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[IEEE 2018 IEEE International Symposium on Medical Measurements and Applications (MeMeA) - Rome, Italy (2018.6.11-2018.6.13)] 2018 IEEE International Symposium on Medical Measurements and Applications (MeMeA) - Extracting Features from Optical Coherence Tomography for Measuring Optical Nerve Thickness
摘要： Neurological pathologies, especially optical neuropathologies, can be studied by means of OCT (optical coherence tomography). Tomography generally allows to investigate inner structures of a tissue such as mass, and profiles of liquid flow. OCT is intended as an interferometry-based imaging technique that provides cross-sectional views of substrates. It allows to measure micro-scale cross-sectional imaging of biological tissue. While ultrasound uses sound waves, it acts like it but with a low coherence light. Optical nerve thickness has an impact on different neurological pathologies, and in particular as an indicator of epilepsy. We propose a dedicated technique for measuring optical nerve thickness and identifying its quality by means of processing front eye image in nanoscale. Experimental measurements have been performed, and a database of 10 teenagers has been used for that.
关键词： Micro and Nanotechnology,Optical nerve thickness measurement,Optical coherence Tomography,Neuro-disorders,Epilepsy,Atomic Force Microscopy,EEG
更新于2025-09-23 15:22:29
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Non-invasive Seizure Localization with Ictal Single-Photon Emission Computed Tomography is Impacted by Preictal/Early Ictal Network Dynamics
摘要： More than one third of children with epilepsy have medically intractable seizures. Promising therapies, including targeted neurostimulation and surgery, depend on accurate localization of the epileptogenic zone. Ictal perfusion Single-Photon Emission Computed Tomography (SPECT) can localize the seizure focus noninvasively, with comparable accuracy to that of invasive EEG. However, multiple factors including seizure dynamics may affect its spatial specificity. Methods: Using subtracted ictal from interictal SPECT and scalp EEG from 118 pediatric epilepsy patients (40 of whom had surgery after the SPECT studies), information theoretic measures of association and advanced statistical models, this study investigated the impact of preictal and ictal brain network dynamics on SPECT focality. Results: Network dynamics significantly impacted the SPECT localization ～30 s before to ～45 s following ictal onset. Distributed early ictal connectivity changes, indicative of a rapidly evolving seizure, were negatively associated with SPECT focality. Spatially localized connectivity changes later in the seizure, indicating slower seizure propagation, were positively associated with SPECT focality. In the first ～60 s of the seizure, significantly higher network connectivity was estimated in an area overlapping with the area of hyperperfusion. Finally, ～75% of patients with Engel class 1a/1b outcomes had SPECTs that were concordant with the resected area. Conclusion: Slowly evolving seizures are more likely to be accurately imaged with SPECT, and the identified focus may overlap with brain regions where significant topological changes occur. Significance: Measures of preictal/early ictal network dynamics may help optimize the SPECT localization, leading to improved surgical and neurostimulation outcomes in refractory epilepsy.
关键词： ictal SPECT,noninvasive source localization,brain networks,Epilepsy
更新于2025-09-23 15:21:21
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Highly realistic simulation for robot-assisted hypothalamic hamartoma real-time MRI-guided laser interstitial thermal therapy (LITT)
摘要： Purpose Real-time MRI-guided laser interstitial thermal therapy (LITT) is a challenging procedure due to its technical complexity, as well as the need for efficient multidisciplinary teamwork and transfer of an anesthetized patient between operating room (OR) and magnetic resonance (MR). A highly realistic simulation was developed to design the safest process before being applied to real patients. In this report, authors address the description of the methodology used for this simulation and its purposefulness. Methods The entire image planning, anesthetic, and surgical process were performed on a modified pediatric simulation mannequin with a brain made of medical grade silicone including a hypothalamic hamartoma. Preoperative CT and MR were acquired. Stereotactic insertion of the optical fiber was assisted by the Neuromate? stereotactic robot. Laser ablation was performed with the Medtronic Visualase? MRI-guided system in a 3T Phillips Ingenia? MR scanner. All the stages of the process, participants, and equipment were the same as planned for a real surgery. Results No critical errors were found in the process design that prevented the procedure from being performed with adequate safety. Specific proposals for team positioning and interaction in patient transfers and in MR room were validated. Some specific elements that could improve safety were identified. Conclusion Highly realistic simulation has been an extremely useful tool for safely planning LITT, because professionals were able to take actions in the workflow based not on ideas but on lived experiences. It contributed definitively to build a well-coordinated surgical team that worked safely and more efficiently.
