Publications by authors named "Niogi S"

Magnetic resonance imaging (MRI) has emerged as a promising technique for non-invasive medical imaging. The primary challenge in MRI is the trade-off between image visual quality and acquisition time. Current MRI image denoising algorithms employ global thresholding to denoise the whole image, which leads to inadequate denoising or image distortion.

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Background And Purpose: Traumatic brain injury (TBI) is a major source of health loss and disability worldwide. Accurate and timely diagnosis of TBI is critical for appropriate treatment and management of the condition. Neuroimaging plays a crucial role in the diagnosis and characterization of TBI.

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Article Synopsis
  • - The study investigates the role of microglia in the brainstem related to Alzheimer's disease (AD) using TSPO PET imaging, focusing particularly on the inferior colliculi (IC) due to its potential link to auditory dysfunction.
  • - Results indicated that TSPO expression in the IC decreases with age and in AD patients, contrasting with increased TSPO expression in the cortex with aging and AD, suggesting different roles for microglia in these regions.
  • - The findings emphasize the need for further research on brainstem microglia, as their activation in the IC might serve a protective function, highlighting regional differences in the pathology of AD.
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Objective: Minimally invasive endoscope-assisted approaches to the anterior skull base offer an alternative to traditional open craniotomies. Given the restrictive operative corridor, appropriate case selection is critical for success. In this paper, the authors present the results of three different minimal access approaches to meningiomas of the anterior and middle fossae and examine the differences in the target areas considered appropriate for each approach, as well as the outcomes, to determine whether the surgical goals were achieved.

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Clinical adoption of an artificial intelligence-enabled imaging tool requires critical appraisal of its life cycle from development to implementation by using a systematic, standardized, and objective approach that can verify both its technical and clinical efficacy. Toward this concerted effort, the ASFNR/ASNR Artificial Intelligence Workshop Technology Working Group is proposing a hierarchal evaluation system based on the quality, type, and amount of scientific evidence that the artificial intelligence-enabled tool can demonstrate for each component of its life cycle. The current proposal is modeled after the levels of evidence in medicine, with the uppermost level of the hierarchy showing the strongest evidence for potential impact on patient care and health care outcomes.

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Objective: The aim of this study was to determine if the distinction between planum sphenoidale (PS) and tuberculum sellae (TS) meningiomas is clinically meaningful and impacts the results of the endoscopic endonasal approach (EEA).

Methods: A consecutive series of patients who were 18 years of age or older and underwent EEA for newly diagnosed grade I PS meningiomas (PSMs) and TS meningiomas (TSMs) between October 2007 and May 2021 were included. The PS and TS were distinguished by drawing a line passing through the center of the TS and perpendicular to the PS on postcontrast T1-weighted MRI.

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Repeated mild Traumatic Brain Injury (TBI) is a risk factor for Chronic Traumatic Encephalopathy (CTE), characterized pathologically by neurofibrillary tau deposition in the depths of brain sulci and surrounding blood vessels. The mechanism by which TBI leads to CTE remains unknown but has been posited to relate to axonal shear injury leading to release and possibly deposition of tau at the time of injury. As part of an IRB-approved study designed to learn how processes occurring acutely after TBI may predict later proteinopathy and neurodegeneration, we performed tau PET using 18F-MK6240 and MRI within 14 days of complicated mild TBI in three subjects.

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The visual system is known to be vital for cognition and perception in the feline and canine and much behavioral research for these species has used visual stimuli and focused on visual perception. There has been extensive investigations into the visual pathway in cats and dogs via histological and neurobiological methods, however to date, only one study has mapped the canine optic pathway in vivo. Advanced imaging methods such as diffusion MRI (DTI) have been routinely used in human research to study the visual system in vivo.

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Background And Purpose: Cerebral adrenoleukodystrophy is a devastating neurological disorder caused by mutations in the gene. Our aim was to model and compare the growth of early cerebral lesions from longitudinal MRIs obtained in presymptomatic patients with progressive and arrested cerebral adrenoleukodystrophy using quantitative MR imaging-based lesion volumetry.

Materials And Methods: We retrospectively quantified and modeled the longitudinal growth of early cerebral lesions from 174 MRIs obtained from 36 presymptomatic male patients with cerebral adrenoleukodystrophy.

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White matter dysfunction and degeneration have been a topic of great interest in healthy and pathological aging. While ex vivo studies have investigated age-related changes in canines, little in vivo canine aging research exists. Quantitative diffusion MRI such as diffusion tensor imaging (DTI) has demonstrated aging and neurodegenerative white matter changes in humans.

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Traumatic brain injury (TBI) is a major cause of morbidity and mortality in children; survivors experience long-term cognitive and motor deficits. To date, studies predicting outcome following pediatric TBI have primarily focused on acute behavioral responses and proxy measures of injury severity; unsurprisingly, these measures explain very little of the variance following heterogenous injury. In adults, certain acute imaging biomarkers help predict cognitive and motor recovery following moderate to severe TBI.

