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Papers by Noam Alperin

Research paper thumbnail of Analyses of Magnetic Resonance Imaging of Cerebrospinal Fluid Dynamics Pre and Post Short and Long-Duration Space Flights

1. Hargens AR, Richardson S. Cardiovascular adaptations, fluid shifts, and countermeasures relate... more 1. Hargens AR, Richardson S. Cardiovascular adaptations, fluid shifts, and countermeasures related to space flight. Respiratory physiology & neurobiology. 2009;169 Suppl 1:S30-3. 2. Alperin N, Ranganathan S, Bagci M et al. MRI evidence of impaired CSF homeostasis in obesity-associated idiopathic intracranial hypertension. AJNR 2013;34(1):29-34 3. Tain RW, Bagci AM, Lam BL, Alperin N. Determination of cranio-spinal canal compliance distribution by MRI: Early application in IIH. JMRI 2011 34(6):1397-404 4. Alperin N, Lee SH, Loth F, et. al MR-Intracranial Pressure (ICP): A method for noninvasive measurement of intracranial pressure and elastance. Radiology. 2000; 217 (3); 877–885. 5. Alperin N, Vikingstad EM, et al. Hemodynamically independent analysis of cerebrospinal fluid and brain motion observed with dynamic phase contrast MRI. MRM 1996;35(5):741-54 6. Alperin N, Lee SH. PUBS: Pulsatility based segmentation of lumens conducting nonsteady flow.. Magnetic Resonance in Medicine (MRM...

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Research paper thumbnail of Poor sleep accelerates hippocampal and posterior cingulate volume loss in cognitively normal healthy older adults

Journal of Sleep Research

Poor sleep quality is a known risk factor for Alzheimer's disease. This longitudinal imaging ... more Poor sleep quality is a known risk factor for Alzheimer's disease. This longitudinal imaging study aimed to determine the acceleration in the rates of tissue loss in cognitively critical brain regions due to poor sleep in healthy elderly individuals. Cognitively-normal healthy individuals, aged ≥60 years, reported Pittsburgh Sleep Quality Index (PSQI) and underwent baseline and 2-year follow-up magnetic resonance imaging brain scans. The links between self-reported sleep quality, rates of tissue loss in cognitively-critical brain regions, and white matter hyperintensity load were assessed. A total of 48 subjects were classified into normal (n = 23; PSQI score <5) and poor sleepers (n = 25; PSQI score ≥5). The two groups were not significantly different in terms of age, gender, years of education, ethnicity, handedness, body mass index, and cognitive performance. Compared to normal sleepers, poor sleepers exhibited much faster rates of volume loss, over threefold in the right hippocampus and fivefold in the right posterior cingulate over 2 years. In contrast, there were no significant differences in the rates of volume loss in the cerebral and cerebellar grey and white matter between the two groups. Rates of volume loss in the right posterior cingulate were negatively associated with global PSQI scores. Poor sleep significantly accelerates volume loss in the right hippocampus and the right posterior cingulate cortex. These findings demonstrate that self-reported sleep quality explains inter-individual differences in the rates of volume loss in cognitively-critical brain regions in healthy older adults and provide a strong impetus to offer sleep interventions to cognitively normal older adults who are poor sleepers.

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Research paper thumbnail of Abstract TMP52: Basilar Artery Tortuosity and Elongation and Risk of Ischemic Stroke and Death: The Northern Manhattan Study

Stroke, 2019

Background: Basilar artery (BA) dolichoectasia is defined as dilatation, tortuosity, and/or elong... more Background: Basilar artery (BA) dolichoectasia is defined as dilatation, tortuosity, and/or elongation of the basilar artery. Hospital-based studies have demonstrated an association between BA dilatation and risk of death and stroke. We hypothesized that BA tortuosity and elongation increase risk of death and stroke independent of BA dilatation. Methods: We included stroke-free participants in the Northern Manhattan Study, a population-based prospective cohort study, with an available time of flight MRA. BA tortuosity was defined as BA localization lateral to margin of the clivus, and BA elongation as BA tip distal to margin of the sella. BA diameters were obtained with semi-automated in-house software. Primary outcomes were any death and ischemic stroke. Cox proportional hazards models were used to obtain hazards ratios [HR] and 95% confidence intervals [CI] after adjusting for demographics and vascular risks. Results: Participants (N=1032, mean age 70.7 years, 39.5% men, 65.7% His...

