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Articles 91 - 120 of 137

Full-Text Articles in Neurology

Stochastic Modeling Of Radiation-Induced Dendritic Damage On In Silico Mouse Hippocampal Neurons, Eliedonna Cacao, Vipan K. Parihar, Charles L. Limoli, Francis A. Cucinotta Apr 2018

Stochastic Modeling Of Radiation-Induced Dendritic Damage On In Silico Mouse Hippocampal Neurons, Eliedonna Cacao, Vipan K. Parihar, Charles L. Limoli, Francis A. Cucinotta

Health Physics and Diagnostic Sciences Faculty Research

Cognitive dysfunction associated with radiotherapy for cancer treatment has been correlated to several factors, one of which is changes to the dendritic morphology of neuronal cells. Alterations in dendritic geometry and branching patterns are often accompanied by deficits that impact learning and memory. The purpose of this study is to develop a novel predictive model of neuronal dendritic damages caused by exposure to low linear energy transfer (LET) radiation, such as X-rays, gamma-rays and high-energy protons. We established in silico representations of mouse hippocampal dentate granule cell layer (GCL) and CA1 pyramidal neurons, which are frequently examined in radiation-induced cognitive …


Electrophysiological Signatures Of Spatial Boundaries In The Human Subiculum., Sang Ah Lee, Jonathan F. Miller, Andrew J. Watrous, Michael R. Sperling, Ashwini Sharan, Gregory A. Worrell, Brent M. Berry, Joshua P. Aronson, Kathryn A. Davis, Robert E. Gross, Bradley Lega, Sameer Sheth, Sandhitsu R. Das, Joel M. Stein, Richard Gorniak, Daniel S. Rizzuto, Joshua Jacobs Mar 2018

Electrophysiological Signatures Of Spatial Boundaries In The Human Subiculum., Sang Ah Lee, Jonathan F. Miller, Andrew J. Watrous, Michael R. Sperling, Ashwini Sharan, Gregory A. Worrell, Brent M. Berry, Joshua P. Aronson, Kathryn A. Davis, Robert E. Gross, Bradley Lega, Sameer Sheth, Sandhitsu R. Das, Joel M. Stein, Richard Gorniak, Daniel S. Rizzuto, Joshua Jacobs

Department of Radiology Faculty Papers

Environmental boundaries play a crucial role in spatial navigation and memory across a wide range of distantly related species. In rodents, boundary representations have been identified at the single-cell level in the subiculum and entorhinal cortex of the hippocampal formation. Although studies of hippocampal function and spatial behavior suggest that similar representations might exist in humans, boundary-related neural activity has not been identified electrophysiologically in humans until now. To address this gap in the literature, we analyzed intracranial recordings from the hippocampal formation of surgical epilepsy patients (of both sexes) while they performed a virtual spatial navigation task and compared …


Closed-Loop Stimulation Of Temporal Cortex Rescues Functional Networks And Improves Memory., Youssef Ezzyat, Paul A. Wanda, Deborah F. Levy, Allison Kadel, Ada Aka, Isaac Pedisich, Michael R. Sperling, Ashwini Sharan, Bradley C. Lega, Alexis Burks, Robert E. Gross, Cory S. Inman, Barbara C. Jobst, Mark A. Gorenstein, Kathryn A. Davis, Gregory A. Worrell, Michal T. Kucewicz, Joel M. Stein, Richard Gorniak, Sandhitsu R. Das, Daniel S. Rizzuto, Michael J. Kahana Feb 2018

Closed-Loop Stimulation Of Temporal Cortex Rescues Functional Networks And Improves Memory., Youssef Ezzyat, Paul A. Wanda, Deborah F. Levy, Allison Kadel, Ada Aka, Isaac Pedisich, Michael R. Sperling, Ashwini Sharan, Bradley C. Lega, Alexis Burks, Robert E. Gross, Cory S. Inman, Barbara C. Jobst, Mark A. Gorenstein, Kathryn A. Davis, Gregory A. Worrell, Michal T. Kucewicz, Joel M. Stein, Richard Gorniak, Sandhitsu R. Das, Daniel S. Rizzuto, Michael J. Kahana

Department of Neurology Faculty Papers

Memory failures are frustrating and often the result of ineffective encoding. One approach to improving memory outcomes is through direct modulation of brain activity with electrical stimulation. Previous efforts, however, have reported inconsistent effects when using open-loop stimulation and often target the hippocampus and medial temporal lobes. Here we use a closed-loop system to monitor and decode neural activity from direct brain recordings in humans. We apply targeted stimulation to lateral temporal cortex and report that this stimulation rescues periods of poor memory encoding. This system also improves later recall, revealing that the lateral temporal cortex is a reliable target …


Electrical Stimulation Modulates High Γ Activity And Human Memory Performance., Michal T. Kucewicz, Brent M. Berry, Vaclav Kremen, Laura R. Miller, Fatemeh Khadjevand, Youssef Ezzyat, Joel M. Stein, Paul Wanda, Michael R. Sperling, Richard Gorniak, Md, Kathryn A. Davis, Barbara C. Jobst, Robert E. Gross, Bradley Lega, S Matt Stead, Daniel S. Rizzuto, Michael J. Kahana, Gregory A, Worrell Feb 2018

