Kenneth P Vives

Columbia University, New York City, NY, United States

Are you Kenneth P Vives?

Claim your profile

Publications (35)85.73 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Intracranial EEG (icEEG) provides a critical road map for epilepsy surgery but has become increasingly difficult to interpret as technology has allowed the number of icEEG channels to grow. Borrowing methods from neuroimaging, we aimed to simplify data analysis and increase consistency between reviewers by using 3D Surface Projections of Intracranial EEG poweR (3D-SPIER). We analyzed 139 seizures from 48 intractable epilepsy patients (28 temporal and 20 extratemporal) who had icEEG recordings, epilepsy surgery, and at least one year of post-surgical follow-up. We coregistered and plotted icEEG β frequency band signal power over time onto MRI-based surface renderings for each patient, to create color 3D-SPIER movies. Two independent reviewers interpreted the icEEG data using visual analysis vs. 3D-SPIER, blinded to any clinical information. Overall agreement rates between 3D-SPIER and icEEG visual analysis or surgery were about 90% for side of seizure onset, 80% for lobe, and just under 80% for sublobar localization. These agreement rates were improved when flexible thresholds or frequency ranges were allowed for 3D SPIER, especially for sublobar localization. Interestingly, agreement was better for patients with good surgical outcome than for patients with poor outcome. Localization using 3D-SPIER was measurably faster and considered qualitatively easier to interpret than visual analysis. These findings suggest that 3D-SPIER could be an improved diagnostic method for presurgical seizure localization in patients with intractable epilepsy and may also be useful for mapping normal brain function.
    NeuroImage 07/2013; · 6.25 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: During neurosurgery, nonrigid brain deformation may affect the reliability of tissue localization based on preoperative images. To provide accurate surgical guidance in these cases, preoperative images must be updated to reflect the intraoperative brain. This can be accomplished by warping these preoperative images using a biomechanical model. Due to the possible complexity of this deformation, intraoperative information is often required to guide the model solution. In this paper, a linear elastic model of the brain is developed to infer volumetric brain deformation associated with measured intraoperative cortical surface displacement. The developed model relies on known material properties of brain tissue, and does not require further knowledge about intraoperative conditions. To provide an initial estimation of volumetric model accuracy, as well as determine the model's sensitivity to the specified material parameters and surface displacements, a realistic brain phantom was developed. Phantom results indicate that the linear elastic model significantly reduced localization error due to brain shift, from > 16 mm to under 5 mm, on average. In addition, though in vivo quantitative validation is necessary, preliminary application of this approach to images acquired during neocortical epilepsy cases confirms the feasibility of applying the developed model to in vivo data.
    IEEE transactions on medical imaging. 05/2012; 31(8):1607-19.
  • [Show abstract] [Hide abstract]
    ABSTRACT: During neurosurgery, nonrigid brain deformation may affect the reliability of tissue localization based on preoperative images. To provide accurate surgical guidance in these cases, preoperative images must be updated to reflect the intraoperative brain. This can be accomplished by warping these preoperative images using a biomechanical model. Due to the possible complexity of this deformation, intraoperative information is often required to guide the model solution. In this paper, a linear elastic model of the brain is developed to infer volumetric brain deformation associated with measured intraoperative cortical surface displacement. The developed model relies on known material properties of brain tissue, and does not require further knowledge about intraoperative conditions. To provide an initial estimation of volumetric model accuracy, as well as determine the model's sensitivity to the specified material parameters and surface displacements, a realistic brain phantom was developed. Phantom results indicate that the linear elastic model significantly reduced localization error due to brain shift, from >; 16 mm to under 5 mm, on average. In addition, though in vivo quantitative validation is necessary, preliminary application of this approach to images acquired during neocortical epilepsy cases confirms the feasibility of applying the developed model to in vivo data.
    IEEE Transactions on Medical Imaging 01/2012; 31(8):1607-1619. · 4.03 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Image-guided neurosurgery requires navigation in 3D using a computer-assisted surgery system that tracks surgical tools in realtime and displays their positions with respect to the preoperatively acquired images (e.g. CT, MRI, fMRI etc.) A key problem in image guided procedures is the need to navigate to specific locations highlighted in the images, such as image-derived functional areas, that have no obvious corresponding anatomical landmarks - we refer to such locations as virtual landmarks. To address these issues, we contribute a novel interactive visualization technique to provide improved feedback to surgeons - Augmented inline visualization. Based on the results of an expert evaluation, we found neurosurgeons to be 30% more accurate when using our augmented inline representation.
