Other

Thornhill Scientific Inc.

Tbi Innovations, LLC

Thornhill Research, Inc.

University Health Network

Joseph Fisher

Joseph A Fisher

David W Smith

Alex Vesely

James Duffin

Michael Klein

Steve Iscoe

Olivia Sobczyk

David J Mikulis

Hiroshi Sasano

David Preiss

Kevin John Vititoe

Jamison Joseph Float

Chad Michael Leeder

Julien Poublanc

Eitan Prisman

Takafumi Azami

Daniel Michael Mandell

Ron Somogyi

Marat Slessarev

Ronald Somogyi

Kevin Sam

Tehilla Adams

Adrian P Crawley

Shoji Ito

Cathie Kessler

John T Stites

Alex Stenzler

George A Volgyesi

David Smith

Ece Su Sayin

Dan Nayot

Bryan Drew Miller

Ludwik Fedorko

Eltan Prisman

Bryan Kowalchuk

Takafumi Asami

Janet Tesler

Anne Battisti-Charbonney

Alan Berdowski

Kamil Uludag

Jacob B Schulman

Deoxyhemoglobin contrast has been used to locate arteries based on the earlier blood oxygen-level dependent (BOLD) signal arrival time, higher BOLD signal strength, and shorter mean transit time. However, additional strategies of identifying arteries with oxygen modulation are required to improve the sensitivity and specificity of results. The present disclosure provides a method of distinguishing extravascular voxels from intravascular voxels based on the magnetic signal obtained from two hypoxic boluses having two different baselines. Intravascular voxels are responsive to changes in the baseline due to their high blood volume, while extravascular voxels are not affected by changes to the baseline. Amongst intravascular voxels, arteries can be distinguished from veins because the extraction fraction of the arterial blood is reduced during hypoxia, and therefore veins are less sensitive to changes in the baseline.

Identifying the vascularity of cerebral tissue in subjects using deoxyhemoglobin contrast

A method and device for reducing the damaging effects of a blast or concussive event includes applying pressure to at least one jugular vein to reduce the egress of blood from the cranial cavity during the incidence of the concussive event. Reducing blood out flow from the cranial cavity increases intracranial pressure of the cerebrospinal fluid to reduce the risk of traumatic brain injury and injuries to the spinal column. Reducing blood out flow further increases the intracranial pressure, and thereby increases the pressure of the cochlear fluid, the vitreous humor and the cerebrospinal fluid to thereby reduce the risk of injury to the inner ear, internal structure of the eye and of the spinal column. In addition, increasing intracranial pressure reduces the likelihood of brain injury and any associated loss of olfactory function.

Methods and devices to reduce damaging effects of concussive or blast forces on a subject

An apparatus and method for assessing vascular compliance in subjects with multiple sclerosis using sequential gas delivery is provided. The apparatus includes a gas delivery device and a processor. The processor controls the gas delivery device to deliver a first and second gas during a single inspiration. The first gas contains a mixture of oxygen and carbon dioxide necessary to target an end-tidal concentration of the two gases. The second gas includes a concentration of carbon dioxide equal to the target end-tidal concentration of carbon dioxide.

Testing for neurovascular uncoupling in multiple sclerosis using sequential gas delivery versus fixed inspired CO

Z maps combined with a standardized stimulus in the form of a targeted arterial partial pressures of carbon dioxide provide surprisingly enhanced images for the assessment of pathological CVR. For example, the z-map assessment of patients with known steno-occlusive diseases of the cervico-cerebral vasculature showed an enhanced resolution of the presence, localization, and severity of the pathological CVR. Z-map have been found to be useful to reduce the confounding effects of test-to-test, subject-to-subject, and platform-to-platform variability for comparison of CVR images showing the importance of combining this analysis with the standardized stimulus.

Imaging abnormalities in vascular response

A respiratory gas delivery system monitors gas flow over the course of a breath in real time and uses this parameter to simulate, in whole or part, the function of a reference respiratory gas delivery system, in particular structural features, particularly structural components of parts of the reference system, to overcome a structural limitation of the reference system.

Virtual respiratory gas delivery systems and circuits

A method of controlling a gas delivery apparatus including an apparatus controllable variable using an iterative algorithm to deliver a test gas (TG) for non-invasively determining a subject's pulmonary blood flow comprising iteratively generating and evaluating test values of a iterated variable based on an iterative algorithm in order output a test value of the iterated variable that meets a test criterion wherein iterative algorithm is characterized in that it defines a test mathematical relationship between the at least one apparatus controllable variable, the iterated variable and an end tidal concentration of test gas attained by setting the apparatus controllable variable, such that the iterative algorithm is determinative of whether iteration on the test value satisfies a test criterion or iteratively generates a progressively refined test value.

Non-invasive cardiac output determination

A method of identifying alveolar ventilation (V) in a subject, the method comprising: (1) using a breathing circuit which, at exhalation, keeps exhaled gas separate from inhaled gas and at inhalation, when a first gas set (FGS) flow is less than the subject's minute ventilation (V), results in a subject inhaling FGS first and then a second gas set (SGS), for the balance of inhalation; (2) setting the FGS flow at a rate greater that V; (3) measuring an end tidal COconcentration at a steady state; (4) progressively lowering the FGS flow until a time equal to a recirculation time of COin the subject; and (5) deriving Vas the rate of FGS flow at the intersection between an average PETCOin a steady state and a line fit to the PETCOvalues after the rise in PETCOvalues begins until the recirculation time.

