Olivia Sobczyk
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Persistent Steal Physiology during a Ramp Cerebrovascular Reactivity Assessment Correlates with Severe Cortical Thinning in Steno-Occlusive Disease Open
BOLD＝blood-oxygen-level-dependent; CVR＝cerebrovascular reactivity.
Cerebrovascular reactivity differences in healthy cerebral gray and white matter Open
Purpose To quantify the speed and magnitude of cerebrovascular reactivity (CVR) metrics in hemispheric gray and white matter. Methods A standardized isoxic hypercapnic cerebrovascular stimulus was administered using an automated arterial g…
View article: NIMG-23. A NOVEL APPROACH TO PERFUSION MRI STUDIES IN BRAIN TUMOR PATIENTS USING ENDOGENOUS DEOXYHEMOGLOBIN AS A CONTRAST AGENT: A PROOF-OF-CONCEPT STUDY
NIMG-23. A NOVEL APPROACH TO PERFUSION MRI STUDIES IN BRAIN TUMOR PATIENTS USING ENDOGENOUS DEOXYHEMOGLOBIN AS A CONTRAST AGENT: A PROOF-OF-CONCEPT STUDY Open
BACKGROUND Assessment of resting perfusion in brain tumors is clinically relevant and relies on dynamic susceptibility contrast magnetic resonance imaging using gadolinium contrast. Preliminary studies have introduced the use of controlled…
Variability of Resting Carbon Dioxide Tension in Patients with Intracranial Steno-occlusive Disease Open
Introduction Controlling the partial pressure of carbon dioxide (PaCO2) is an important consideration in patients with intracranial steno-occlusive disease to avoid reductions in critical perfusion from vasoconstriction due to hypocapnia, …
View article: Transient deoxyhemoglobin formation as a contrast for perfusion MRI studies in patients with brain tumors: a feasibility study
Transient deoxyhemoglobin formation as a contrast for perfusion MRI studies in patients with brain tumors: a feasibility study Open
Background: Transient hypoxia-induced deoxyhemoglobin (dOHb) has recently been shown to represent a comparable contrast to gadolinium-based contrast agents for generating resting perfusion measures in healthy subjects. Here, we investigate…
Cerebral perfusion metrics calculated directly, model-free, from a hypoxia-induced step change in deoxyhemoglobin Open
Dynamic susceptibility contrast (DSC) perfusion MRI measures blood flow metrics via application of a BOLD pulse sequence during transit of a gadolinium-based contrast agent (GBCA), We have previously shown that can also be performed using …
The Choroid Plexus as an Alternative Locus for the Identification of the Arterial Input Function for Calculating Cerebral Perfusion Metrics Using MRI Open
The choroid plexus provides an alternative location from which an arterial input function may be sampled when a suitable measure over an MCA is not available.
Assessment of Cerebrovascular Reactivity Using <span>CO<sub>2</sub>‐BOLD MRI</span>: A 15‐Year, Single Center Experience Open
Background Cerebrovascular reactivity (CVR) is a measure of the change in cerebral blood flow (CBF) in response to a vasoactive challenge. It is a useful indicator of the brain's vascular health. Purpose To evaluate the factors that influe…
Assessing Perfusion in Steno-Occlusive Cerebrovascular Disease Using Transient Hypoxia-Induced Deoxyhemoglobin as a Dynamic Susceptibility Contrast Agent Open
Cerebral perfusion metrics generated with noninvasive transient hypoxia-induced changes in deoxyhemoglobin are very similar to those generated using a gadolinium-based contrast agent in patients with cerebrovascular steno-occlusive disease.