    Proceedings / IEEE International Symposium on Biomedical Imaging: from nano to macro. IEEE International Symposium on Biomedical Imaging 03/2011;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Images with missing correspondences are difficult to align using standard registration methods due to the assumption that the same features appear in both images. To address this problem in brain resection images, we have recently proposed an algorithm in which the registration process is aided by an indicator map that is simultaneously estimated to distinguish between missing and valid tissue. We now extend our method to include both intensity and location information for the missing data. We introduce a prior on the indicator map using a Markov random field (MRF) framework to incorporate map smoothness and spatial knowledge of the missing correspondences. The parameters for the indicator map prior are automatically estimated along with the transformation and indicator map. The new method improves both segmentation and registration accuracy as demonstrated using synthetic and real patient data.
    Proceedings of the 8th IEEE International Symposium on Biomedical Imaging: From Nano to Macro, ISBI 2011, March 30 - April 2, 2011, Chicago, Illinois, USA; 01/2011
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Impaired consciousness requires altered cortical function. This can occur either directly from disorders that impair widespread bilateral regions of the cortex or indirectly through effects on subcortical arousal systems. It has therefore long been puzzling why focal temporal lobe seizures so often impair consciousness. Early work suggested that altered consciousness may occur with bilateral or dominant temporal lobe seizure involvement. However, other bilateral temporal lobe disorders do not impair consciousness. More recent work supports a 'network inhibition hypothesis' in which temporal lobe seizures disrupt brainstem-diencephalic arousal systems, leading indirectly to depressed cortical function and impaired consciousness. Indeed, prior studies show subcortical involvement in temporal lobe seizures and bilateral frontoparietal slow wave activity on intracranial electroencephalography. However, the relationships between frontoparietal slow waves and impaired consciousness and between cortical slowing and fast seizure activity have not been directly investigated. We analysed intracranial electroencephalography recordings during 63 partial seizures in 26 patients with surgically confirmed mesial temporal lobe epilepsy. Behavioural responsiveness was determined based on blinded review of video during seizures and classified as impaired (complex-partial seizures) or unimpaired (simple-partial seizures). We observed significantly increased delta-range 1-2 Hz slow wave activity in the bilateral frontal and parietal neocortices during complex-partial compared with simple-partial seizures. In addition, we confirmed prior work suggesting that propagation of unilateral mesial temporal fast seizure activity to the bilateral temporal lobes was significantly greater in complex-partial than in simple-partial seizures. Interestingly, we found that the signal power of frontoparietal slow wave activity was significantly correlated with the temporal lobe fast seizure activity in each hemisphere. Finally, we observed that complex-partial seizures were somewhat more common with onset in the language-dominant temporal lobe. These findings provide direct evidence for cortical dysfunction in the form of bilateral frontoparietal slow waves associated with impaired consciousness in temporal lobe seizures. We hypothesize that bilateral temporal lobe seizures may exert a powerful inhibitory effect on subcortical arousal systems. Further investigations will be needed to fully determine the role of cortical-subcortical networks in ictal neocortical dysfunction and may reveal treatments to prevent this important negative consequence of temporal lobe epilepsy.
    Brain 11/2010; 133(Pt 12):3764-77. · 9.92 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An abstract is unavailable. This article is available as HTML full text and PDF.
    Neurosurgery 07/2010; 67(2):556. · 2.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present a technique for enhancing multimodal visualizations for image-guided neurosurgery in the presence of adverse lighting conditions. In the surgical environment, images used for real time navigation are displayed in suboptimal conditions due to the varying lighting conditions. Our approach actively monitors the incoming light on the display and appropriately enhances the visualization based on the change in light. Based on the results of a user study to evaluate our approach, we found that our enhanced visualization techniques were mostly preferred over regular visualizations.
    Proceedings / IEEE International Symposium on Biomedical Imaging: from nano to macro. IEEE International Symposium on Biomedical Imaging 06/2010;
  • [Show abstract] [Hide abstract]
    ABSTRACT: We present a technique for enhancing multimodal visualizations for image-guided neurosurgery in the presence of adverse lighting conditions. In the surgical environment, images used for real time navigation are displayed in suboptimal conditions due to the varying lighting conditions. Our approach actively monitors the incoming light on the display and appropriately enhances the visualization based on the change in light. Based on the results of a user study to evaluate our approach, we found that our enhanced visualization techniques were mostly preferred over regular visualizations.