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Research paper thumbnail of Correction: MRI Evidence for Altered Venous Drainage and Intracranial Compliance in Mild Traumatic Brain Injury

PLoS ONE, 2013

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Research paper thumbnail of Automated Posterior Cranial Fossa Volumetry by MRI: Applications to Chiari Malformation Type I

American Journal of Neuroradiology, 2013

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Research paper thumbnail of Abstract W MP68: Brain Arterial Diameters and Risk of Vascular Events

Stroke, 2015

Objective: Inward and outward remodeling of cerebral vessels may represent alternate pathological... more Objective: Inward and outward remodeling of cerebral vessels may represent alternate pathological vascular phenotypes. Our aim was to test whether extremes of brain arterial diameters increase risk of death and vascular events. Methods: Cerebral large artery diameters were measured in 1,034 stroke-free participants from Northern Manhattan. Arteries from the Circle of Willis (8) and posterior circulation (5) were measured in regions free of stenosis, adjusted for head size, standardized, and added to create a global measure of diameters in each person. Participants were categorized into the top 5% of the diameter distribution (“outward remodelers”) and bottom 5% (“inward remodelers”), as well as an intermediate referent category (90% of population). We used logistic regression to calculate associations with risk factors and Cox models to calculate risks of outcomes after adjusting for demographic and vascular risk factors. Results: Mean follow-up was 5 ± 2 years. Inward remodelers we...

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Research paper thumbnail of Abstract TMP56: Differential Effect of Left versus Right White Matter Hyperintensity Burden on Functional Decline: The Northern Manhattan Study

Stroke, 2017

Background: We previously showed that overall brain white matter hyperintensity volume (WMHV) was... more Background: We previously showed that overall brain white matter hyperintensity volume (WMHV) was associated with accelerated long-term functional decline. Asymmetry of brain dysfunction may disrupt brain network efficiency. We hypothesized that greater left-right WMHV asymmetry was associated with functional trajectories. Methods: In the Northern Manhattan MRI study, participants had brain MRI with axial T1, T2, and fluid attenuated inversion recovery sequences, with baseline interview and examination. Volumetric WMHV distribution across 14 brain regions (brainstem, cerebellum, and bilateral frontal, occipital, temporal, and parietal lobes, and bilateral anterior and posterior periventricular white matter) was determined separately by combining bimodal image intensity distribution and atlas based methods.. Participants had annual functional assessments with the Barthel index (BI, range 0-100) over a mean of 7.3 years. Generalized estimating equations models estimated associations o...

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Research paper thumbnail of Cerebrospinal Fluid Dynamics and Cerebral Venous Drainage Patterns in Untreated Idiopathic Intracranial Hypertension

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Research paper thumbnail of Evidence for Larger Extra Ventricular Cranial CSF Volume in Idiopathic Intracranial Hypertension (IIH)

Introduction Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, is ch... more Introduction Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, is characterized by elevated intracranial pressure (ICP) of unknown cause [1]. This condition occurs at higher frequency in obese young women of childbearing age. Symptoms include debilitating headaches and visual disturbances, and papilledema is a common finding in IIH. At present, the medical treatment for IIH patients is with Acetazolamide, a carbonic anhydrase inhibitor. The lack of understanding of the pathophysiology involved limits our ability to diagnose the disease early and treat it effectively. It is widely accepted that IIH is associated with impaired absorption of CSF [2], which could potentially result with increased CSF volume leading to reduced compliance and increased ICP. Impaired CSF absorption is also the assumed cause for normal pressure hydrocephalous in the elderly. However, unlike hydrocephalous, brain ventricles remain small in IIH. Therefore, if IIH is indeed associa...

