Parikshit Juvekar

• MBBS
• PostDoc Position at Brigham and Women's Hospital

Introduction Neuronavigation greatly improves the surgeon’s ability to approach, assess and operate on brain tumors, but tends to lose its accuracy as the surgery progresses and substantial brain shift and deformation occurs. Intraoperative MRI (iMRI) can partially address this problem but is resource intensive and workflow disruptive. Intraoperati...

Simple Summary Achieving gross total resection during the first surgical intervention is particularly important for chondrosarcomas and chordomas, as recurrences are frequently impossible to resect due to post-surgical and post-radiation scarring and vascular fragility. Despite overall survival and progression-free survival being strongly dictated...

Numerous traditional linguistic theories propose that semantic language pathways convert sounds to meaningful concepts, generating interpretations ranging from simple object descriptions to communicating complex, analytical thinking. Although the dual-stream model of Hickok and Poeppel is widely employed, proposing a dorsal stream, mapping speech s...

Surgical resection continues to be the primary initial therapeutic strategy in the treatment of patients with brain tumors. Computerized cranial neuronavigation based on preoperative imaging offers precision guidance during craniotomy and early tumor resection but progressively loses validity with brain shift. Intraoperative MRI (iMRI) and intraope...

The standard of care for brain tumors is maximal safe surgical resection. Neuronavigation augments the surgeon’s ability to achieve this but loses validity as surgery progresses due to brain shift. Moreover, gliomas are often indistinguishable from surrounding healthy brain tissue. Intraoperative magnetic resonance imaging (iMRI) and ultrasound (iU...

BACKGROUND AND OBJECTIVES Low-quality data on image-guided external ventricular drain (EVD) accuracy are in large part due to a lack of widespread usage of this system for EVD placement. The potential disconnect between user preferences and existing technologies should be explored to guide future developments. The goal of this study was to survey n...

INTRODUCTION Automated delineation of gliomas in intraoperative ultrasound (iUS) could provide timely information to surgeons. While artificial intelligence (AI) frameworks have shown promising results for delineating gliomas in preoperative MRI, automated delineation in iUS remains a challenging and open problem. METHODS A deep learning algorithm...

The aim of the study was to map the disruption of functional connectome in patients with gliomas using resting-state functional MRI (rs-fMRI) acquired before surgery (3T scanner). 54 patients with gliomas were included (M = 34, mean age = 50.8 y). Manual segmentation of lesions was performed on T1w and T2w MRI scans. Whole-brain measures of network...

We present a novel method for intraoperative patient-to-image registration by learning Expected Appearances. Our method uses preoperative imaging to synthesize patient-specific expected views through a surgical microscope for a predicted range of transformations. Our method estimates the camera pose by minimizing the dissimilarity between the intra...

We introduce MHVAE, a deep hierarchical variational auto-encoder (VAE) that synthesizes missing images from various modalities. Extending multi-modal VAEs with a hierarchical latent structure, we introduce a probabilistic formulation for fusing multi-modal images in a common latent representation while having the flexibility to handle incomplete im...

The standard of care for brain tumors is maximal safe surgical resection as the first step. Neuronavigation augments the surgeon's ability to achieve this but loses validity due to brain shift as surgery progresses. Moreover, many gliomas are difficult to distinguish from adjacent healthy brain tissue. Intraoperative MRI (iMRI) is a useful surgical...

Background: Diffusion magnetic resonance imaging white matter tractography, an increasingly popular preoperative planning modality used for pre-surgical planning in brain tumor patients, is employed with the goal of maximizing tumor resection while sparing postoperative neurological function. Clinical translation of white matter tractography has b...

This work presents a novel tool-free neuronavigation method that can be used with a single RGB commodity camera. Compared with freehand craniotomy placement methods, the proposed system is more intuitive and less error prone. The proposed method also has several advantages over standard neuronavigation platforms. First, it has a much lower cost, si...

Background Presence of residual neurovascular activity within glioma lesions have been recently demonstrated via functional MRI (fMRI) along with active electrical synapses between glioma cells and healthy neurons that influence survival. In this study, we aimed to investigate whether gliomas demonstrate synchronized neurovascular activity with the...

Accurate brain meningioma segmentation and volumetric assessment are critical for serial patient follow-up, surgical planning and monitoring response to treatment. Current gold standard of manual labeling is a time-consuming process, subject to inter-user variability. Fully-automated algorithms for meningioma segmentation have the potential to brin...

Purpose: NousNav is a complete low-cost neuronavigation system that aims to democratize access to higher-quality healthcare in lower-resource settings. NousNav's goal is to provide a model for local actors to be able to reproduce, build and operate a fully functional neuronavigation system at an affordable cost. Methods: NousNav is entirely open...