    Biomedical Imaging: From Nano to Macro, 2010 IEEE International Symposium on; 05/2010
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: During neurosurgery, nonrigid brain deformation prevents preoperatively-acquired images from accurately depicting the intraoperative brain. Stereo vision systems can be used to track intraoperative cortical surface deformation and update preoperative brain images in conjunction with a biomechanical model. However, these stereo systems are often plagued with calibration error, which can corrupt the deformation estimation. In order to decouple the effects of camera calibration from the surface deformation estimation, a framework that can solve for disparate and often competing variables is needed. Game theory, which was developed to handle decision making in this type of competitive environment, has been applied to various fields from economics to biology. In this paper, game theory is applied to cortical surface tracking during neocortical epilepsy surgery and used to infer information about the physical processes of brain surface deformation and image acquisition. The method is successfully applied to eight in vivo cases, resulting in an 81% decrease in mean surface displacement error. This includes a case in which some of the initial camera calibration parameters had errors of 70%. Additionally, the advantages of using a game theoretic approach in neocortical epilepsy surgery are clearly demonstrated in its robustness to initial conditions.
    IEEE transactions on medical imaging. 02/2010; 29(2):322-38.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Vectors derived from adeno-associated virus (AAV) are promising candidates for neural cell transduction in vivo because they are nonpathogenic and achieve long-term transduction in the central nervous system. AAV serotype 2 (AAV2) is the most widely used AAV vector in clinical trials based largely on its ability to transduce neural cells in the rodent and primate brain. Prior work in rodents suggests that other serotypes might be more efficient; however, a systematic evaluation of vector transduction efficiency has not yet been performed in the primate brain. In this study, AAV viral vectors of serotypes 1–6 with an enhanced green-fluorescent protein (GFP) reporter gene were generated at comparable titers, and injected in equal amounts into the brains of Chlorocebus sabaeus. Vector injections were placed in the substantia nigra (SN) and the caudate nucleus (CD). One month after injection, immunohistochemistry for GFP was performed and the total number of GFP+ cells was calculated using unbiased stereology. AAV5 was the most efficient vector, not only transducing significantly more cells than any other serotype, but also transducing both NeuN+ and glial-fibrillary-acidic protein positive (GFAP+) cells. These results suggest that AAV5 is a more effective vector than AAV2 at delivering potentially therapeutic transgenes to the nigrostriatal system of the primate brain.
    Molecular Therapy 12/2009; 18(3):588-593. · 7.04 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper describes the development and application of a research interface to integrate research image analysis software with a commercial image-guided surgery navigation system. This interface enables bi-directional transfer of data such as images, visualizations and tool positions in real time. We describe both the design and the application programming interface of the research interface, as well as showing the function of an example client program. The resulting interface provides a practical and versatile link for bringing image analysis research techniques into the operating room (OR). We present examples from the successful use of this research interface in both phantom experiments and real neurosurgeries. In particular, we demonstrate that the integrated dual-computer system achieves tool-tracking performance that is comparable to the more typical single-computer scenario. Network interfaces for this type are viable solutions for the integration of commercial image-guided navigation systems and research software.
    International Journal of Medical Robotics and Computer Assisted Surgery 03/2009; 5(2):147-57. · 1.49 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Neurosurgical planning and image guided neurosurgery require the visualization of multimodal data obtained from various functional and structural image modalities, such as Magnetic Resonance Imaging (MRI), Computed Tomography (CT), functional MRI, Single photon emission computed tomography (SPECT) and so on. In the case of epilepsy neurosurgery for example, these images are used to identify brain regions to guide intracranial electrode implantation and resection. Generally, such data is visualized using 2D slices and in some cases using a 3D volume rendering along with the functional imaging results. Visualizing the activation region effectively by still preserving sufficient surrounding brain regions for context is exceedingly important to neurologists and surgeons. We present novel interaction techniques for visualization of multimodal data to facilitate improved exploration and planning for neurosurgery. We extended the line widget from VTK to allow surgeons to control the shape of the region of the brain that they can visually crop away during exploration and surgery. We allow simple spherical, cubical, ellipsoidal and cylindrical (probe aligned cuts) for exploration purposes. In addition we integrate the cropping tool with the image-guided navigation system used for epilepsy neurosurgery. We are currently investigating the use of these new tools in surgical planning and based on further feedback from our neurosurgeons we will integrate them into the setup used for image-guided neurosurgery.