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Research paper thumbnail of Automated quantification of globe flattening by MRI in Idiopathic Intracranial Hypertension

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Research paper thumbnail of Evidence for Altered Spinal Canal Compliance and Cerebral Venous Drainage in Untreated Idiopathic Intracranial Hypertension

Acta Neurochirurgica Supplementum, 2012

Idiopathic intracranial hypertension (IIH), or pseudotumor cerebri, is a debilitating neurologica... more Idiopathic intracranial hypertension (IIH), or pseudotumor cerebri, is a debilitating neurological disorder characterized by elevated CSF pressure of unknown cause. IIH manifests as severe headaches, and visual impairments. Most typically, IIH prevails in overweight females of childbearing age and its incidence is rising in parallel with the obesity epidemic. The most accepted theory for the cause of IIH is reduced absorption of CSF due to elevated intracranial venous pressure. A comprehensive MRI study, which includes structural and physiological imaging, was applied to characterize morphological and physiological differences between a homogeneous cohort of female IIH patients and an age- and BMI-similar control group to further elucidate the underlying pathophysiology. A novel analysis of MRI measurements of blood and CSF flow to and from the cranial and spinal canal compartments employing lumped parameters modeling of the cranio-spinal biomechanics provided, for the first time, evidence for the involvement of the spinal canal compartment. The CSF space in the spinal canal is less confined by bony structures compared with the cranial CSF, thereby providing most of the craniospinal compliance. This study demonstrates that the contribution of spinal canal compliance in IIH is significantly reduced.

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Research paper thumbnail of Analysis of magnetic resonance imaging–based blood and cerebrospinal fluid flow measurements in patients with Chiari I malformation: a system approach

Neurosurgical FOCUS, 2001

Object A pilot study was performed to assess noninvasively the change in intracranial compliance ... more Object A pilot study was performed to assess noninvasively the change in intracranial compliance (ICC) and intracranial pressure (ICP) in patients with Chiari I malformation who undergo foramen magnum decompression. The working hypothesis was that the main effect of the decompressive surgery is a change in ICP. Noninvasive cine phase-contrast magnetic resonance (MR) imaging is a motion-sensitive dynamic MR imaging technique that allows for visualization and quantitation of tissue motion and flow. The authors' group has used dynamic phase-contrast MR imaging to visualize and quantify pulsatile blood and cerebrospinal fluid (CSF) flow in the craniospinal system. Methods A system approach has been used to characterize the hemodynamic–hydrodynamic coupling in the craniospinal system and to derive measures for ICC and ICP. Magnetic resonance imaging–based ICC and ICP values are derived from the ratio of the volume and pressure changes that occur naturally during each cardiac cycle. T...

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Research paper thumbnail of Magnetic resonance imaging finding of empty sella in obesity related idiopathic intracranial hypertension is associated with enlarged sella turcica

Neuroradiology, 2013

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Research paper thumbnail of Total cerebral blood flow during childhood and adolescence as assessed with phase-contrast imaging

Neuropediatrics, 2012

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Research paper thumbnail of Feasibility of MRI-Guided Pharmacologic Therapy for Idiopathic Normal Pressure Hydrocephalus (iNPH) (S04.005)

Neurology, 2012

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Research paper thumbnail of Periventricular white matter hyperintensities increase the likelihood of progression from amnestic mild cognitive impairment to dementia

Journal of Neurology, 2008

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Research paper thumbnail of Automated Quantitation of the Posterior Scleral Flattening and Optic Nerve Protrusion by MRI in Idiopathic Intracranial Hypertension

American Journal of Neuroradiology, 2013

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Research paper thumbnail of Determination of cranio-spinal canal compliance distribution by MRI: Methodology and early application in idiopathic intracranial hypertension

Journal of Magnetic Resonance Imaging, 2011

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Research paper thumbnail of MRI Evidence for Altered Venous Drainage and Intracranial Compliance in Mild Traumatic Brain Injury