Electrical Stimulation Modulates High Γ Activity And Human Memory Performance., Michal T. Kucewicz, Brent M. Berry, Vaclav Kremen, Laura R. Miller, Fatemeh Khadjevand, Youssef Ezzyat, Joel M. Stein, Paul Wanda, Michael R. Sperling, Richard Gorniak, Md, Kathryn A. Davis, Barbara C. Jobst, Robert E. Gross, Bradley Lega, S Matt Stead, Daniel S. Rizzuto, Michael J. Kahana, Gregory A, Worrell

Department of Neurology Faculty Papers

Direct electrical stimulation of the brain has emerged as a powerful treatment for multiple neurological diseases, and as a potential technique to enhance human cognition. Despite its application in a range of brain disorders, it remains unclear how stimulation of discrete brain areas affects memory performance and the underlying electrophysiological activities. Here, we investigated the effect of direct electrical stimulation in four brain regions known to support declarative memory: hippocampus (HP), parahippocampal region (PH) neocortex, prefrontal cortex (PF), and lateral temporal cortex (TC). Intracranial EEG recordings with stimulation were collected from 22 patients during performance of verbal memory tasks. We …


Mra-Based Evaluation Of Anatomical Variation Of Circle Of Willis In Adult Pakistanis, Rehana Shaikh, Saba Sohail Feb 2018

Mra-Based Evaluation Of Anatomical Variation Of Circle Of Willis In Adult Pakistanis, Rehana Shaikh, Saba Sohail

Department of Radiology

Objective: To determine the frequency and patterns of normal anatomical variation of Circle of Willis on magnetic resonance angiogram in adults without cerebrovascular disease.
Methods: This descriptive cross-sectional study was conducted at the Radiology Department of Dow University of Health Sciences / Civil Hospital, Karachi, from January to December 2016, and comprised patients referred for magnetic resonance imaging of the brain and magnetic resonance angiogram without any clinical or radiological manifestation of cerebrovascular disease, primarily including those with suspected demyelination, infection, epilepsy or metastases. Three-dimensional time-of-flight magnetic resonance angiography was performed. The Circle of Willis was assessed for its completeness …


Multiple System Atrophy - The Cerebellar Type With “Hot Cross Bun Sign” On Mri, Rehana Shaikh, Saba Sohail, Nasreen Naz Feb 2018

Multiple System Atrophy - The Cerebellar Type With “Hot Cross Bun Sign” On Mri, Rehana Shaikh, Saba Sohail, Nasreen Naz

Department of Radiology

Multiple system atrophy (MSA) is an adult onset, progressive, idiopathic neurodegenerative disease that clinically manifest as MSA-C with cerebellar signs predominant, MSA-P with Parkinsonian features predominant and MSA-A with autonomic signs and symptoms. MRI has an important role in its diagnosis with a characteristic finding described as "hot cross bun" sign seen in MSA of cerebellar type (MSA-C). We have seen two cases of MSA-C referred to Radiology Department, Civil Hospital Karachi in February 2017 and March 2017 who presented with difficulty in walking and speech and foecal and urinary incontinence. The MRI showed atrophy of pons, cerebellum and middle …


Intra-Arterial Nitroglycerin As Directed Acute Treatment In Experimental Ischemic Stroke, Michael E. Maniskas, Jill M. Roberts, Rebecca Trueman, Annastazia E. Learoyd, Amanda A. Gorman, Justin F. Fraser, Gregory J. Bix Jan 2018

Intra-Arterial Nitroglycerin As Directed Acute Treatment In Experimental Ischemic Stroke, Michael E. Maniskas, Jill M. Roberts, Rebecca Trueman, Annastazia E. Learoyd, Amanda A. Gorman, Justin F. Fraser, Gregory J. Bix

Neuroscience Faculty Publications

BACKGROUND: Nitroglycerin (also known as glyceryl trinitrate (GTN)), a vasodilator best known for treatment of ischemic heart disease, has also been investigated for its potential therapeutic benefit in ischemic stroke. The completed Efficacy of Nitric Oxide in Stroke trial suggested that GTN has therapeutic benefit with acute (within 6 hours) transdermal systemic sustained release therapy.

OBJECTIVE: To examine an alternative use of GTN as an acute therapy for ischemic stroke following successful recanalization.