关键词： Robotic surgery,Patient safety,Pediatric epilepsy surgery,Risk management,Laser ablation
更新于2025-09-23 15:19:57
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Comparison of optic coherence tomography results in patients with diagnosed epilepsy: Findings in favor of neurodegeneration
摘要： Background: Epilepsy is a chronic neurological disease characterized with recurrent seizures. Progressive neuronal degeneration is a common consequence of long-term and/or recurrent seizure activity in epilepsy. Optical coherence tomography (OCT) is a new medical imaging technique that displays biological tissue layers as high-resolution tomographic sections. The aim of our study was to evaluate OCT findings in patients with epilepsy and to compare OCT findings in terms of disease duration, presence of status, seizure frequency, and drug use. Methods: Forty-three patients who had epilepsy according to the Commission on Classification and Terminology of the International League Against Epilepsy (ILAE) in 2010 and 40 healthy controls were recruited for the study. Disease duration, seizure frequency, status history, and multiple drug use were noted. Retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner-plexiform layer (IPL), and choroid thinning were analyzed by using spectral OCT. Results: The mean RNFL values are 101.48 ± 11.33 in the patient group and 108.76 ± 8.37 in the control group (p = 0.001). The mean GCL thickness values in the patient and control groups are 1.14 ± 0.12 and 1.22 ± 0.05, (p < 0.001). The mean IPL thickness is 0.93 ± 0.09 in the patient group and 0.97 ± 0.05 in the control group (p = 0.02). Choroid thickness is significantly increased in the patient group (p < 0.001). Conclusions: Demonstration of RNFL, IPL, and GCL thinning might indicate neurodegeneration, and choroid thickening indicates neuroinflammation. We found no association between disease duration, seizure frequency, status history, and multiple drug use and OCT parameters. Further studies with larger patient groups should clarify the matter.
关键词： Retinal nerve fiber layer,Optic coherence tomography,Choroidal thickness,Ganglion cell layer,Epilepsy
更新于2025-09-19 17:15:36
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[IEEE 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Guangzhou, China (2019.5.19-2019.5.22)] 2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT) - Research on High Directional Waveguide Directional Coupler
摘要： In this paper, we developed a model-based and a data-driven estimator for directed information (DI) to infer the causal connectivity graph between electrocorticographic (ECoG) signals recorded from brain and to identify the seizure onset zone (SOZ) in epileptic patients. DI, an information theoretic quantity, is a general metric to infer causal connectivity between time series and is not restricted to a particular class of models unlike the popular metrics based on Granger causality or transfer entropy. The proposed estimators are shown to be almost surely convergent. Causal connectivity between ECoG electrodes in five epileptic patients is inferred using the proposed DI estimators, after validating their performance on simulated data. We then proposed a model-based and a data-driven SOZ identification algorithm to identify SOZ from the causal connectivity inferred using the model-based and data-driven DI estimators, respectively. The data-driven SOZ identification outperforms the model-based SOZ identification algorithm when benchmarked against the visual analysis by neurologist, the current clinical gold standard. The causal connectivity analysis presented here is the first step toward developing novel nonsurgical treatments for epilepsy.