Purpose: To compare venous drainage patterns and associated intracranial hydrodynamics between su... more Purpose: To compare venous drainage patterns and associated intracranial hydrodynamics between subjects who experienced mild traumatic brain injury (mTBI) and age- and gender-matched controls. Methods: Thirty adult subjects (15 with mTBI and 15 age- and gender-matched controls) were investigated using a 3T MR scanner. Time since trauma was 0.5 to 29 years (mean 11.4 years). A 2D-time-of-flight MR-venography of the upper neck was performed to visualize the cervical venous vasculature. Cerebral venous drainage through primary and secondary channels, and intracranial compliance index and pressure were derived using cine-phase contrast imaging of the cerebral arterial inflow, venous outflow, and the craniospinal CSF flow. The intracranial compliance index is the defined as the ratio of maximal intracranial volume and pressure changes during the cardiac cycle. MR estimated ICP was then obtained through the inverse relationship between compliance and ICP. Results: Compared to the controls...

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Research paper thumbnail of Cognitive and Neuroimaging Correlates of the Insomnia Severity Index in Obstructive Sleep Apnea: A Pilot-Study

Applied sciences (Basel, Switzerland), 2021

We aim to determine the sleep correlates of age-related brain loss in a sample of middle-aged to ... more We aim to determine the sleep correlates of age-related brain loss in a sample of middle-aged to older males with obstructive sleep apnea (OSA). We recruited consecutive treatment naïve male patients with moderate to severe OSA from January to November of 2019. We excluded participants if they had dementia, stroke or heart disease. We collected demographic variables and vascular risk factors. We also obtained the insomnia severity index, the Epworth sleepiness scale and the Pittsburgh sleep quality index. We also obtained computerized neurocognitive testing with the go-no-go response inhibition test, Stroop interference test, catch game test, staged information processing speed test, verbal memory test and non-verbal memory test. We derived age and education adjusted domain-specific Z-scores for global cognition, memory, attention, processing speed and executive function. We used brain MRI T1-weighted images to derive total hippocampal and gray matter volumes. Partial correlations e...

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Research paper thumbnail of Analyses of Magnetic Resonance Imaging of Cerebrospinal Fluid Dynamics Pre and Post Short and Long-Duration Space Flights

1. Hargens AR, Richardson S. Cardiovascular adaptations, fluid shifts, and countermeasures relate... more 1. Hargens AR, Richardson S. Cardiovascular adaptations, fluid shifts, and countermeasures related to space flight. Respiratory physiology & neurobiology. 2009;169 Suppl 1:S30-3. 2. Alperin N, Ranganathan S, Bagci M et al. MRI evidence of impaired CSF homeostasis in obesity-associated idiopathic intracranial hypertension. AJNR 2013;34(1):29-34 3. Tain RW, Bagci AM, Lam BL, Alperin N. Determination of cranio-spinal canal compliance distribution by MRI: Early application in IIH. JMRI 2011 34(6):1397-404 4. Alperin N, Lee SH, Loth F, et. al MR-Intracranial Pressure (ICP): A method for noninvasive measurement of intracranial pressure and elastance. Radiology. 2000; 217 (3); 877–885. 5. Alperin N, Vikingstad EM, et al. Hemodynamically independent analysis of cerebrospinal fluid and brain motion observed with dynamic phase contrast MRI. MRM 1996;35(5):741-54 6. Alperin N, Lee SH. PUBS: Pulsatility based segmentation of lumens conducting nonsteady flow.. Magnetic Resonance in Medicine (MRM...