METHODS: We administered GTN IA following transient middle cerebral artery occlusion in mice. Because no standard dose of GTN is available following emergent large vessel occlusion, we …


Silent Sentence Completion Shows Superiority Localizing Wernicke's Area And Activation Patterns Of Distinct Language Paradigms Correlate With Genomics: Prospective Study., Kamel El Salek, Islam S. Hassan, Aikaterini Kotrotsou, Srishti Abrol, Scott H. Faro, Feroze B. Mohamed, Pascal O. Zinn, Wei Wei, Nan Li, Ashok J. Kumar, Jeffrey S. Weinberg, Jeffrey S. Wefel, Shelli R. Kesler, Ho-Ling Anthony Liu, Ping Hou, R. Jason Stafford, Sujit Prabhu, Raymond Sawaya, Rivka R. Colen Dec 2017

Silent Sentence Completion Shows Superiority Localizing Wernicke's Area And Activation Patterns Of Distinct Language Paradigms Correlate With Genomics: Prospective Study., Kamel El Salek, Islam S. Hassan, Aikaterini Kotrotsou, Srishti Abrol, Scott H. Faro, Feroze B. Mohamed, Pascal O. Zinn, Wei Wei, Nan Li, Ashok J. Kumar, Jeffrey S. Weinberg, Jeffrey S. Wefel, Shelli R. Kesler, Ho-Ling Anthony Liu, Ping Hou, R. Jason Stafford, Sujit Prabhu, Raymond Sawaya, Rivka R. Colen

Department of Radiology Faculty Papers

Preoperative mapping of language areas using fMRI greatly depends on the paradigms used, as different tasks harness distinct capabilities to activate speech processing areas. In this study, we compared the ability of 3 covert speech paradigms: Silent Sentence Completion (SSC), category naming (CAT) and verbal fluency (FAS), in localizing the Wernicke's area and studied the association between genomic markers and functional activation. Fifteen right-handed healthy volunteers and 35 mixed-handed patients were included. We focused on the anatomical areas of posterosuperior, middle temporal and angular gyri corresponding to Wernicke's area. Activity was deemed significant in a region of interest if P < 0.05. Association between fMRI activation and genomic mutation status was obtained. Results demonstrated SSC's superiority at localizing Wernicke's area. SSC demonstrated functional activity in 100% of cancer patients and healthy volunteers; which was significantly higher than those for FAS and CAT. Patients with 1p/19q non-co-deleted had higher extent of activation on SSC (P < 0.02). Those with IDH-1 wild-type were more likely to show no activity on CAT (P < 0.05). SSC is a robust paradigm for localizing Wernicke's area, making it an important clinical tool for function-preserving surgeries. We also found a correlation between tumor genomics and functional activation, which deserves more comprehensive study.


Bimodal Coupling Of Ripples And Slower Oscillations During Sleep In Patients With Focal Epilepsy., Inkyung Song, Iren Orosz, Inna Chervoneva, Zachary J. Waldman, Itzhak Fried, Chengyuan Wu, Ashwini Sharan, Noriko Salamon, Richard Gorniak, Sandra Dewar, Anatol Bragin, Jerome Engel, Michael R. Sperling, Richard Staba, Shennan A. Weiss Nov 2017

Bimodal Coupling Of Ripples And Slower Oscillations During Sleep In Patients With Focal Epilepsy., Inkyung Song, Iren Orosz, Inna Chervoneva, Zachary J. Waldman, Itzhak Fried, Chengyuan Wu, Ashwini Sharan, Noriko Salamon, Richard Gorniak, Sandra Dewar, Anatol Bragin, Jerome Engel, Michael R. Sperling, Richard Staba, Shennan A. Weiss

Department of Neurology Faculty Papers

OBJECTIVE: Differentiating pathologic and physiologic high-frequency oscillations (HFOs) is challenging. In patients with focal epilepsy, HFOs occur during the transitional periods between the up and down state of slow waves. The preferred phase angles of this form of phase-event amplitude coupling are bimodally distributed, and the ripples (80-150 Hz) that occur during the up-down transition more often occur in the seizure-onset zone (SOZ). We investigated if bimodal ripple coupling was also evident for faster sleep oscillations, and could identify the SOZ.

METHODS: Using an automated ripple detector, we identified ripple events in 40-60 min intracranial electroencephalography (iEEG) recordings from 23 …


Video Microscope Robotic Arm-Assisted, Neuronavigation-Guided Glioma Resection And Regional Sampling, Muhammad Waqas, Ather Enam, Fauzan A Hashmi, Fatima Mubarak, Fazal Arain Oct 2017

Video Microscope Robotic Arm-Assisted, Neuronavigation-Guided Glioma Resection And Regional Sampling, Muhammad Waqas, Ather Enam, Fauzan A Hashmi, Fatima Mubarak, Fazal Arain

Section of Neurosurgery

High-grade gliomas possess internal pathological heterogeneity. Selective sampling of different tumor regions can help in the study of this heterogeneity. In this report, we have described the use of a novel navigation and optical system for the selective regional sampling of a high-grade glioma lesion. A 45-year-old gentleman presented to us with complaints of intermittent frontal headaches for past eight months. On examination, he had subtle pyramidal weakness in left upper and lower extremities. Magnetic resonance imaging (MRI) showed a large contrast-enhancing, space-occupying lesion in the right frontal lobe causing perilesional edema and midline shift. We marked four different regions …