关键词： ECoG,seizure onset zone,epilepsy,directed information,Causal connectivity
更新于2025-09-19 17:13:59
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Staged Magnetic Resonance-Guided Laser Interstitial Thermal Therapy for Hypothalamic Hamartoma: Analysis of Ablation Volumes and Morphological Considerations
摘要： BACKGROUND: Hypothalamic hamartomas (HH) are a challenging pathology that cause gelastic seizures. Magnetic Resonance Imaging-guided Laser Interstitial Thermal Therapy (MRgLITT) offers a safe and effective treatment for HHs via a minimally invasive technique. OBJECTIVE: To determine how clinical outcome correlates to residual tumor volume and surgical strategy by analyzing radiographic data and reconstructing volumetric imaging. METHODS: Clinical and radiographic information of 58 pediatric patients who underwent MRgLITT for HH with at least 6 mo of follow-up were retrospectively reviewed. MR imaging was volumetrically reconstructed to analyze the impact of hamartoma and ablation volumes on outcome. Primary outcome measure was freedom from gelastic seizures. RESULTS: Eighty-one percent of patients were completely free of gelastic seizures at last follow-up; of 22 patients with secondary nongelastic epilepsy, 15 were free of additional seizures. Postoperative complication rate was low. There was no significant difference in gelastic seizure outcome related to pre- or postoperative hamartoma size. Residual hamartoma percentage in those free of gelastic seizures was 43% compared to 71% in those with continued seizures (P = .021). Larger hamartomas required multiple ablations to achieve seizure freedom. CONCLUSION: This large series of patients confirms the safety and efficacy of MRgLITT for pediatric HH and describes morphological considerations that predict success. Our data suggest that complete ablation of the lesion is not necessary, and that the focus should be on appropriate disconnection of the epileptogenic network. We have found that a staged approach to hamartoma ablation allows adequate disconnection of the hamartoma while mitigating risk to surrounding structures.
关键词： Epilepsy,Laser ablation,Hypothalamic hamartoma,Gelastic seizures,Laser interstitial thermal therapy
更新于2025-09-19 17:13:59
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Laser microdissection-based microproteomics of the hippocampus of a rat epilepsy model reveals regional differences in protein abundances
摘要： Mesial temporal lobe epilepsy (MTLE) is a chronic neurological disorder affecting almost 40% of adult patients with epilepsy. Hippocampal sclerosis (HS) is a common histopathological abnormality found in patients with MTLE. HS is characterised by extensive neuronal loss in different hippocampus sub-regions. In this study, we used laser microdissection-based microproteomics to determine the protein abundances in different regions and layers of the hippocampus dentate gyrus (DG) in an electric stimulation rodent model which displays classical HS damage similar to that found in patients with MTLE. Our results indicate that there are differences in the proteomic profiles of different layers (granule cell and molecular), as well as different regions, of the DG (ventral and dorsal). We have identified new signalling pathways and proteins present in specific layers and regions of the DG, such as PARK7, RACK1, and connexin 31/gap junction. We also found two major signalling pathways that are common to all layers and regions: inflammation and energy metabolism. Finally, our results highlight the utility of high-throughput microproteomics and spatial-limited isolation of tissues in the study of complex disorders to fully appreciate the large biological heterogeneity present in different cell populations within the central nervous system.
关键词： microproteomics,rat epilepsy model,hippocampus,protein abundances,Laser microdissection,PARK7,energy metabolism,connexin 31/gap junction,RACK1,inflammation
更新于2025-09-19 17:13:59
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Comparison of Perioperative Costs between Stereotactic Laser Ablation and Craniotomy for Hypothalamic Hamartoma
摘要： Hypothalamic hamartoma (HH) is a congenital intracranial lesion associated with precocious puberty and gelastic epilepsy in children. Surgical management of HH to treat refractory epilepsy is a mainstay of treatment. Our aim was to compare the demographic characteristics and perioperative costs associated with resection by craniotomy and stereotactic laser ablation (SLA) by reviewing our institutional experience with SLA and comparing these data to a national database for craniotomy and resection. Retrospective chart review was conducted for the Texas Children’s Hospital cohort of patients who underwent SLA for HH between 2011 and 2013. Information about the craniotomy cohort representing historical cases of craniotomy was obtained from the Kids’ Inpatient Database for years 2003, 2006, and 2009. The cohort definition for patients undergoing craniotomy for HH was modified from published adult literature to identify pediatric patients with refractory epilepsy secondary to HH. Our study has shown that children undergoing SLA for HH have a shorter length of stay and lower cost of hospitalization compared with those who underwent craniotomy and resection for the same diagnosis. Together with previous findings from our institution regarding the safety and efficacy of SLA, our findings suggest that SLA may represent an attractive alternative to craniotomy for the treatment of refractory epilepsy secondary to HH.