Method of measuring cardiac related parameters non-invasively via the lung during spontaneous and controlled ventilation

An apparatus and method for controlling the end tidal partial pressure of a gas X in a subject's lung, and to the use of such an apparatus and method for research, diagnostic and therapeutic purposes, wherein the method consists of: &#x2014;obtaining input of a series of logistically attainable PetX values for a series of respective breaths: &#x2014;determining an amount of gas X required to be inspired by the subject in an inspired gas to target the PetX for each of said respective breaths: and&#x2014;controlling a gas delivery device to deliver the amount of gas in a volume of gas delivered to the subject in each of said respective breaths to target the respective PetX for that breath.

Method and apparatus to attain and maintain target arterial blood gas concentrations using ramp sequences

A processor obtains input of a logistically attainable end tidal partial pressure of gas X (PetX[i]) for one or more respective breaths [i] and input of a prospective computation of an amount of gas X required to be inspired by the subject in an inspired gas to target the PetX[i]for a respective breath [i] using inputs required to utilize a mass balance relationship, wherein one or more values required to control the amount of gas X in a volume of gas delivered to the subject is output from an expression of the mass balance relationship. The mass balance relationship is expressed in a form which takes into account (prospectively), for a respective breath [i], the amount of gas X in the capillaries surrounding the alveoli and the amount of gas X in the alveoli, optionally based on a model of the lung which accounts for those sub-volumes of gas in the lung which substantially affect the alveolar gas X concentration affecting mass transfer.

Apparatus to attain and maintain target end tidal partial pressure of a gas

A system for reducing the damaging effects of radiant energy, blast, or concussive events includes applying pressure to at least one jugular vein to reduce the egress of blood from the cranial cavity during or before the incidence of the imparting event. Reducing blood outflow from the cranial cavity increases intracranial volume and/or pressure of the cerebrospinal fluid to reduce the risk of traumatic brain injury and injuries to the spinal column. Reducing blood outflow further increases the intracranial pressure and volume, and thereby increases the pressure and volume of the cochlear fluid, the vitreous humor and the cerebrospinal fluid to thereby reduce the risk of injury to the inner ear, internal structure of the eye and of the spinal column. In addition, increasing intracranial pressure and volume reduces the likelihood of brain injury and any associated loss of olfactory function.

Devices and systems to mitigate traumatic brain and other injuries caused by concussive or blast forces

A system for detecting an abnormality in a subject's cerebrovascular response to a vasoactive stimulus in at least one region of interest (ROI) of the subject's brain The system comprises a system for generating the vasoactive stimulus (SVS), the SVS including a gas delivery device and a control system operable to deliver controlled amounts of carbon dioxide effective to attain at least one of a series of targeted increments or decrements in the subject's PetCO, for a series of respective intervals; an imaging system comprising an MRI scanner for generating response signals corresponding to the subject's vasoactive response to the vasoactive stimulus; and a computer for analyzing the response signals, the computer including program code for computing at least one value representing a quantitative measure of the subject's cerebrovascular reactivity for the ROI, wherein the at least one value is obtained for a specific portion of the subject's vasoactive response in the ROI, the specific portion of the subject's vasoactive response corresponding to a sub-series of the at least one of a series of targeted increments or decrements in the subject's PetCO, the sub-series characterized in that the specific portion of the subject's vasoactive response is the portion sensitive to quantifying a reduction in cerebrovascular reactivity.

Imaging reductions in cerebrovascular reactivity

A system for controlling an amount of at least one gas X in a subject's lung to target at least one end tidal partial pressure of at least one gas X (PetX) uses a control system for controlling the gas delivery device, wherein the control system implements a sequential gas delivery system and a feedback algorithm which compares a PetXfor a respective breath of variable size and preferably a respective current PetX value measured by a measurement system, to obtain an error signal, the feedback algorithm adapted for generating a control signal based on the error signal, the control signal determining the amount of gas X to be inspired by the subject in at least a first portion of a respective ensuing respective inspiratory cycle to target PetXfor the respective interval.

Controlling arterial blood gas concentration

A method and device for reducing the damaging effects of radiant energy, blast, or concussive events includes applying pressure to at least one jugular vein to reduce the egress of blood from the cranial cavity during or before the incidence of the imparting event. Reducing blood outflow from the cranial cavity increases intracranial volume and/or pressure of the cerebrospinal fluid to reduce the risk of traumatic brain injury and injuries to the spinal column. Reducing blood outflow further increases the intracranial pressure and volume, and thereby increases the pressure and volume of the cochlear fluid, the vitreous humor and the cerebrospinal fluid to thereby reduce the risk of injury to the inner ear, internal structure of the eye and of the spinal column. In addition, increasing intracranial pressure and volume reduces the likelihood of brain injury and any associated loss of olfactory function.

Methods and devices to reduce the likelihood of injury from concussive or blast forces

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Toronto, Canada

Joseph A Fisher