Diffusion Tensor Imaging For Ruptured Cerebral Arteriovenous Malformation, Muhammad Waqas, Ayesha Siddiqui, Fatima Mubarak, Ather Enam Sep 2017

Diffusion Tensor Imaging For Ruptured Cerebral Arteriovenous Malformation, Muhammad Waqas, Ayesha Siddiqui, Fatima Mubarak, Ather Enam

Section of Neurosurgery

Non-ruptured arteriovenous malformations (AVMs) rarely cause tract disruption. Few studies have described how ruptured AVMs influence white matter (WM) tract morphology. We reviewed consecutive AVM cases treated at a tertiary care hospital where diffusion tensor imaging (DTI) tractography was obtained preoperatively. DTI was performed using the Synaptive Plan (Synaptive Medical Inc., Toronto, Canada). Quality control was performed by clinical application specialist. Perinidal fractional anisotropy (FA) value of corticospinal tracts (CST) was obtained. A reference FA value was obtained from the corresponding area on the contralateral side. Images were evaluated by a consultant neuroradiologist. Radiological findings were correlated with clinical findings. …


A Clinical Practice Guideline For The Management Of Patients With Acute Spinal Cord Injury: Recommendations On The Role Of Baseline Magnetic Resonance Imaging In Clinical Decision Making And Outcome Prediction, Michael G. Fehlings, Allan R. Martin, Lindsay A. Tetreault, Bizhan Aarabi, Paul Anderson, Paul M. Arnold, Darrel Brodke, Anthony S. Burns, Kazuhiro Chiba, Joseph R. Dettori, Julio C. Furlan, Gregory Hawryluk, Langston T. Holly, Susan Howley, Tara Jeji, Sukhvinder Kalsi-Ryan, Mark Kotter, Shekar Kurpad, Brian K. Kwon, Ralph J. Marino, Eric Massicotte, Geno J. Merli, James W. Middleton, Hiroaki Nakashima, Narihito Nagoshi, Katherine Palmieri, Anoushka Singh, Andrea C. Skelly, Eve C. Tsai, Alexander R. Vaccaro, Jefferson R. Wilson, Albert Yee, James Harrop Sep 2017

A Clinical Practice Guideline For The Management Of Patients With Acute Spinal Cord Injury: Recommendations On The Role Of Baseline Magnetic Resonance Imaging In Clinical Decision Making And Outcome Prediction, Michael G. Fehlings, Allan R. Martin, Lindsay A. Tetreault, Bizhan Aarabi, Paul Anderson, Paul M. Arnold, Darrel Brodke, Anthony S. Burns, Kazuhiro Chiba, Joseph R. Dettori, Julio C. Furlan, Gregory Hawryluk, Langston T. Holly, Susan Howley, Tara Jeji, Sukhvinder Kalsi-Ryan, Mark Kotter, Shekar Kurpad, Brian K. Kwon, Ralph J. Marino, Eric Massicotte, Geno J. Merli, James W. Middleton, Hiroaki Nakashima, Narihito Nagoshi, Katherine Palmieri, Anoushka Singh, Andrea C. Skelly, Eve C. Tsai, Alexander R. Vaccaro, Jefferson R. Wilson, Albert Yee, James Harrop

Department of Rehabilitation Medicine Faculty Papers

Introduction: The objective of this guideline is to outline the role of magnetic resonance imaging (MRI) in clinical decision making and outcome prediction in patients with traumatic spinal cord injury (SCI). Methods: A systematic review of the literature was conducted to address key questions related to the use of MRI in patients with traumatic SCI. This review focused on longitudinal studies that controlled for baseline neurologic status. A multidisciplinary Guideline Development Group (GDG) used this information, their clinical expertise, and patient input to develop recommendations on the use of MRI for SCI patients. Based on GRADE (Grading of Recommendation, Assessment, …


Debate On Human Aging And Lifespan, Mohammad Rafi, Abass Alavi Aug 2017

Debate On Human Aging And Lifespan, Mohammad Rafi, Abass Alavi

Department of Neurology Faculty Papers

The issue of human lifespan has long been a matter of controversy among scientists. In spite of the recent claim by Dong et al that human lifespan is limited to 115 years, with the mounting improvements in biotechnology and scientific understanding of aging, we may be confident that aging will slow down over the course of the current century extending human longevity much longer than 115 years.