关键词： hypothalamic hamartoma,epilepsy,hospitalization charges,gelastic seizures,stereotactic ablation,laser ablation,cost
更新于2025-09-16 10:30:52
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Cognitive outcomes following laser interstitial therapy for mesiotemporal epilepsies
摘要： Objective To provide a review of cognitive outcomes across a full neuropsychological profile in patients who underwent laser interstitial thermal therapy (LiTT) for mesiotemporal epilepsy (mTLE). Methods We examined cognitive outcomes following LiTT for mTLE by reviewing a consecutive series of 26 patients who underwent dominant or nondominant hemisphere procedures. Each patient’s pre- and postsurgical performance was examined for clinically significant change (>1SD improvement or decline on standardized scores), with a neuropsychologic battery that included measures of language, memory, executive functioning, and processing speed. Results Presurgical performance was largely consistent with previous research, where patients suffering from dominant hemisphere epilepsies demonstrated deficits in verbal learning and memory, whereas patients with nondominant hemisphere scored lower on visually mediated tests. Case-by-case review comparing presurgical to postsurgical scores revealed clinically significant improvement in both dominant and nondominant patients in learning and memory and other aspects of cognition such as processing speed and executive functioning. Of the few patients who did experience clinically significant decline following LiTT, a greater proportion had undergone dominant hemisphere procedures. Conclusions Compared with the outcome literature of dominant open anterior temporal lobectomies (ATLs), where postsurgical decline has been documented in up to 40%–60% of cases, our LiTT case series exhibited a much lower incidence of postoperative language or verbal memory decline. Moreover, promising rates of postoperative improvements were also observed across multiple cognitive domains. Future studies exploring cognitive outcomes following LiTT should include comprehensive neuropsychological findings, rather than only select domains, as clinically significant change can occur in areas other than those typically associated with mesiotemporal structures.
关键词： cognitive outcomes,mesiotemporal epilepsy,laser interstitial thermal therapy,neuropsychological profile
更新于2025-09-16 10:30:52
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Lesion Network Localization of Seizure Freedom following MR-guided? Laser Interstitial Thermal Ablation
摘要： treatment-resistant epilepsy is a common and debilitating neurological condition, for which neurosurgical cure is possible. Despite undergoing nearly identical ablation procedures however, individuals with treatment-resistant epilepsy frequently exhibit heterogeneous outcomes. We hypothesized that treatment response may be related to the brain regions to which MR-guided laser ablation volumes are functionally connected. to test this, we mapped the resting-state functional connectivity of surgical ablations that either resulted in seizure freedom (N =?11)?or?did?not?result in seizure freedom (N =?16)?in?over?1,000?normative?connectomes.?There?was?no?difference?seizure outcome with respect to the anatomical location of the ablations, and very little overlap between ablation?areas?was?identified?using?the?Dice?Index.?Ablations?that?did?not?result?in?seizure-freedom?were preferentially connected to a number of cortical and subcortical regions, as well as multiple canonical resting-state networks. in contrast, ablations that led to seizure-freedom were more functionally connected to prefrontal cortices. Here, we demonstrate that underlying normative neural circuitry may?in?part?explain?heterogenous?outcomes?following?ablation?procedures?in?different?brain?regions. These?findings?may?ultimately?inform?target?selection?for?ablative?epilepsy?surgery?based?on?normative intrinsic connectivity of the targeted volume.
关键词： resting-state functional connectivity,seizure freedom,treatment-resistant epilepsy,MR-guided laser ablation,prefrontal cortices
更新于2025-09-12 10:27:22