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Research paper thumbnail of Poor sleep accelerates hippocampal and posterior cingulate volume loss in cognitively normal healthy older adults

Journal of Sleep Research

Poor sleep quality is a known risk factor for Alzheimer's disease. This longitudinal imaging ... more Poor sleep quality is a known risk factor for Alzheimer's disease. This longitudinal imaging study aimed to determine the acceleration in the rates of tissue loss in cognitively critical brain regions due to poor sleep in healthy elderly individuals. Cognitively-normal healthy individuals, aged ≥60 years, reported Pittsburgh Sleep Quality Index (PSQI) and underwent baseline and 2-year follow-up magnetic resonance imaging brain scans. The links between self-reported sleep quality, rates of tissue loss in cognitively-critical brain regions, and white matter hyperintensity load were assessed. A total of 48 subjects were classified into normal (n = 23; PSQI score <5) and poor sleepers (n = 25; PSQI score ≥5). The two groups were not significantly different in terms of age, gender, years of education, ethnicity, handedness, body mass index, and cognitive performance. Compared to normal sleepers, poor sleepers exhibited much faster rates of volume loss, over threefold in the right hippocampus and fivefold in the right posterior cingulate over 2 years. In contrast, there were no significant differences in the rates of volume loss in the cerebral and cerebellar grey and white matter between the two groups. Rates of volume loss in the right posterior cingulate were negatively associated with global PSQI scores. Poor sleep significantly accelerates volume loss in the right hippocampus and the right posterior cingulate cortex. These findings demonstrate that self-reported sleep quality explains inter-individual differences in the rates of volume loss in cognitively-critical brain regions in healthy older adults and provide a strong impetus to offer sleep interventions to cognitively normal older adults who are poor sleepers.

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Research paper thumbnail of Abstract TMP52: Basilar Artery Tortuosity and Elongation and Risk of Ischemic Stroke and Death: The Northern Manhattan Study

Stroke, 2019

Background: Basilar artery (BA) dolichoectasia is defined as dilatation, tortuosity, and/or elong... more Background: Basilar artery (BA) dolichoectasia is defined as dilatation, tortuosity, and/or elongation of the basilar artery. Hospital-based studies have demonstrated an association between BA dilatation and risk of death and stroke. We hypothesized that BA tortuosity and elongation increase risk of death and stroke independent of BA dilatation. Methods: We included stroke-free participants in the Northern Manhattan Study, a population-based prospective cohort study, with an available time of flight MRA. BA tortuosity was defined as BA localization lateral to margin of the clivus, and BA elongation as BA tip distal to margin of the sella. BA diameters were obtained with semi-automated in-house software. Primary outcomes were any death and ischemic stroke. Cox proportional hazards models were used to obtain hazards ratios [HR] and 95% confidence intervals [CI] after adjusting for demographics and vascular risks. Results: Participants (N=1032, mean age 70.7 years, 39.5% men, 65.7% His...

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Research paper thumbnail of Correction: MRI Evidence for Altered Venous Drainage and Intracranial Compliance in Mild Traumatic Brain Injury

PLoS ONE, 2013

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Research paper thumbnail of Automated Posterior Cranial Fossa Volumetry by MRI: Applications to Chiari Malformation Type I

American Journal of Neuroradiology, 2013

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Research paper thumbnail of Abstract W MP68: Brain Arterial Diameters and Risk of Vascular Events

Stroke, 2015

Objective: Inward and outward remodeling of cerebral vessels may represent alternate pathological... more Objective: Inward and outward remodeling of cerebral vessels may represent alternate pathological vascular phenotypes. Our aim was to test whether extremes of brain arterial diameters increase risk of death and vascular events. Methods: Cerebral large artery diameters were measured in 1,034 stroke-free participants from Northern Manhattan. Arteries from the Circle of Willis (8) and posterior circulation (5) were measured in regions free of stenosis, adjusted for head size, standardized, and added to create a global measure of diameters in each person. Participants were categorized into the top 5% of the diameter distribution (“outward remodelers”) and bottom 5% (“inward remodelers”), as well as an intermediate referent category (90% of population). We used logistic regression to calculate associations with risk factors and Cox models to calculate risks of outcomes after adjusting for demographic and vascular risk factors. Results: Mean follow-up was 5 ± 2 years. Inward remodelers we...