Cascaded Multi-View Canonical Correlation (Camcco) For Early Diagnosis Of Alzheimer's Disease Via Fusion Of Clinical, Imaging And Omic Features, Asha Singanamalli, Haibo Wang, Anant Madabhushi, Michael Weiner, Paul Aisen, Ronald Petersen, Clifford Jack, William Jagust, John Trojanowki, Arthur Toga, Laurel Beckett, Robert Green, Andrew Saykin, John Morris, Leslie Shaw, Jeffrey Kaye, Joseph Quinn, Lisa Silbert, Betty Lind, Raina Carter, Sara Dolen, Lon Schneider, Sonia Pawluczyk, Mauricio Beccera, Liberty Teodoro, Bryan Spann, James Brewer, Helen Vanderswag, Adam Fleisher, Judith Heidebrink, Charles Smith, Greg A. Jicha, Peter A. Hardy, Partha Sinha, Elizabeth Oates, Gary Conrad Aug 2017

Cascaded Multi-View Canonical Correlation (Camcco) For Early Diagnosis Of Alzheimer's Disease Via Fusion Of Clinical, Imaging And Omic Features, Asha Singanamalli, Haibo Wang, Anant Madabhushi, Michael Weiner, Paul Aisen, Ronald Petersen, Clifford Jack, William Jagust, John Trojanowki, Arthur Toga, Laurel Beckett, Robert Green, Andrew Saykin, John Morris, Leslie Shaw, Jeffrey Kaye, Joseph Quinn, Lisa Silbert, Betty Lind, Raina Carter, Sara Dolen, Lon Schneider, Sonia Pawluczyk, Mauricio Beccera, Liberty Teodoro, Bryan Spann, James Brewer, Helen Vanderswag, Adam Fleisher, Judith Heidebrink, Charles Smith, Greg A. Jicha, Peter A. Hardy, Partha Sinha, Elizabeth Oates, Gary Conrad

Neurology Faculty Publications

The introduction of mild cognitive impairment (MCI) as a diagnostic category adds to the challenges of diagnosing Alzheimer's Disease (AD). No single marker has been proven to accurately categorize patients into their respective diagnostic groups. Thus, previous studies have attempted to develop fused predictors of AD and MCI. These studies have two main limitations. Most do not simultaneously consider all diagnostic categories and provide suboptimal fused representations using the same set of modalities for prediction of all classes. In this work, we present a combined framework, cascaded multiview canonical correlation (CaMCCo), for fusion and cascaded classification that incorporates all diagnostic …


Mr Imaging Findings In Xp21.2 Duplication Syndrome, Matthew T. Whitehead, Guy Helman, Andrea L. Gropman May 2016

Mr Imaging Findings In Xp21.2 Duplication Syndrome, Matthew T. Whitehead, Guy Helman, Andrea L. Gropman

Radiology Faculty Publications

Xp21.2 duplication syndrome is a rare genetic disorder of undetermined prevalence and clinical relevance. As the use of chromosomal microarray has become first line for the work-up of childhood developmental delay, more gene deletions and duplications have been recognized. To the best of our knowledge, the imaging findings of Xp21.2 duplication syndrome have not been reported. We report a case of a 33 month-old male referred for developmental delay that was found to have an Xp21.2 duplication containing IL1RAPL1 and multiple midline brain malformations.


The Connectivity Domain: Analyzing Resting State Fmri Data Using Feature-Based Data-Driven And Model-Based Methods, Armin Iraji, Vince D. Calhoun, Natalie M. Wiseman, Esmaeil Davoodi-Bojd, Mohammad R. N. Avanaki, Zhifeng Kou Apr 2016

The Connectivity Domain: Analyzing Resting State Fmri Data Using Feature-Based Data-Driven And Model-Based Methods, Armin Iraji, Vince D. Calhoun, Natalie M. Wiseman, Esmaeil Davoodi-Bojd, Mohammad R. N. Avanaki, Zhifeng Kou

Biomedical Engineering Faculty Research Publications

Spontaneous fluctuations of resting state functional MRI (rsfMRI) have been widely used to understand the macro-connectome of the human brain. However, these fluctuations are not synchronized among subjects, which leads to limitations and makes utilization of first-level model-based methods challenging. Considering this limitation of rsfMRI data in the time domain, we propose to transfer the spatiotemporal information of the rsfMRI data to another domain, the connectivity domain, in which each value represents the same effect across subjects. Using a set of seed networks and a connectivity index to calculate the functional connectivity for each seed network, we transform data into …


Peripheral (Deep) But Not Periventricular Mri White Matter Hyperintensities Are Increased In Clinical Vascular Dementia Compared To Alzheimer's Disease, Charles D. Smith, Eleanor S. Johnson, Linda J. Van Eldik, Gregory A. Jicha, Frederick A. Schmitt, Peter T. Nelson, Richard J. Kryscio, Richard R. Murphy, Clinton V. Wellnitz Mar 2016

Peripheral (Deep) But Not Periventricular Mri White Matter Hyperintensities Are Increased In Clinical Vascular Dementia Compared To Alzheimer's Disease, Charles D. Smith, Eleanor S. Johnson, Linda J. Van Eldik, Gregory A. Jicha, Frederick A. Schmitt, Peter T. Nelson, Richard J. Kryscio, Richard R. Murphy, Clinton V. Wellnitz

