worst-case analysis of target localization errors in fiducial-based rigid body registration

Abstract Fiducial-based rigid registration is the preferred method for aligning the preoperative image with the intra-operative physical anatomy in existing image-guided surgery systems. After registration, the targets locations usually cannot be measured directly, so the Target Registration Error (TRE) is…

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