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Research paper thumbnail of Abstract TMP56: Differential Effect of Left versus Right White Matter Hyperintensity Burden on Functional Decline: The Northern Manhattan Study

Stroke, 2017

Background: We previously showed that overall brain white matter hyperintensity volume (WMHV) was... more Background: We previously showed that overall brain white matter hyperintensity volume (WMHV) was associated with accelerated long-term functional decline. Asymmetry of brain dysfunction may disrupt brain network efficiency. We hypothesized that greater left-right WMHV asymmetry was associated with functional trajectories. Methods: In the Northern Manhattan MRI study, participants had brain MRI with axial T1, T2, and fluid attenuated inversion recovery sequences, with baseline interview and examination. Volumetric WMHV distribution across 14 brain regions (brainstem, cerebellum, and bilateral frontal, occipital, temporal, and parietal lobes, and bilateral anterior and posterior periventricular white matter) was determined separately by combining bimodal image intensity distribution and atlas based methods.. Participants had annual functional assessments with the Barthel index (BI, range 0-100) over a mean of 7.3 years. Generalized estimating equations models estimated associations o...

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Research paper thumbnail of Cerebrospinal Fluid Dynamics and Cerebral Venous Drainage Patterns in Untreated Idiopathic Intracranial Hypertension

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Research paper thumbnail of Evidence for Larger Extra Ventricular Cranial CSF Volume in Idiopathic Intracranial Hypertension (IIH)

Introduction Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, is ch... more Introduction Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri, is characterized by elevated intracranial pressure (ICP) of unknown cause [1]. This condition occurs at higher frequency in obese young women of childbearing age. Symptoms include debilitating headaches and visual disturbances, and papilledema is a common finding in IIH. At present, the medical treatment for IIH patients is with Acetazolamide, a carbonic anhydrase inhibitor. The lack of understanding of the pathophysiology involved limits our ability to diagnose the disease early and treat it effectively. It is widely accepted that IIH is associated with impaired absorption of CSF [2], which could potentially result with increased CSF volume leading to reduced compliance and increased ICP. Impaired CSF absorption is also the assumed cause for normal pressure hydrocephalous in the elderly. However, unlike hydrocephalous, brain ventricles remain small in IIH. Therefore, if IIH is indeed associa...

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Research paper thumbnail of Automated quantification of globe flattening by MRI in Idiopathic Intracranial Hypertension

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Research paper thumbnail of Evidence for Altered Spinal Canal Compliance and Cerebral Venous Drainage in Untreated Idiopathic Intracranial Hypertension

Acta Neurochirurgica Supplementum, 2012

Idiopathic intracranial hypertension (IIH), or pseudotumor cerebri, is a debilitating neurologica... more Idiopathic intracranial hypertension (IIH), or pseudotumor cerebri, is a debilitating neurological disorder characterized by elevated CSF pressure of unknown cause. IIH manifests as severe headaches, and visual impairments. Most typically, IIH prevails in overweight females of childbearing age and its incidence is rising in parallel with the obesity epidemic. The most accepted theory for the cause of IIH is reduced absorption of CSF due to elevated intracranial venous pressure. A comprehensive MRI study, which includes structural and physiological imaging, was applied to characterize morphological and physiological differences between a homogeneous cohort of female IIH patients and an age- and BMI-similar control group to further elucidate the underlying pathophysiology. A novel analysis of MRI measurements of blood and CSF flow to and from the cranial and spinal canal compartments employing lumped parameters modeling of the cranio-spinal biomechanics provided, for the first time, evidence for the involvement of the spinal canal compartment. The CSF space in the spinal canal is less confined by bony structures compared with the cranial CSF, thereby providing most of the craniospinal compliance. This study demonstrates that the contribution of spinal canal compliance in IIH is significantly reduced.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Analysis of magnetic resonance imaging–based blood and cerebrospinal fluid flow measurements in patients with Chiari I malformation: a system approach