Neurology Faculty Publications

Background and purpose: Vascular dementia (VAD) is a complex diagnosis at times difficult to distinguish from Alzheimer's disease (AD). MRI scans often show white matter hyperintensities (WMH) in both conditions. WMH increase with age, and both VAD and AD are associated with aging, thus presenting an attribution conundrum. In this study, we sought to show whether the amount of WMH in deep white matter (dWMH), versus periventricular white matter (PVH), would aid in the distinction between VAD and AD, independent of age. Methods: Blinded semiquantitative ratings of WMH validated by objective quantitation of WMH volume from standardized MRI image acquisitions. …


Mri Signal Intensity Differentiation Of Brainstem Encephalitis Induced By Enterovirus 71: A Classification Approach For Acute And Convalescence Stages, Hongwu Zeng, Wenxian Huang, Feiqiu Wen, Yonker Wang, Yungen Gan, Weibin Zeng, Ranran Chen, Yanxia He, Zaiyi Liu, Changhong Liang, Kelvin K. L. Wong Feb 2016

Mri Signal Intensity Differentiation Of Brainstem Encephalitis Induced By Enterovirus 71: A Classification Approach For Acute And Convalescence Stages, Hongwu Zeng, Wenxian Huang, Feiqiu Wen, Yonker Wang, Yungen Gan, Weibin Zeng, Ranran Chen, Yanxia He, Zaiyi Liu, Changhong Liang, Kelvin K. L. Wong

Radiology Faculty Publications

Background: The objective of this study is to assess standardized histograms of signal intensities of T1 signal and T2 signal on sagittal view without enhancement during (1) acute stage, and (2) convalescence stage of pediatric patients with Enterovirus 71 related brainstem encephalitis (BE), and with respect to (3) healthy normal.

Methods: Our subjects were hospitalized between March 2010 and October 2012, and underwent pre- and post-contrast MRI studies. The research question to be answered is whether the comparison of the MRI image intensity histograms and relevant statistical quantification can add new knowledge to the diagnosis of BE patients. So, both …


Radioresistance Of Brain Tumors, K. Kelley, J. Knisely, M. Symons, R. Ruggieri Jan 2016

Radioresistance Of Brain Tumors, K. Kelley, J. Knisely, M. Symons, R. Ruggieri

Journal Articles

Radiation therapy (RT) is frequently used as part of the standard of care treatment of the majority of brain tumors. The efficacy of RT is limited by radioresistance and by normal tissue radiation tolerance. This is highlighted in pediatric brain tumors where the use of radiation is limited by the excessive toxicity to the developing brain. For these reasons, radiosensitization of tumor cells would be beneficial. In this review, we focus on radioresistance mechanisms intrinsic to tumor cells. We also evaluate existing approaches to induce radiosensitization and explore future avenues of investigation.


Pediatric Neuroradiology Pre-Call Primer, Trevor Morrison, Gilbert Vezina, Nadja Kadom Nov 2015

Pediatric Neuroradiology Pre-Call Primer, Trevor Morrison, Gilbert Vezina, Nadja Kadom

E-Learning Modules

Pediatric neuroimaging can provide a challenge to radiology residents during call due to the fact that it is infrequently encountered in many institutions. The goal of this teaching tool is to provide radiology residents with background knowledge in pediatric brain anatomy and pathology in preparation for taking call. There is one teaching tool and one assessment tool with answers, all three of which are in PowerPoint format. Emergency neuroradiology topics discussed in this module are sutures, skull fractures, bleeds, sulci and mass effect, cisterns, and herniations. After implementing this teaching tool at our institution with all incoming residents and fellows, …


Magnetic Resonance Spectroscopy Of Enhancing Cerebral Lesions: Analysis Of 78 Histopathology Proven Cases, Muhammad Shahbaz Alam, Humera Ahsan, Zafar Sajjad, Madiha Beg, Umer Bhatti, Ather Enam, Mohammad Wasay Oct 2014

Magnetic Resonance Spectroscopy Of Enhancing Cerebral Lesions: Analysis Of 78 Histopathology Proven Cases, Muhammad Shahbaz Alam, Humera Ahsan, Zafar Sajjad, Madiha Beg, Umer Bhatti, Ather Enam, Mohammad Wasay

Department of Radiology

Objectives: To investigate the efficacy of magnetic resonance spectroscopy in differentiating various types of neoplastic and non-neoplastic enhancing cerebral lesions.
Methods: The prospective study was conducted from January 2007 to December 2009 at the Department of Radiology, Aga Khan University Hospital, Karachi. All patients with enhancing brain lesions on magnetic resonance imaging who underwent magnetic resonance spectroscopy and a biopsy with histopathological analysis were included in study. The lesions were categorised into neoplastic and non-neoplastic lesions on the basis of spectroscopy findings. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of magnetic resonance spectroscopy were calculated. …


Utilizing Fast Spin Echo Mri To Reduce Image Artifacts And Improve Implant/Tissue Interface Detection In Refractory Parkinson’S Patients With Deep Brain Stimulators, Subhendra N. Sarkar, Pooja R. Sarkar, Efstathios Papavassiliou, Rafael Rojas Feb 2014

Utilizing Fast Spin Echo Mri To Reduce Image Artifacts And Improve Implant/Tissue Interface Detection In Refractory Parkinson’S Patients With Deep Brain Stimulators, Subhendra N. Sarkar, Pooja R. Sarkar, Efstathios Papavassiliou, Rafael Rojas

Publications and Research

Introduction. In medically refractory Parkinson’s disease (PD) deep-brain stimulation (DBS) is an effective therapeutic tool. Postimplantation MRI is important in assessing tissue damage and DBS lead placement accuracy. We wanted to identify which MRI sequence can detectDBS leads with smallest artifactual signal void, allowing better tissue/electrode edge conspicuity.

