Scott Raymond - Profile on Academia.edu (original) (raw)

Papers by Scott Raymond

Spontaneous Intracranial Hypotension Caused by Thoracic Disc Disease

Headache: The Journal of Head and Face Pain, 2020

Does including neck CTA in work-up of suspected intracranial hemorrhage add value?

Emergency Radiology, 2018

PurposeNeck CT angiography (CTA) is frequently performed in conjunction with head CTA in patients... more PurposeNeck CT angiography (CTA) is frequently performed in conjunction with head CTA in patients presenting with clinical signs and symptoms concerning for acute intracranial hemorrhage, despite relatively low appropriateness (ACR Appropriateness Criteria 2–6). This decision is sometimes justified by suggesting that CTA neck findings are useful in planning subsequent catheter angiography.MethodsWe investigated the value of neck CTA in patients with suspected acute intracranial hemorrhage by reviewing 220 head and neck CTAs performed in our emergency room over a 24-month period for the indication of hemorrhage or headache. Images were reviewed by two neurointerventionalists to address the value of the neck CTA for planning catheter angiography.ResultsFindings helpful for performing catheter angiography were observed on neck CTA in 22% (Cohen kappa 0.65), and included anatomical arch variants such as a bovine arch, direct vertebral artery arch origin, and aberrant subclavian artery. However, findings that might substantially prolong angiography for more than 10 min if unknown occurred in 5% (Cohen kappa 0.69). Incidental findings prompting additional imaging or significant clinical action occurred in 20%. Subarachnoid hemorrhage on noncontrast head CT was strongly associated with a need for subsequent angiography.ConclusionsAlthough CTA neck can provide helpful information for planning catheter angiography, it rarely uncovers findings that would significantly prolong the procedure if unknown. Neck CTA is therefore only recommended in patients with a confirmed intracranial hemorrhage in a pattern consistent with aneurysm or arteriovenous shunt.

Journal of neurointerventional surgery, Jan 13, 2018

The LVIS Blue is an FDA-approved stent with 28% metallic coverage that is indicated for use in co... more The LVIS Blue is an FDA-approved stent with 28% metallic coverage that is indicated for use in conjunction with coil embolization for the treatment of intracranial aneurysms. Given a porosity similar to approved flow diverters and higher than currently available intracranial stents, we sought to evaluate the effectiveness of this device for the treatment of intracranial aneurysms. We performed an observational single-center study to evaluate initial occlusion and occlusion at 6-month follow-up for patients treated with the LVIS Blue in conjunction with coil embolization at our institution using the modified Raymond-Roy classification (mRRC), where mRRC 1 indicates complete embolization, mRRC 2 persistent opacification of the aneurysm neck, mRRC 3a filling of the aneurysm dome within coil interstices, and mRRC 3b filling of the aneurysm dome. Sixteen aneurysms were treated with the LVIS Blue device in conjunction with coil embolization with 6-month angiographic follow-up. Aneurysms w...

Imaging Brain Collaterals: Quantification, Scoring, and Potential Significance

Topics in magnetic resonance imaging : TMRI, 2017

Leptomeningeal collaterals provide the primary source of perfusion to ischemic brain tissue follo... more Leptomeningeal collaterals provide the primary source of perfusion to ischemic brain tissue following the onset of acute ischemic stroke and are becoming an important imaging biomarker for stroke therapy triage. Collateral circulation is predictive of infarct growth, end infarct volume, and response to endovascular therapy. The strength of the collateral circulation varies among patients and is partially dependent on genetic and modifiable risk factors. Collateral circulation may be assessed by standard angiographic techniques, including digital subtraction angiography, computed tomography and magnetic resonance (MR) angiography, as well as a growing array of advanced MR techniques including arterial spin labeling and dynamic MR angiography. Simple scoring systems are used to estimate the relative strength of the collateral circulation for a given patient, although there are some discrepancies in the predictive value of these systems. In this review, we discuss methods and technique...

CT and MRI of Rare Extraintestinal Manifestations of Inflammatory Bowel Disease in Children and Adolescents

Journal of Pediatric Gastroenterology and Nutrition, 2016

Inflammatory bowel disease (IBD) is associated with a spectrum of extraintestinal manifestations ... more Inflammatory bowel disease (IBD) is associated with a spectrum of extraintestinal manifestations (EIMs) affecting many organ systems. EIMs can occur in over 40% of IBD patients and are associated with significant morbidity. They occur at any time point in the course of disease, often during an active phase of bowel inflammation, but sometimes preceding bowel disease. Prompt recognition of EIMs enables timely and more effective therapy. Physicians who image patients with IBD should be aware of the myriad extraintestinal conditions that may be detected on imaging studies, both within and outside of the abdomen, as they may predate the diagnosis of IBD. Cross sectional imaging of unusual conditions associated with IBD will be presented, including pathology in the hepatobiliary, pancreatic, genitourinary, musculoskeletal, mucocutaneous, vascular, neurologic and pulmonary systems.

