MRI Based Brain-Specific 3D-Printed Model Aligned to Stereotactic Space for Registering Histology to MRI.

Studies that seek to predict the brain microstructure based on MRI require precise alignment of processed brain histology slices to the corresponding 3D MRI data. However, achieving such alignment is a challenging problem, due to tissue distortions and the different contrasts seen in MRI and the processed tissue. Here we present a pipeline for aligning a histology volume to the MRI data of the tissue and to a stereotaxic brain atlas.

An Open Resource for Non-human Primate Imaging.

Non-human primate neuroimaging is a rapidly growing area of research that promises to transform and scale translational and cross-species comparative neuroscience. Unfortunately, the technological and methodological advances of the past two decades have outpaced the accrual of data, which is particularly challenging given the relatively few centers that have the necessary facilities and capabilities. The PRIMatE Data Exchange (PRIME-DE) addresses this challenge by aggregating independently acquired non-human primate magnetic resonance imaging (MRI) datasets and openly sharing them via the International Neuroimaging Data-sharing Initiative (INDI).

Placement accuracy of external ventricular drain when comparing freehand insertion to neuronavigation guidance in severe traumatic brain injury.

Background: External ventricular drain (EVD) placement is a frequently performed neurosurgical procedure. Inaccuracies in drain positioning and the need for multiple passes using the classic freehand insertion technique is well reported in the literature, especially in the traumatic brain injury (TBI) population. The purpose of this study was to evaluate if electromagnetic neuronavigation guidance for EVD insertion improves placement accuracy and minimizes the number of passes in severe TBI patients.

Characterization of a Raman spectroscopy probe system for intraoperative brain tissue classification.

A detailed characterization study is presented of a Raman spectroscopy system designed to maximize the volume of resected cancer tissue in glioma surgery based on in vivo molecular tissue characterization. It consists of a hand-held probe system measuring spectrally resolved inelastically scattered light interacting with tissue, designed and optimized for in vivo measurements. Factors such as linearity of the signal with integration time and laser power, and their impact on signal to noise ratio, are studied leading to optimal data acquisition parameters.

New Protocol for Skin Landmark Registration in Image-Guided Neurosurgery: Technical Note.

Background: Newer versions of the commercial Medtronic StealthStation allow the use of only 8 landmark pairs for patient-to-image registration as opposed to 9 landmarks in older systems. The choice of which landmark pair to drop in these newer systems can have an effect on the quality of the patient-to-image registration.

Objective: To investigate 4 landmark registration protocols based on 8 landmark pairs and compare the resulting registration accuracy with a 9-landmark protocol.

Pathologic substrates of focal epilepsy influence the generation of high-frequency oscillations.

Objective: Although a clear correlation has been observed between high-frequency oscillations (HFOs) and the seizure-onset zone in distinct lesions, the role of the underlying pathologic substrates in the generation of HFOs is not well established. We aimed to investigate HFO correlates of different pathologic substrates in patients with drug-resistant epilepsy, and to examine the relation of HFOs with the anatomic location of the dysplastic lesion and surrounding tissue in patients with focal cortical dysplasia (FCD).

Methods: We studied consecutive patients with drug-resistant epilepsy who underwent intracranial electroencephalography (iEEG) investigations with depth electrodes at the Montreal Neurological Institute and Hospital, between November 2004 and May 2013.

Augmented reality in neurovascular surgery: feasibility and first uses in the operating room.

Purpose: The aim of this report is to present a prototype augmented reality (AR) intra-operative brain imaging system. We present our experience of using this new neuronavigation system in neurovascular surgery and discuss the feasibility of this technology for aneurysms, arteriovenous malformations (AVMs), and arteriovenous fistulae (AVFs).

Methods: We developed an augmented reality system that uses an external camera to capture the live view of the patient on the operating room table and to merge this view with pre-operative volume-rendered vessels.

Sub-diffuse interstitial optical tomography to improve the safety of brain needle biopsies: a proof-of-concept study.

The extraction of tissue samples during brain needle biopsy can cause life-threatening hemorrhage because of significant blood vessel injury during the procedure. Vessel rupture can have significant consequences for patient health, ranging from transient neurological deficits to death. Here, we present a sub-diffuse optical tomography technique that can be integrated into neurosurgical workflow to detect the presence of blood vessels.

Intraoperative brain cancer detection with Raman spectroscopy in humans.

Cancers are often impossible to visually distinguish from normal tissue. This is critical for brain cancer where residual invasive cancer cells frequently remain after surgery, leading to disease recurrence and a negative impact on overall survival. No preoperative or intraoperative technology exists to identify all cancer cells that have invaded normal brain.