Methods. Using an IRB approved protocol 8 advanced PDpatientswere imagedwithinMRconditional safety guidelines at lowRF power (SAR ≤ 0.1 W/kg) in coronal plane at 1.5T by various sequences.The image slices were subjectively evaluated for diagnostic quality and the lead contact diameters were compared to identify a sequence least affected by metallic leads.

Results …


Internal Maxillary Artery-Middle Cerebral Artery Bypass: Infratemporal Approach For Subcranial-Intracranial (Sc-Ic) Bypass, E. Nossek, P. Costantino, M. Eisenberg, A. R. Dehdashti, A. Setton, D. J. Chalif, R. A. Ortiz, D. J. Langer Jan 2014

Internal Maxillary Artery-Middle Cerebral Artery Bypass: Infratemporal Approach For Subcranial-Intracranial (Sc-Ic) Bypass, E. Nossek, P. Costantino, M. Eisenberg, A. R. Dehdashti, A. Setton, D. J. Chalif, R. A. Ortiz, D. J. Langer

Journal Articles

BACKGROUND:Internal maxillary artery (IMax)-middle cerebral artery (MCA) bypass has been recently described as an alternative to cervical extracranial-intracranial bypass. This technique uses a keyhole craniectomy in the temporal fossa that requires a technically challenging end-to-side anastomosis.OBJECTIVE:To describe a lateral subtemporal craniectomy of the middle cranial fossa floor to facilitate wide exposure of the IMax to facilitate bypass.METHODS:Orbitozygomatic osteotomy is used followed by frontotemporal craniotomy and subsequently laterotemporal fossa craniectomy, reaching its medial border at a virtual line connecting the foramen rotundum and foramen ovale. The IMax was identified by using established anatomic landmarks, neuronavigation, and micro Doppler probe (Mizuho Inc. …


Three‐Dimensional Brain Mri For Dbs Patients Within Ultra‐Low Radiofrequency Power Limits, Subhendra N. Sarkar, Efstathios Papavassiliou, David Hackney, David Alsop, Ananth Madhuranthakam, Ludy Shih, Reed Busse, Susan Laruche, Rafeeque Bhadelia Jan 2014

Three‐Dimensional Brain Mri For Dbs Patients Within Ultra‐Low Radiofrequency Power Limits, Subhendra N. Sarkar, Efstathios Papavassiliou, David Hackney, David Alsop, Ananth Madhuranthakam, Ludy Shih, Reed Busse, Susan Laruche, Rafeeque Bhadelia

Publications and Research

Background: For patients with deep brain stimulators (DBS), local absorbed radiofrequency (RF) power is unknown and is much higher than what the system estimates. We developed a comprehensive, highquality brain magnetic resonance imaging (MRI) protocol for DBS patients utilizing three-dimensional (3D) magnetic resonance sequences at very low RF power. Methods: Six patients with DBS were imaged (10 sessions) using a transmit/receive head coil at 1.5 Tesla with modified 3D sequences within ultra-low specific absorption rate (SAR) limits (0.1 W/kg) using T2, fast fluid-attenuated inversion recovery (FLAIR) and T1- weighted image contrast. Tissue signal and tissue contrast from the low-SAR images …


A Descriptive Study To Find Possible Correlation Between Mri Findings Of Pituitary Gland And Serum Prolactin Level, Muhammad Azeemuddin, Rohana Naqi, Mohammad Wasay Jun 2013

A Descriptive Study To Find Possible Correlation Between Mri Findings Of Pituitary Gland And Serum Prolactin Level, Muhammad Azeemuddin, Rohana Naqi, Mohammad Wasay

Department of Medicine

Objective: To explore equation, if any, between findings of magnetic resonance imaging of pituitary gland and serum prolactin level.