Molecular imaging tools for studying Alzheimer's disease

IC-P-126

Alzheimers Dement, 2006

Focused ultrasound thermal surgery, imaging, and elastometry using the same phased array: feasibility study

IEEE Ultrasonics Symposium, 2004

I. MOTIVATION In recent years, MRI-guided focused ultrasound surgery has proven effective in a va... more I. MOTIVATION In recent years, MRI-guided focused ultrasound surgery has proven effective in a variety of clinical applications [1-2]. In these procedures, focused ultrasound is used as a thermal scalpel to ablate cancerous tissue. The process is monitored by MRI ...

Biomedical Optics and 3-D Imaging, 2012

A direct approach to time domain fluorescence tomography based on asymptotic lifetime analysis

SPIE Proceedings, 2007

ABSTRACT A theoretical framework is presented that allows a lifetime based analysis of the entire... more ABSTRACT A theoretical framework is presented that allows a lifetime based analysis of the entire temporal diffuse fluorescence response curve from a turbid medium. Optimization studies using singular value decomposition analysis show that direct time domain fluorescence reconstructions are optimally performed using a few points near the peak and rise portions of the temporal response. It is also shown that the initial portion of the fluorescent response curve offers superior contrast-to-noise performance, while the late decay portions offer minimal cross-talk between multiple lifetime components.

Ultrasound in Medicine & Biology, 2005

Focused ultrasound offers a method to disrupt the blood-brain barrier (BBB) noninvasively and rev... more Focused ultrasound offers a method to disrupt the blood-brain barrier (BBB) noninvasively and reversibly at targeted locations. The purpose of this study was to test the safety of this method by searching for ischemia and apoptosis in areas with BBB disruption induced by pulsed ultrasound in the presence of preformed gas bubbles and by looking for delayed effects up to one month after sonication. Pulsed ultrasound exposures (sonications) were performed in the brains of 24 rabbits under monitoring by magnetic resonance imaging (MRI) (ultrasound: frequency ‫؍‬ 1.63 MHz, burst length ‫؍‬ 100 ms, PRF ‫؍‬ 1 Hz, duration ‫؍‬ 20 s, pressure amplitude 0.7 to 1.0 MPa). Before sonication, an ultrasound contrast agent (Optison ® , GE Healthcare, Milwaukee, WI, USA) was injected IV. BBB disruption was confirmed with contrast-enhanced MR images. Whole brain histologic examination was performed using haematoxylin and eosin staining for general histology, vanadium acid fuchsin-toluidine blue staining for ischemic neurons and TUNEL staining for apoptosis. The main effects observed were tiny regions of extravasated red blood cells scattered around the sonicated locations, indicating affected capillaries. Despite these vasculature effects, only a few cells in some of the sonicated areas showed evidence for apoptosis or ischemia. No ischemic or apoptotic regions were detected that would indicate a compromised blood supply was induced by the sonications. No delayed effects were observed either by MRI or histology up to 4 wk after sonication. Ultrasound-induced BBB disruption is possible without inducing substantial vascular damage that would result in ischemic or apoptotic death to neurons. These findings indicate that this method is safe for targeted drug delivery, at least when compared with the currently available invasive methods.