    IEEE Transactions on Visualization and Computer Graphics 01/2009; 14(6):1587-94. · 1.90 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Neural transplantation offers the potential of treating Parkinson's disease by grafting fetal dopamine neurons to depleted regions of the brain. However, clinical studies of neural grafting in Parkinson's disease have produced only modest improvements. One of the main reasons for this is the low survival rate of transplanted neurons. The inadequate supply of critical neurotrophic factors in the adult brain is likely to be a major cause of early cell death and restricted outgrowth of fetal grafts placed into the mature striatum. Glial derived neurotrophic factor (GDNF) is a potent neurotrophic factor that is crucial to the survival, outgrowth and maintenance of dopamine neurons, and so is a candidate for protecting grafted fetal dopamine neurons in the adult brain. We found that implantation of adeno-associated virus type 2 encoding GDNF (AAV2-GDNF) in the normal monkey caudate nucleus induced overexpression of GDNF that persisted for at least 6 months after injection. In a 6-month within-animal controlled study, AAV2-GDNF enhanced the survival of fetal dopamine neurons by 4-fold, and increased the outgrowth of grafted fetal dopamine neurons by almost 3-fold in the caudate nucleus of MPTP-treated monkeys, compared with control grafts in the other caudate nucleus. Thus, the addition of GDNF gene therapy to neural transplantation may be a useful strategy to improve treatment for Parkinson's disease.
    Experimental Neurology 06/2008; 211(1):252-8. · 4.65 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Temporal lobe epilepsy (TLE) is associated with smaller hippocampal volume and with elevated extracellular (EC) glutamate levels. We investigated the relationship between the hippocampal volume and glutamate in refractory TLE patients. We used quantitative MRI volumetrics to measure the hippocampal volume and zero-flow microdialysis to measure the interictal glutamate, glutamine, and GABA levels in the epileptogenic hippocampus of 17 patients with medication-resistant epilepsy undergoing intracranial EEG evaluation. The relationships between hippocampal volume, neurochemical levels, and relevant clinical factors were examined. Increased EC glutamate in the epileptogenic hippocampus was significantly related to smaller ipsilateral (R(2)= 0.75, p < 0.0001), but not contralateral hippocampal volume when controlled for glutamine and GABA levels, and for clinical factors known to influence hippocampal volume. Glutamate in the atrophic hippocampus was significantly higher (p = 0.008, n = 9), with the threshold for hippocampal atrophy estimated as 5 microM. GABA and glutamine levels in the atrophic and nonatrophic hippocampus were comparable. Decreased hippocampal volume was related to higher seizure frequency (p = 0.008), but not to disease duration or febrile seizure history. None of these clinical factors were related to the neurochemical levels. We provide evidence for a significant association between increased EC glutamate and decreased ipsilateral epileptogenic hippocampal volume in TLE. Future work will be needed to determine whether the increase in glutamate has a causal relationship with hippocampal atrophy, or whether another, yet unknown factor results in both. This work has implications for the understanding and treatment of epilepsy as well as other neurodegenerative disorders associated with hippocampal atrophy.
    Epilepsia 05/2008; 49(8):1358-66. · 3.96 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Cortical stimulation to abort seizures is under human investigation. Ideal electrode placement and stimulating parameters are unknown with poor understanding of tissue volume affected by stimulation or duration and nature of its effect on cortical activity. To help characterize this effect, we analyzed electrocorticography (ECoG) recorded adjacent to stimulated contacts during and after bipolar stimulation in patients undergoing functional cortical mapping with subdural electrodes. We analyzed four functional mapping procedures in three patients. One row of contacts was chosen for bipolar stimulation at sequential distances. Stimulation parameters were those used for functional mapping. Pooled Teager energy (TE) and band power were calculated for: (1) baseline, (2) 5 s during stimulation, and (3) 5-15 s after the stimulus. Average TE increased during stimulation, falling with distance from the stimulus. Average poststimulus TE increased (284-905%) compared to baseline. Increased TE was observed: (1) up to 10 s after stimulation, (2) stimulation amplitudes of 4 mA or greater, and (3) up to 2 cm from the stimulus. There was no difference in poststimulus TE between the stimulated pair of contacts and outside the pair. Greatest increase in poststimulus signal power occurred in beta and gamma bands. Human cortical stimulation of 50 Hz resulted in elevated ECoG energy measurements up to 10 s poststimulation. Contacts >2 cm from stimulated electrodes did not show significant response to stimulation. Separating contacts >2 cm on the cortical surface may not result in efficacious treatment of seizure activity using common stimulation amplitudes (2-10 mA).