Methods: The retrospective, descriptive study was conducted at the Department of Radiology, Aga Khan University Hospital, Karachi, and related to patients\' records from April 19, 2006 to April 23, 2009. Seventy patients underwent magnetic resonance imaging of brain for pituitary gland. Inclusion criteria were all patients referred with relevant clinical symptoms or deranged serum prolactin level. Patients who were claustrophobic or had a pacemaker, aneurysm clip, metallic foreign body in the orbit or with no laboratory investigation were excluded from the …


Anatomical Relationships Of The Anterior Blood Vessels To The Lower Lumbar Intervertebral Discs: Analysis Based On Magnetic Resonance Imaging Of Patients In The Prone Position., Alexander R Vaccaro, Christopher K Kepler, Jeffrey A Rihn, Hidekazu Suzuki, John K Ratliff, James S Harrop, William B Morrison, Worawat Limthongkul, Todd J Albert Jun 2012

Anatomical Relationships Of The Anterior Blood Vessels To The Lower Lumbar Intervertebral Discs: Analysis Based On Magnetic Resonance Imaging Of Patients In The Prone Position., Alexander R Vaccaro, Christopher K Kepler, Jeffrey A Rihn, Hidekazu Suzuki, John K Ratliff, James S Harrop, William B Morrison, Worawat Limthongkul, Todd J Albert

Rothman Institute Papers

BACKGROUND: Intra-abdominal vascular injuries are rare during posterior lumbar spinal surgery, but they can result in major morbidity or mortality when they do occur. We are aware of no prior studies that have used prone patient positioning during magnetic resonance imaging for the purpose of characterizing the retroperitoneal iliac vasculature with respect to the intervertebral disc. The purpose of this study was to define the vascular anatomy adjacent to the lower lumbar spine with use of supine and prone magnetic resonance imaging.

METHODS: A prospective observational study included thirty patients without spinal abnormality who underwent supine and prone magnetic resonance …


Segmentation Of Corpus Callosum Using Diffusion Tensor Imaging: Validation In Patients With Glioblastoma, Mohammad-Reza Nazem-Zadeh, Sona Saksena, Abbas Babajani-Fermi, Quan Jiang, Hamid Soltanian-Zadeh, Mark Rosenblum, Tom Mikkelsen, Rajan Jain Jan 2012

Segmentation Of Corpus Callosum Using Diffusion Tensor Imaging: Validation In Patients With Glioblastoma, Mohammad-Reza Nazem-Zadeh, Sona Saksena, Abbas Babajani-Fermi, Quan Jiang, Hamid Soltanian-Zadeh, Mark Rosenblum, Tom Mikkelsen, Rajan Jain

Wayne State University Associated BioMed Central Scholarship

Abstract

Background

This paper presents a three-dimensional (3D) method for segmenting corpus callosum in normal subjects and brain cancer patients with glioblastoma.

Methods

Nineteen patients with histologically confirmed treatment naïve glioblastoma and eleven normal control subjects underwent DTI on a 3T scanner. Based on the information inherent in diffusion tensors, a similarity measure was proposed and used in the proposed algorithm. In this algorithm, diffusion pattern of corpus callosum was used as prior information. Subsequently, corpus callosum was automatically divided into Witelson subdivisions. We simulated the potential rotation of corpus callosum under tumor pressure and studied the reproducibility of the …


Infectious Intracranial Aneurysms: Collaboration For Treatment Success, Erin M. Conahan Rn, Bsn, Cnrn Jan 2012

Infectious Intracranial Aneurysms: Collaboration For Treatment Success, Erin M. Conahan Rn, Bsn, Cnrn

Patient Care Services / Nursing

No abstract provided.


Endovascular Approach As Primary Treatment For Traumatic Carotid Cavernous Fistula: Local Experience From Pakistan, Rana Shoaib Hamid, Tanveer Ul Haq, Muhammad Shahzad Shamim, Syed Faraz Kazim, Basit Salam Oct 2011

Endovascular Approach As Primary Treatment For Traumatic Carotid Cavernous Fistula: Local Experience From Pakistan, Rana Shoaib Hamid, Tanveer Ul Haq, Muhammad Shahzad Shamim, Syed Faraz Kazim, Basit Salam

Department of Radiology

Objective: To evaluate the technical success, complications and outcome of endovascular management of post traumatic carotid cavernous fistula (CCF) in patients presenting at a tertiary care hospital in Karahci.
Methods: Descriptive case series of 26 patients of post traumatic CCF treated by endovascular techniques was carried out at Radiology and Neurosurgery departments of Aga Khan University hospital between January 2010 to March 2010. Medical records and radiology reports were retrospectively reviewed from November 2000 to December 2009. The diagnosis was primarily clinical and was confirmed in all cases by CT or MRI. Endovascular procedures were performed under general anaesthesia through …


Brain Activation And Connectivity In Non-Disabled Multiple Sclerosis Patients, Rene A. Colorado Aug 2011

Brain Activation And Connectivity In Non-Disabled Multiple Sclerosis Patients, Rene A. Colorado

Dissertations and Theses (Open Access)

Multiple sclerosis (MS) is the most common demyelinating disease affecting the central nervous system. There is no cure for MS and current therapies have limited efficacy. While the majority of individuals with MS develop significant clinical disability, a subset experiences a disease course with minimal impairment even in the presence of significant apparent tissue damage on magnetic resonance imaging (MRI). The current studies combined functional MRI and diffusion tensor imaging (DTI) to elucidate brain mechanisms associated with lack of clinical disability in patients with MS. Recent evidence has implicated cortical reorganization as a mechanism to limit the clinical manifestation of …