A5037462628- Spinal Dysraphism and Malformations
- Cerebrospinal fluid and hydrocephalus
- Coronary Interventions and Diagnostics
- Head and Neck Surgical Oncology
- Cardiovascular Health and Disease Prevention
- Spinal Fractures and Fixation Techniques
- Spinal Cord Injury Research
- Fluid Dynamics and Turbulent Flows
- Peripheral Artery Disease Management
- Cerebrovascular and Carotid Artery Diseases
- Fetal and Pediatric Neurological Disorders
- Central Venous Catheters and Hemodialysis
- Traumatic Brain Injury and Neurovascular Disturbances
- Advanced MRI Techniques and Applications
- Neurosurgical Procedures and Complications
- Vascular Procedures and Complications
- Aortic aneurysm repair treatments
- Teratomas and Epidermoid Cysts
- Infectious Diseases and Tuberculosis
- Intracranial Aneurysms: Treatment and Complications
- Cardiac and Coronary Surgery Techniques
- Advanced Neuroimaging Techniques and Applications
- Photoacoustic and Ultrasonic Imaging
- Mechanical Circulatory Support Devices
- Diagnosis and Treatment of Venous Diseases
Northeastern University
2021-2025
University of Akron
2013-2022
Brown University
2021
University Health System
2021
Michigan Medicine
2021
Innsbruck Medical University
2019
Conquer Chiari
2011
University of Illinois Chicago
2000-2009
Argonne National Laboratory
2006
University of Chicago
2000-2005
To develop a noninvasive method for intracranial elastance and pressure (ICP) measurement.Intracranial volume changes were calculated from magnetic resonance (MR) imaging measurements of cerebrospinal fluid (CSF) blood flow. The change was the net transcranial CSF volumetric flow rates. in derived gradient velocity. An index ratio to change. reproducibility measurement established four five healthy volunteers. measured compared with invasive ICP patients an intraventricular catheter at MR...
Computational fluid dynamics (CFD) modeling of nominally patient-specific cerebral aneurysms is increasingly being used as a research tool to further understand the development, prognosis, and treatment brain aneurysms. We have previously developed virtual angiography indirectly validate CFD-predicted gross flow against routinely acquired digital subtraction angiograms. Toward more direct validation, here we compare detailed, velocity fields those measured using particle imaging velocimetry...
The fluid that resides within cranial and spinal cavities, cerebrospinal (CSF), moves in a pulsatile fashion to from the cavity. This motion can be measured by magnetic resonance imaging (MRI) may of clinical importance diagnosis several brain cord disorders such as hydrocephalus, Chiari malformation, syringomyelia. In present work, geometric hydrodynamic characterization an anatomically relevant canal model is presented. We found inertial effects dominate flow field under normal...
Purpose To validate a real‐time phase contrast magnetic resonance imaging (RT‐PCMRI) sequence in controlled phantom model, and to quantify the relative contributions of respiration cardiac pulsations on cerebrospinal fluid (CSF) velocity at level foramen magnum (FM). Materials Methods 3T MRI techniques, vitro studies used realistic model spinal subarachnoid space driven by pulsatile flow waveforms mimicking respiratory components CSF flow. Subsequently, was measured continuously during...
Stimulated by a recent controversy regarding pressure drops predicted in giant aneurysm with proximal stenosis, the present study sought to assess variability prediction of pressures and flow wide variety research groups. In phase I, lumen geometry, rates, fluid properties were specified, leaving each group choose their solver, discretization, solution strategies. Variability was assessed having interpolate results onto standardized mesh centerline. For II, physical model geometry...
Microglia, the resident immune cells of central nervous system, exist in either a "resting" state associated with physiological tissue surveillance or an "activated" neuroinflammation. We recently showed that ATP is primary chemoattractor to damage vivo and elicits opposite effects on motility activated microglia vitro through activation adenosine A2A receptors. However, whether systemic inflammation affects microglial responses remains largely unknown. Using two-photon imaging mice, we show...
Abstract MR phase velocity mapping was used to calculate wall shear stress (WSS) in the suprarenal and infrarenal abdominal aorta, two sites with very different proclivities for development of atherosclerosis. For eight subjects studied, average value mean (tune averaged over cardiac cycle) WSS aorta 10.4 dynes/cm 2 at posterior 8.6 anterior wall. In values were 4.7 6.1 Peak cycle 48 54 walls respectively, 33 30 respectively. Wide variation found both peak among subjects. However, 28 32...
Flow behavior in models of end-to-side vascular graft anastomoses was studied under steady and pulsatile flow conditions. Models were constructed to simulate geometries employed experimental studies on intimal thickening a canine model. Reynolds numbers, division the outflow tracts waveform taken from measurements obtained Flows scaled-up, transparent visualized with white, neutrally buoyant particles which photographed laser illumination also recorded video tape bright incandescent light....