Brain reorganization after endovascular treatment in a patient with a large arteriovenous malformation: the role of diagnostic and functional neuroimaging techniques.

We describe a case of brain cortical reorganization after embolization of a large right temporal arteriovenous malformation. A comprehensive imaging protocol, including functional magnetic resonance imaging (fMRI), cortical thickness analysis and 320-row computed tomography (CT) perfusion was used to provide information on brain plasticity and potential steal phenomenon. A 25-year-old man known for a right temporal grade V Spetzler-Martin classification arteriovenous malformation (AVM) presented with left progressive hemiparesis.

Age of language learning shapes brain structure: a cortical thickness study of bilingual and monolingual individuals.

We examined the effects of learning a second language (L2) on brain structure. Cortical thickness was measured in the MRI datasets of 22 monolinguals and 66 bilinguals. Some bilingual subjects had learned both languages simultaneously (0-3 years) while some had learned their L2 after achieving proficiency in their first language during either early (4-7 years) or late childhood (8-13 years).

Pedicle violation and Navigational errors in pedicle screw insertion using the intraoperative O-arm: A preliminary report.

Background: Use of computer-assisted insertion of pedicle screws has some advantages owing to the reportedly decreased incidence of pedicle breach and clinical events. Registration-based methods based on preoperative computed tomography imaging, 2D fluoroscopy, and 3D fluoroscopy are the most popular, however each has its limitations. O-arm-based navigation, which uses intraoperative acquisition and registration of navigated images, may overcome many of these disadvantages.

Comparison between manual and semiautomated volumetric measurements of pituitary adenomas.

Linear measurements have many limitations. The aim of this study is to compare manual and semiautomated volumetric measurements of pituitary adenomas. Magnetic resonance imaging (MRI) scans of 38 patients with pituitary adenomas were analyzed.

Automatic trajectory planning of DBS neurosurgery from multi-modal MRI datasets.

We propose an automated method for preoperative trajectory planning of deep brain stimulation image-guided neurosurgery. Our framework integrates multi-modal MRI analysis (T1w, SWI, TOF-MRA) to determine an optimal trajectory to DBS targets (subthalamic nuclei and globus pallidus interna) while avoiding critical brain structures for prevention of hemorrhages, loss of function and other complications. Results show that our method is well suited to aggregate many surgical constraints and allows the analysis of thousands of trajectories in less than 1/10th of the time for manual planning.

Tractography of the amygdala and hippocampus: anatomical study and application to selective amygdalohippocampectomy.

Object: The aim of this study was to evaluate, using diffusion tensor tractography, the white matter fibers crossing the hippocampus and the amygdala, and to perform a volumetric analysis and an anatomical study of the connections of these 2 structures. As a second step, the authors studied the white matter tracts crossing a virtual volume of resection corresponding to a selective amygdalohippocampectomy.

Methods: Twenty healthy right-handed individuals underwent 3-T MR imaging.

Atypical speech activations: PET results of 92 patients with left-hemispheric epilepsy.

Purpose: Language lateralization and factors that may influence language lateralization were investigated using positron emission tomography.

Methods: Ninety-two right-handed patients who had left-sided lesions (tumors, focal cortical dysplasia, and vascular lesions) and 19 right-handed normal subjects were included and synonym generation task was used for evaluation of language lateralization.

Results: As expected, the majority of individuals in both groups showed left hemisphere dominance.

Atypical language lateralization in patients with left hippocampal sclerosis: does the hippocampus affect language lateralization?

Aim: To provide information related to atypical language activations (right or bilateral) in positron emission tomography in patients with left clear-cut hippocampal sclerosis.

Material And Methods: Twelve right-handed patients who had been operated on left-sided hippocampal sclerosis and 12 right-handed normal subjects were included and the synonym generation task was used for evaluation of language lateralization.

Results: Atypical language activations were frequently found in the patients compared to the controls.

An indexed atlas for content-based retrieval and analysis of mammograms.

We describe the development of an indexed atlas of digital mammograms to facilitate content-based retrieval and comparative analysis of mammograms for computer-aided diagnosis (CAD) of breast cancer. Specifically, the requirements and the design of the components of the indexed archival and retrieval system are examined. In order to facilitate search by categories, the mammograms in the atlas are indexed by case number, year of acquisition, category (normal, benign disease, and malignant disease that could be screen-detected or interval cancer), and the presence of signs of disease such as masses, calcifications, bilateral asymmetry, and architectural distortion.