Neurosurgical FOCUS, 2001

Object A pilot study was performed to assess noninvasively the change in intracranial compliance ... more Object A pilot study was performed to assess noninvasively the change in intracranial compliance (ICC) and intracranial pressure (ICP) in patients with Chiari I malformation who undergo foramen magnum decompression. The working hypothesis was that the main effect of the decompressive surgery is a change in ICP. Noninvasive cine phase-contrast magnetic resonance (MR) imaging is a motion-sensitive dynamic MR imaging technique that allows for visualization and quantitation of tissue motion and flow. The authors' group has used dynamic phase-contrast MR imaging to visualize and quantify pulsatile blood and cerebrospinal fluid (CSF) flow in the craniospinal system. Methods A system approach has been used to characterize the hemodynamic–hydrodynamic coupling in the craniospinal system and to derive measures for ICC and ICP. Magnetic resonance imaging–based ICC and ICP values are derived from the ratio of the volume and pressure changes that occur naturally during each cardiac cycle. T...

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Research paper thumbnail of Magnetic resonance imaging finding of empty sella in obesity related idiopathic intracranial hypertension is associated with enlarged sella turcica

Neuroradiology, 2013

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Research paper thumbnail of Total cerebral blood flow during childhood and adolescence as assessed with phase-contrast imaging

Neuropediatrics, 2012

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Feasibility of MRI-Guided Pharmacologic Therapy for Idiopathic Normal Pressure Hydrocephalus (iNPH) (S04.005)

Neurology, 2012

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Research paper thumbnail of Periventricular white matter hyperintensities increase the likelihood of progression from amnestic mild cognitive impairment to dementia

Journal of Neurology, 2008

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Research paper thumbnail of Automated Quantitation of the Posterior Scleral Flattening and Optic Nerve Protrusion by MRI in Idiopathic Intracranial Hypertension

American Journal of Neuroradiology, 2013

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Determination of cranio-spinal canal compliance distribution by MRI: Methodology and early application in idiopathic intracranial hypertension

Journal of Magnetic Resonance Imaging, 2011

Bookmarks Related papers MentionsView impact

Research paper thumbnail of MRI Evidence for Altered Venous Drainage and Intracranial Compliance in Mild Traumatic Brain Injury

Purpose: To compare venous drainage patterns and associated intracranial hydrodynamics between su... more Purpose: To compare venous drainage patterns and associated intracranial hydrodynamics between subjects who experienced mild traumatic brain injury (mTBI) and age- and gender-matched controls. Methods: Thirty adult subjects (15 with mTBI and 15 age- and gender-matched controls) were investigated using a 3T MR scanner. Time since trauma was 0.5 to 29 years (mean 11.4 years). A 2D-time-of-flight MR-venography of the upper neck was performed to visualize the cervical venous vasculature. Cerebral venous drainage through primary and secondary channels, and intracranial compliance index and pressure were derived using cine-phase contrast imaging of the cerebral arterial inflow, venous outflow, and the craniospinal CSF flow. The intracranial compliance index is the defined as the ratio of maximal intracranial volume and pressure changes during the cardiac cycle. MR estimated ICP was then obtained through the inverse relationship between compliance and ICP. Results: Compared to the controls...

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Research paper thumbnail of Cognitive and Neuroimaging Correlates of the Insomnia Severity Index in Obstructive Sleep Apnea: A Pilot-Study

Applied sciences (Basel, Switzerland), 2021

We aim to determine the sleep correlates of age-related brain loss in a sample of middle-aged to ... more We aim to determine the sleep correlates of age-related brain loss in a sample of middle-aged to older males with obstructive sleep apnea (OSA). We recruited consecutive treatment naïve male patients with moderate to severe OSA from January to November of 2019. We excluded participants if they had dementia, stroke or heart disease. We collected demographic variables and vascular risk factors. We also obtained the insomnia severity index, the Epworth sleepiness scale and the Pittsburgh sleep quality index. We also obtained computerized neurocognitive testing with the go-no-go response inhibition test, Stroop interference test, catch game test, staged information processing speed test, verbal memory test and non-verbal memory test. We derived age and education adjusted domain-specific Z-scores for global cognition, memory, attention, processing speed and executive function. We used brain MRI T1-weighted images to derive total hippocampal and gray matter volumes. Partial correlations e...

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