PLoS ONE, 2008

Alzheimer's disease is a neurodegenerative disorder typified by the accumulation of a small prote... more Alzheimer's disease is a neurodegenerative disorder typified by the accumulation of a small protein, beta-amyloid, which aggregates and is the primary component of amyloid plaques. Many new therapeutic and diagnostic agents for reducing amyloid plaques have limited efficacy in vivo because of poor transport across the blood-brain barrier. Here we demonstrate that low-intensity focused ultrasound with a microbubble contrast agent may be used to transiently disrupt the blood-brain barrier, allowing non-invasive, localized delivery of imaging fluorophores and immunotherapeutics directly to amyloid plaques. We administered intravenous Trypan blue, an amyloid staining red fluorophore, and anti-amyloid antibodies, concurrently with focused ultrasound therapy in plaque-bearing, transgenic mouse models of Alzheimer's disease with amyloid pathology. MRI guidance permitted selective treatment and monitoring of plaque-heavy anatomical regions, such as the hippocampus. Treated brain regions exhibited 16.565.4-fold increase in Trypan blue fluorescence and 2.761.2-fold increase in anti-amyloid antibodies that localized to amyloid plaques. Ultrasound-enhanced delivery was consistently reproduced in two different transgenic strains (APPswe:PSEN1dE9, PDAPP), across a large age range (9-26 months), with and without MR guidance, and with little or no tissue damage. Ultrasound-mediated, transient blood-brain barrier disruption allows the delivery of both therapeutic and molecular imaging agents in Alzheimer's mouse models, which should aid pre-clinical drug screening and imaging probe development. Furthermore, this technique may be used to deliver a wide variety of small and large molecules to the brain for imaging and therapy in other neurodegenerative diseases.

Optics Letters, 2008

Unsteady flow around an oscillating plate cascade and that through a single compressor rotor subj... more Unsteady flow around an oscillating plate cascade and that through a single compressor rotor subject to vibration have been computationally studied, aimed at examining the predictive ability of two low fidelity frequency methods compared with a high fidelity time-domain solution method for aeroelasticity. The computational solutions demonstrate the capabilities of the frequency domain methods compared with the nonlinear time-domain solution method in capturing small perturbations in the unsteady flow. They also show the great advantage of significant CPU time saving by the frequency methods over the nonlinear time method. Comparisons of two different frequency methods, nonlinear harmonic and phase solution method, show that these methods can produce different results due to the differences in numeric and physical conditioning. The results obtained using phase solutions method are in better agreement with the nonlinear time-domain solution. This is because the same numeric and physical conditioning are used in both the nonlinear time-domain method and phase solution frequency domain method.

Optics Letters, 2009

We show that fluorescence lifetime is a powerful contrast mechanism that can enhance the whole-bo... more We show that fluorescence lifetime is a powerful contrast mechanism that can enhance the whole-body imaging of fluorescent proteins (FPs), in the presence of background tissue autofluorescence (AF). The nonexponential AF decay is characterized from time-domain (TD) measurements on multiple nude mice and separated from the FP fluorescence using a linear fit to a priori basis functions. We illustrate this approach using an orthotopic mouse tumor model of breast adenocarcinoma. We also report that four commonly used FPs show distinct lifetimes, indicating their suitability for in vivo lifetime multiplexing. These results suggest the potential for exploiting fluorescence lifetime for imaging FPs for a variety of whole-body small-animal imaging applications.

Optics Express, 2006

A general linear model for time domain (TD) fluorescence tomography is presented that allows a li... more A general linear model for time domain (TD) fluorescence tomography is presented that allows a lifetime-based analysis of the entire temporal fluorescence response from a turbid medium. Simulations are used to show that TD fluorescence tomography is optimally performed using two complementary approaches: A direct TD analysis of a few time points near the peak of the temporal response, which provides superior resolution; and an asymptotic multi-exponential analysis based tomography of the decay portion of the temporal response, which provides accurate localization of yield distributions for various lifetime components present in the imaging medium. These results indicate the potential of TD technology for biomedical imaging with lifetime sensitive targeted probes, and provide useful guidelines for an optimal approach to fluorescence tomography with TD data.

Journal of the American Chemical Society, 2009

Amyloid-β (Aβ) deposits have been identified as key players in the progression of Alzheimer's dis... more Amyloid-β (Aβ) deposits have been identified as key players in the progression of Alzheimer's disease (AD). Recent evidence indicates that the deposits probably precede and induce the neuronal atrophy. Therefore, methods that enable monitoring the pathology before clinical symptoms are observed would be beneficial for the early AD detection. Here, we report the design, synthesis, and testing of a curcumin derivatized near infrared (NIR) probe CRANAD-2. Upon interacting with Aβ aggregates, CRANAD-2 undergoes a range of changes, which include a 70-fold fluorescence intensity increase, a 90 nm blue-shift (from 805 nm to 715 nm), and a large increase in quantum yield. Moreover, this probe also shows a high affinity for Aβ aggregates (Kd = 38.0 nM), a reasonable Log P value (Log P = 3), considerable stability in serum and a weak interaction with albumin. After intravenous injection of this probe, 19-month old Tg2576 mice exhibited significantly higher relative signal than that of the control mice over the same period of time. In summary, CRANAD-2 meets all the requirements for a NIR contrast agent for the detection of Aβ plaques both in vitro and in vivo. Our data point towards the feasibility of monitoring the progress of the disease by NIR imaging with CRANAD-2. In addition, we believe that our probe could be potentially used as a tool for drug screening.