Introduction Patients with recurrent brain metastases who have exhausted external radiation options pose a treatment challenge in the setting of advances in systemic disease control which have improved quality of life and survival. Brachytherapy holds promise as salvage therapy given its ability to enforce surgical cytoreduction and minimize region...

INTRODUCTION Maximal safe extent of resection extends survival for gliomas. Surgical adjuncts including neuronavigation, intraoperative MRI (iMRI), intraoperative ultrasonography (iUS), and fluorescence imaging can help surgeons minimize unintentional residual tumor; each with associated limitations including cost, availability, susceptibility to b...

Purpose The safety and effectiveness of laser interstitial thermal therapy (LITT) relies critically on the ability to continuously monitor the ablation based on real-time temperature mapping using magnetic resonance thermometry (MRT). This technique uses gradient recalled echo (GRE) sequences that are especially sensitive to susceptibility effects...

We propose in this paper an efficient method to segment cortical vessels in craniotomy images acquired by the surgical microscope. Our method uses a vesselness-enforced convolutional neural network to classify each pixel of a craniotomy image as a vessel or surrounding tissue. This permits training the network not only on appearance-based features...

Digital Subtraction Angiography (DSA) provides high resolution image sequences of blood flow through arteries and veins and is considered the gold standard for visualizing cerebrovascular anatomy for neurovascular interventions. However, acquisition frame rates are typically limited to 1–3 fps to reduce radiation exposure, and thus DSA sequences of...

Objective: A craniotomy is the removal of a part of the skull to allow surgeons to have access to the brain and treat tumors. When accessing the brain, a tissue deformation occurs and can negatively influence the surgical procedure outcome. In this work, we present a novel Augmented Reality neurosurgical system to superimpose pre-operative 3D mesh...

Accurate brain meningioma detection, segmentation and volumetric assessment are critical for serial patient follow-up, surgical planning and monitoring response to treatment. Current gold standard of manual labeling is a time-consuming process, subject to inter-user variability. Fully-automated algorithms for meningioma detection and segmentation h...

Identification and labelling of white matter tracts is a crucial but time-consuming step in neurosurgical planning requiring user expertise. This is pronounced in regions of edema where fiber-tracking tools, utilizing single-tensor DTI (Diffusion Tensor Imaging), on commercial neuronavigation platforms hinder clinical decision-making with inadequat...

INTRODUCTION: Previous literature reports freehand EVD misplacement occurs up to 41% of the time, requires 2 or more passes, with 39% of patients requiring multiple passes (mean of 4.1). Image-guidance (IG) offers near-perfect catheter placement but is often unamenable for bedside use for a multitude of reasons such as limited portability, extensiv...

Neuroimaging offers a non-invasive means to probe tumor tissue in order to inform decision making at all phases of brain tumor treatment. Diffusion MRI is particularly sensitive to tumor tissue microstructure, with greater heterogeneity being reflected as a larger diffusional kurtosis. Q-Space Trajectory Imaging (QTI) uses tensor-valued diffusion e...

During a craniotomy, the skull is opened to allow surgeons to have access to the brain and perform the procedure. The position and size of this opening are chosen in a way to avoid critical structures, such as vessels, and facilitate the access to tumours. Planning the operation is done based on pre-operative images and does not account for intra-o...

Intra-operative brain shift is a well-known phenomenon that describes non-rigid deformation of brain tissues due to gravity and loss of cerebrospinal fluid among other phenomena. This has a negative influence on surgical outcome that is often based on pre-operative planning where the brain shift is not considered. We present a novel brain-shift awa...

Abstract #4779: Diffusion MRI is sensitive to the configuration of cell structures on the microscopic level, and may be a biomarker of tumor grade. High-grade gliomas are hypothesized to be more heterogeneous on a microscopic scale, when compared to low-grade; a feature that should be reflected in the diffusional kurtosis. To explore this premise,...

Synopsis We present an open-source software suite, SlicerDMRI (dmri.slicer.org), that enables neurosurgical planning research using diffusion magnetic resonance imaging (dMRI). SlicerDMRI is built upon and deeply integrated with 3D Slicer, an NIH-supported open-source platform for medical image informatics, image processing, and three-dimensional v...

With the increasing availability of new image registration approaches, an unbiased evaluation is becoming more needed so that clinicians can choose the most suitable approaches for their applications. Current evaluations typically use landmarks in manually annotated datasets. As a result, the quality of annotations is crucial for unbiased compariso...

Brain shift is a non-rigid deformation of brain tissue that is affected by loss of cerebrospinal fluid, tissue manipulation and gravity among other phenomena. This deformation can negatively influence the outcome of a surgical procedure since surgical planning based on pre-operative image becomes less valid. We present a novel method to compensate...