Blood flow in end-to-side autogenous or prosthetic graft anastomoses is of great interest to biomedical researchers because the biomechanical force profile engendered by blood disturbances at such geometric transitions thought play a significant role vascular remodeling and failure. Thus, investigators have extensively studied anastomotic patterns relation failure with objective enabling design more optimal geometry. In contrast arterial bifurcations, surgically created can be modified yield...
Elevated or reduced velocity of cerebrospinal fluid (CSF) at the craniovertebral junction (CVJ) has been associated with type I Chiari malformation (CMI). Thus, quantification hydrodynamic parameters that describe CSF dynamics could help assess disease severity and surgical outcome. In this study, we methodology to quantify near CVJ upper cervical spine utilizing subject-specific computational (CFD) simulations based on in vivo MRI measurements flow geometry. Hydrodynamic were computed for a...
Cerebrospinal fluid (CSF) dynamics in the spinal subarachnoid space (SSS) have been thought to play an important pathophysiological role syringomyelia, Chiari I malformation (CM), and a intrathecal drug delivery. Yet, impact that fine anatomical structures, including nerve roots denticulate ligaments (NRDL), on SSS CSF is not clear. In present study we assessed of NRDL cervical SSS. The 3D geometry was reconstructed based manual segmentation MRI images healthy volunteer patient with CM....
Objective Our objective was to use episodic memory and executive function tests determine whether or not Chiari Malformation Type I (CM) patients experience cognitive dysfunction. Background CM is a neurological syndrome in which the cerebellum descends into cervical spine causing neural compression, severe headaches, neck pain, number of other physical symptoms. While primarily disorder cervico-medullary junction, both clinicians researchers have suspected deficits higher-level function....
Chiari malformation Type I (CMI) is characterized by herniation of the cerebellar tonsils through foramen magnum. The pathophysiology CMI not well elucidated; however, prevailing theory focuses on underdevelopment posterior cranial fossa which results in tonsillar herniation. Symptoms are believed to be due causing resistance natural flow cerebrospinal fluid (CSF) and exerting a mass effect nearby neural tissue. However, asymptomatic cases vastly outnumber symptomatic ones it known why some...
Background : Intimal hyperplastic thickening (IHT) is a frequent cause of prosthetic bypass graft failure. Induction and progression IHT thought to involve number mechanisms related variation in the flow field, injury nature conduit. This study was designed examine relative contribution wall shear stress induction at defined regions experimental end-to-side anastomoses. Methods Results: The distribution determined distal anastomosis seven canine Iliofemoral PTFE grafts after 12 weeks...
Various hemodynamic factors have been implicated in vascular graft intimal hyperplasia, the major mechanism contributing to chronic failure of small-diameter grafts. However, a thorough knowledge flow field is needed order determine role hemodynamics and how these affect underlying biological processes. Computational fluid dynamics offers much more versatility resolution than vitro or vivo methods, yet computations must be validated by careful comparison with experimental data. Whereas...
We present experimental and computational results that describe the level, distribution, importance of velocity fluctuations within venous anastomosis an arteriovenous graft. The motivation this work is to understand better biomechanical forces in development intimal hyperplasia these grafts. Steady-flow vitro studies (Re=1060 1820) were conducted a graft model represents measure by means laser Doppler anemometry. Numerical simulations with same geometry flow conditions employing spectral...
Full explanation for the pathogenesis of syringomyelia (SM), a neuropathology characterized by formation cystic cavity (syrinx) in spinal cord (SC), has not yet been provided. It hypothesized that abnormal cerebrospinal fluid (CSF) pressure, caused subarachnoid space (SAS) flow blockage (stenosis), is an underlying cause syrinx and subsequent pain patient. However, paucity detailed vivo pressure data made theoretical explanations difficult to reconcile. In order understand complex...
OBJECTIVE Chiari malformation Type I (CM-I) is typically defined on imaging by a cerebellar tonsil position ≥ 5 mm below the foramen magnum. Low frequent incidental finding brain or cervical spine imaging, even in asymptomatic individuals. Nonspecific symptoms (e.g., headache and neck pain) are common those with low as well normal position, leading to uncertainty regarding appropriate management for many patients nonspecific symptoms. Because not strictly correlated presence of typical CM-I...
The flow field inside a model of polytetrafluoroethylene (PTFE) canine artery end-to-side bypass graft was studied under steady conditions using laser-Doppler anemometry. anatomically realistic in vitro constructed to incorporate the major geometric features vivo anastomosis geometry, most notably larger than host diameter. velocity measurements at Reynolds number 208, based on diameter, show be three dimensional nature. wall shear stress distribution, computed from near-wall gradients,...