    Epilepsia 04/2008; 49(9):1602-10. · 3.96 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The goal of this work was to evaluate the relationship between neuronal injury/loss in the hippocampus, thalamus, and putamen in temporal lobe epilepsy (TLE) patients using (1)H magnetic resonance spectroscopic imaging. (1)H spectroscopic images from the hippocampus and thalamus of controls and patients with TLE were acquired at 4 T. The spectroscopic imaging data were reconstructed using an automated voxel-shifting method based on anatomic landmarks providing four, six, and three loci for the hippocampus, thalamus, and putamen, respectively. For correlation analysis, the hippocampal and striatal loci were averaged to provide single estimates of the entire structure, whereas the thalamus was divided into two regions, an anterior and posterior measure, using the average of three loci each. The ratio of N-acetyl aspartate to creatine (NAA/Cr), a measure of neuronal injury/loss, was significantly reduced in both the ipsilateral and contralateral hippocampi and thalami. NAA/Cr in the ipsilateral hippocampus was significantly correlated with the ipsilateral and contralateral anterior and posterior thalami, putamen, and contralateral hippocampus. In control subjects, the hippocampi were only correlated with each other. The data demonstrate that there is significant neuronal injury/loss in both the ipsilateral and contralateral thalami in temporal lobe epilepsy patients, with greater impairment in the anterior portions of the ipsilateral thalamus. The degree of injury/loss in the ipsilateral and contralateral thalamus and putamen is directly correlated with that of the ipsilateral hippocampus. This is consistent with the hypothesis that the impairment and damage associated with recurrent seizures as measured by N-acetyl aspartate originating in the hippocampus results in injury and impairment in other subcortical structures.
    Neurology 01/2008; 69(24):2256-65. · 8.25 Impact Factor
  • Journal of Neuro-Oncology 01/2008; 85(3):289-90. · 3.12 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: During neurosurgery, brain deformation renders preoperative images unreliable for localizing pathologic structures. In order to visualize the current brain anatomy, it is necessary to nonrigidly warp these preoperative images to reflect the intraoperative brain. This can be accomplished using a biomechanical model driven by sparse intraoperative information. In this paper, a linear elastic model of the brain is developed which can infer volumetric brain deformation given the cortical surface displacement. This model was tested on both a realistic brain phantom and in vivo, proving its ability to account for large brain deformations. Also, an efficient semiautomatic strategy for preoperative cortical feature detection is outlined, since accurate segmentation of cortical features can aid intraoperative cortical surface tracking.
    Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention. 02/2007; 10(Pt 2):553-61.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: During neurosurgery, nonrigid brain deformation prevents preoperatively acquired images from accurately depicting the intraoperative brain. Stereo vision systems can be used to track cortical surface deformation and update preoperative brain images in conjunction with a biomechanical model. However, these stereo systems are often plagued with calibration error, which can corrupt the deformation estimation. In order to decouple the effects of camera calibration and surface deformation, a framework is needed which can solve for disparate and often competing variables. Game theory, which was developed specifically to handle decision making in this type of competitive environment, has been applied to various fields from economics to biology. In this paper, we apply game theory to cortical surface tracking and use it to infer information about the physical processes of brain deformation and image acquisition.
    IEEE 11th International Conference on Computer Vision, ICCV 2007, Rio de Janeiro, Brazil, October 14-20, 2007; 01/2007

Publication Stats

354 Citations
85.73 Total Impact Points

Institutions

  • 2012
    • Columbia University
      • Department of Psychiatry
      New York City, NY, United States
  • 1999–2010
    • Yale University
      • • Department of Biomedical Engineering
      • • Department of Diagnostic Radiology and Pediatric Diagnostic Radiology
      • • Department of Neurosurgery
      New Haven, CT, United States
  • 1997–2010
    • Yale-New Haven Hospital
      • • Department of Laboratory Medicine
      • • Department of Pathology
      New Haven, Connecticut, United States