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Head trauma is a frequent indication for cranial imaging in children. The majority of accidental pediatric head trauma is minor and sustained without intracranial injury. Well-validated pediatric-specific clinical decision guidelines should be used to identify very low-risk children who can safely forgo imaging.

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While the diagnosis of traumatic brain injury (TBI) is a clinical decision, neuroimaging remains vital for guiding management on the basis of identification of intracranial pathologic conditions. CT is the mainstay of imaging of acute TBI for both initial triage and follow-up, as it is fast and accurate in detecting both primary and secondary injuries that require neurosurgical intervention. MRI is more sensitive for the detection of certain intracranial injuries (eg, axonal injuries) and blood products 24-48 hours after injury, but it has limitations (eg, speed, accessibility, sensitivity to motion, and cost).

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Objective: Statistical challenges exist when using diffusion tensor imaging (DTI) to assess traumatic axonal injury (TAI) in individual concussed athletes. The authors examined active professional American football players over a 6-year time period to study potential TAI after concussion and assess optimal methods to analyze DTI at the individual level.

Methods: Active American professional football players recruited prospectively were assessed with DTI, conventional MRI, and standard clinical workup.

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Objective: The authors tested the feasibility of magnetic resonance-guided focused ultrasound (MRgFUS) ablation of mesial temporal lobe epilepsy (MTLE) seizure circuits. Up to one-third of patients with mesial temporal sclerosis (MTS) suffer from medically refractory epilepsy requiring surgery. Because current options such as open resection, laser ablation, and Gamma Knife radiosurgery pose potential risks, such as infection, hemorrhage, and ionizing radiation, and because they often produce visual or neuropsychological deficits, the authors developed a noninvasive MRgFUS ablation strategy for mesial temporal disconnection to mitigate these risks.

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Uncertainty continues to surround mild traumatic brain injury (mTBI) diagnosis, symptoms, prognosis, and outcome due in part to a lack of objective biomarkers of injury and recovery. As mTBI gains recognition as a serious public health epidemic, there is need to identify risk factors, diagnostic tools, and imaging biomarkers to help guide diagnosis and management. One hundred and eleven patients (15-50 years old) were enrolled acutely after mTBI and followed with up to four standardized serial assessments over 3 months.

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Purpose: Diffusion tensor imaging (DTI) and quantitative susceptibility mapping (QSM) have been proposed as methods to aid in the diagnosis of amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS), both diseases affecting upper motor neurons. We test the performance of DTI and QSM alone and in combination to distinguish patients with diseases affecting upper motor neurons (ALS/PLS) from patients with other motor symptom-predominant neurologic disorders.

Methods: 3.

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Mild traumatic brain injury (mTBI) affects about 42 million people worldwide. It is often associated with headache, cognitive deficits, and balance difficulties but rarely shows any abnormalities on conventional computed tomography (CT) or magnetic resonance imaging (MRI). Although in most mTBI patients the symptoms resolve within 3 months, 10-15% of patients continue to exhibit symptoms beyond a year.

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Context: Recently, concussion has become a topic of much discussion within sports. The goal of this review is to provide an overview of the literature concerning the definition of concussion, management of initial injury, return to play, and future health risks.

Evidence Acquisition: This article reviews the most recent findings on recognizing and managing sports-related concussion, which has become a significant health risk.

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Both the size and location of injury in the brain influences the type and severity of cognitive or sensorimotor dysfunction. However, even with advances in MR imaging and analysis, the correspondence between lesion location and clinical deficit remains poorly understood. Here, structural and diffusion images from 14 healthy subjects are used to create spatially unbiased white matter connectivity importance maps that quantify the amount of disruption to the overall brain network that would be incurred if that region were compromised.

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Our goal was to determine whether performance variability during predictive visual tracking can provide a screening measure for mild traumatic brain injury (mTBI). Seventeen subjects with chronic postconcussive syndrome and 9 healthy control subjects were included in this study. Eye movements were recorded with video-oculography as the subject visually tracked a target that moved through a circular trajectory.

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Mild traumatic brain injury (mTBI) remains a challenge to accurately assess with conventional neuroimaging. Recent research holds out the promise that diffusion tensor imaging (DTI) can be used to predict recovery in mTBI patients. Unlike computed tomography or conventional magnetic resonance imaging, DTI is sensitive to microstructural axonal injury, the neuropathology that is thought to be most responsible for the persistent cognitive and behavioral impairments that often occur after mTBI.

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Inter-subject variations in white matter tract properties are known to correlate with individual differences in performance in cognitive domains such as attention. The specificity of such linkages, however, is largely unexplored at the level of specific component operations of attention associated with distinct anatomical networks. This study examines individual performance variation within three functional components of attention - alerting, orienting, and conflict processing - identified by the Attention Network Task (ANT), and relates each to inter-subject variation in a distinct set of white matter tract regions.

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