PURPOSE We present SlicerDMRI, an open-source software suite that enables research using diffusion magnetic resonance imaging (dMRI), the only modality that can map the white matter connections of the living human brain. SlicerDMRI enables analysis and visualization of dMRI data and is aimed at the needs of clinical research users. SlicerDMRI is bu...

Differences between males and females in brain development and in the organization and hemispheric lateralization of brain functions have been described, including in language. Sex differences in language organization may have important implications for language mapping performed to assess, and minimize neurosurgical risk to, language function. Thi...

Purpose To evaluate surgical resection with brachytherapy placement as a salvage treatment in patients with recurrent high-grade meningioma who exhausted prior external beam treatment options. Methods Single-center retrospective review of our institutional experience of brachytherapy implantation from 2012 to 2018. The primary outcome of the study...

Differences between males and females in brain development, organization, and hemispheric lateralization have been described, including for language function. However, the implications of sex differences in language organization for presurgical language mapping are unknown. We carried out a retrospective analysis in 47 patients with MBT (22 females...

Background/Objective: Pituitary adenomas, particularly functional adenomas, can cause drastic hormone fluctuations throughout the body. However, it is not known how endogenous hormone disorders shape the patient’s brain. This study used resting-state functional magnetic resonance imaging (rsfMRI) to investigate whole-brain networks in patients with...

INTRODUCTION Numerous differences between males and females in brain organization have been described including in the development, performance, and lateralization of language function. However, there is very limited knowledge of whether language processing differs across sex in patients with brain lesions. In particular, malignant brain tumors (MB...

Background and Objective Prolactinomas may cause drastic hormone fluctuations throughout the body. It is not fully understood how endogenous hormone disorders such as prolactinomas reshape the patient’s brain. By employing the resting-state functional magnetic resonance imaging technique, we aimed to investigate the whole-brain functional connectiv...

Purpose Brain shift during tumor resection can progressively invalidate the accuracy of neuronavigation systems and affect neurosurgeons’ ability to achieve optimal resections. This paper compares two methods that have been presented in the literature to compensate for brain shift: a thin-plate spline deformation model and a finite element method (...

INTRODUCTION Numerous differences between males and females in brain organization have been described including in the development, performance, and lateralization of language function. However, there is very limited knowledge of whether language processing differs across sex in patients with brain lesions. In particular, malignant brain tumors (MB...

Fluorescence guided surgery (FGS) has fueled the development of novel technologies aimed at maximizing the utility of fluorescence imaging to help clinicians diagnose and in certain cases treat diseases across a breadth of disciplines such as dermatology, gynecology, oncology, ophthalmology, and neurosurgery. In neurosurgery, the goal of FGS techno...

Brain shift compensation attempts to model the deformation of the brain which occurs during the surgical removal of brain tumors to enable mapping of presurgical image data into patient coordinates during surgery and thus improve the accuracy and utility of neuro-navigation. We present preliminary results from clinical tumor resections that compare...

In present study, we investigated the in vitro antioxidant and free radical scavenging activities of crude methanolic and aqueous extract of Indigofera cordifolia (Fabaceae) seeds. The antioxidant and free radical-scavenging activities of Indigofera cordifolia seed extracts were evaluated using different tests involving inhibition of DPPH, ABTS, TB...

This study was designed to evaluate the anti-inflammatory activity of aqueous and 70% methanolic extracts of pollen grains of Typha angustifolia. Female Sprague Dawley rats were used for the study. The acute anti-inflammatory activity of pollen grains of T. angustifolia was studied using the carrageenan as phlogistic agent, whereas its chronic anti...

In the present study, aqueous extract of Avicennia officinalis was screened for lipid peroxidation inhibitory and anti-arthritic activities using standard in vitro procedures. It exhibited important free radical-scavenging activity towards the lipid peroxidation and DPPH radicals. A. officinalis also revealed moderate anti-arthritic activity. Folin...

Anti-lipid peroxidation effect of aqueous extracts of Ocimum sanctum, Tinospora cordifolia and Withania somnifera was evaluated against Fe 2+-ascorbic acid-induced lipid peroxidation using rat liver mitochondria as model system, whereas, anti-arthritic activity was evaluated by proteinase inhibitory assay. O. sanctum showed potent anti-lipid peroxi...

The aim of present in vitro study was to investigate antioxidant and anti-arthritic activities of Shilajit. The antioxidant activity of aqueous extract of Shilajit was determined by using 3 in vitro parameters, namely, DPPH radical-scavenging assay, lipid peroxidation inhibitory assay and reducing power assay, whereas, anti-arthritic activity was e...

Introduction: Oxidative stress resulted from free radicals and reactive oxygen species are associated with many diseases. Several studies are going on worldwide directed towards finding natural antioxidants of plant origin. Plants containing phenolic compounds have been reported to possess strong antioxidant activity. The aim of the present study w...