Journal of Biomedical Optics, 2010

Near-infrared ͑NIR͒ fluorescence tomography of multiple fluorophores has previously been limited ... more Near-infrared ͑NIR͒ fluorescence tomography of multiple fluorophores has previously been limited by the bandwidth of the NIR spectral regime and the broad emission spectra of most NIR fluorophores. We describe in vivo tomography of three spectrally overlapping fluorophores using fluorescence lifetime-based separation. Timedomain images are acquired using a voltage-gated, intensified chargecoupled device ͑CCD͒ in free-space transmission geometry with 750 nm Ti:sapphire laser excitation. Lifetime components are fit from the asymptotic portion of fluorescence decay curve and reconstructed separately with a lifetime-adjusted forward model. We use this system to test the in vivo lifetime multiplexing suitability of commercially available fluorophores, and demonstrate lifetime multiplexing in solution mixtures and in nude mice. All of the fluorophores tested exhibit nearly monoexponential decays, with narrow in vivo lifetime distributions suitable for lifetime multiplexing. Quantitative separation of two fluorophores with lifetimes of 1.1 and 1.37 ns is demonstrated for relative concentrations of 1:5. Finally, we demonstrate tomographic imaging of two and three fluorophores in nude mice with fluorophores that localize to distinct organ systems. This technique should be widely applicable to imaging multiple NIR fluorophores in 3-D.

Modular design for in vivo optical imaging and ultrasound treatment in the murine brain

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2007

Simultaneous optical imaging and ultrasound exposure to the brain is challenging due to geometric... more Simultaneous optical imaging and ultrasound exposure to the brain is challenging due to geometric constraints. We demonstrate sonication through the ventral surface of the mouse, leaving the dorsal aspect free for imaging. Ultrasound components are integrated into a commercial multiphoton microscope, and animals are imaged during ultrasound-induced blood-brain barrier disruption.

Acoustic transmission losses and field alterations due to human scalp hair

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2005

Hair is a potential transmission barrier for diagnostic and therapeutic ultrasound. We tested hai... more Hair is a potential transmission barrier for diagnostic and therapeutic ultrasound. We tested hair phantoms for insertion losses and field effects at 0.27-2.8 MHz. The negligible losses observed below 0.5 MHz suggest that, at such frequencies, hair removal is unnecessary for low-power imaging or therapeutic applications.

IEEE Transactions on Medical Imaging, 2008

We describe the application of a time domain diffuse fluorescence tomography system for whole bod... more We describe the application of a time domain diffuse fluorescence tomography system for whole body small animal imaging. The key features of the system are the use of point excitation in free space using ultrashort laser pulses and noncontact detection using a gated, intensified charge-coupled device (CCD) camera. Mouse shaped epoxy phantoms, with embedded fluorescent inclusions, were used to verify the performance of a recently developed asymptotic lifetime-based tomography algorithm. The asymptotic algorithm is based on a multiexponential analysis of the decay portion of the data. The multiexponential model is shown to enable the use of a global analysis approach for a robust recovery of the lifetime components present within the imaging medium. The surface boundaries of the imaging volume were acquired using a photogrammetric camera integrated with the imaging system, and implemented in a Monte-Carlo model of photon propagation in tissue. The tomography results show that the asymptotic approach is able to separate axially located fluorescent inclusions centered at depths of 4 and 10 mm from the surface of the mouse phantom. The fluorescent inclusions had distinct lifetimes of 0.5 and 0.95 ns. The inclusions were nearly overlapping along the measurement axis and shown to be not resolvable using continuous wave (CW) methods. These results suggest the practical feasibility and advantages of a time domain approach for whole body small animal fluorescence molecular imaging, particularly with the use of lifetime as a contrast mechanism. Index Terms-Fluorescence diffuse optical tomography, lifetime-based sensing, molecular imaging, time-resolved imaging. F LUORESCENCE diffuse optical tomography [1]- [35] based on extrinsic contrast agents offers several advantages over intrinsic absorption contrast diffuse optical tomography. Most important of these is the use of the red-shifted fluorescence emission to isolate signal arising from the fluorophores inside the tissue, while rejecting the incident light at the excitation wavelength. Recent advances in the engineering