Determining the effects of elevated partial pressure of oxygen on hypercapnia-induced cerebrovascular reactivity Open
Evaluation of cerebrovascular reactivity (CVR) to hypo- and hypercapnia is a valuable test for the assessment of vasodilatory reserve. While hypercapnia-induced CVR testing is usually performed at normoxia, mild hyperoxia may increase tole…
Convolutional Neural Networks to Assess Steno-Occlusive Disease Using Cerebrovascular Reactivity Open
Cerebrovascular Reactivity (CVR) is a provocative test used with Blood oxygenation level-dependent (BOLD) Magnetic Resonance Imaging (MRI) studies, where a vasoactive stimulus is applied and the corresponding changes in the cerebral blood …
Transfer function analysis assesses resting cerebral perfusion metrics using hypoxia-induced deoxyhemoglobin as a contrast agent Open
Introduction: Use of contrast in determining hemodynamic measures requires the deconvolution of an arterial input function (AIF) selected over a voxel in the middle cerebral artery to calculate voxel wise perfusion metrics. Transfer functi…
DSC MRI in the human brain using deoxyhemoglobin and gadolinium—Simulations and validations at 3T Open
Introduction Dynamic susceptibility contrast (DSC) MRI allows clinicians to determine perfusion parameters in the brain, such as cerebral blood flow, cerebral blood volume, and mean transit time. To enable quantification, susceptibility ch…
Investigations of hypoxia‐induced deoxyhemoglobin as a contrast agent for cerebral perfusion imaging Open
The assessment of resting perfusion measures (mean transit time, cerebral blood flow, and cerebral blood volume) with magnetic resonance imaging currently requires the presence of a susceptibility contrast agent such as gadolinium. Here, w…
Assessment of cerebrovascular function in patients with sickle cell disease using transfer function analysis Open
In patients with sickle cell disease (SCD), the delivery of oxygen to the brain is compromised by anemia, abnormal rheology, and steno‐occlusive vascular disease. Successful compensation depends on an increase in oxygen supply such as that…
Sickle cell cerebrovascular reactivity to a CO2 stimulus: Too little, too slow Open
Background: Despite increased cerebral blood flow (CBF), cerebral infarcts occur in patients with sickle cell disease (SCD). This suggests increased CBF does not meet metabolic demand possibly due to compromised cerebral vasodilatory respo…
Perfusion Quantification in the Human Brain Using DSC MRI – Simulations and Validations at 3T Open
Gadolinium (Gd) and deoxyhemoglobin (dOHb) are paramagnetic contrast agents capable of inducing changes in T 2 *-weighted MRI signal, utilized in dynamic susceptibility contrast (DSC) MRI. With multiple contrast agents and analysis choices…
Assessing Cerebrovascular Resistance in Patients With Sickle Cell Disease Open
In patients with sickle cell disease (SCD) the delivery of oxygen to the brain is compromised by anemia, abnormal rheology, and steno-occlusive vascular disease. Meeting demands for oxygen delivery requires compensatory features of brain p…
Cerebral perfusion imaging: Hypoxia-induced deoxyhemoglobin or gadolinium? Open
Assessment of resting cerebrovascular perfusion measures (mean transit time, cerebral blood flow and cerebral blood volume) with magnetic resonance imaging currently requires the intravascular injection of the dynamic susceptibility contra…
Cerebrovascular reactivity changes in acute concussion: a controlled cohort study Open
Concussion is associated with patient-specific abnormalities in BOLD cerebrovascular responsiveness that occur in the setting of normal global CVR. This study demonstrates that the measurement of CVR using BOLD MRI and precise CO2 control …
Measuring Cerebrovascular Reactivity: Sixteen Avoidable Pitfalls Open
An increase in arterial PCO 2 is the most common stressor used to increase cerebral blood flow for assessing cerebral vascular reactivity (CVR). That CO 2 is readily obtained, inexpensive, easy to administer, and safe to inhale belies the …
Normal BOLD Response to a Step CO2 Stimulus After Correction for Partial Volume Averaging Open
Cerebrovascular reactivity (CVR) is defined as the change in cerebral blood flow induced by a change in a vasoactive stimulus. CVR using BOLD MRI in combination with changes in end-tidal CO 2 is a very useful method for assessing vascular …
The Effect of CO2 on Resting-State Functional Connectivity: Isocapnia vs. Poikilocapnia Open
The normal variability in breath size and frequency results in breath-to-breath variability of end-tidal PCO 2 (P ET CO 2 ), the measured variable, and arterial partial pressure of carbon dioxide (PaCO 2 ), the independent variable affecti…
The Reproducibility of Cerebrovascular Reactivity Across MRI Scanners Open
Cerebrovascular reactivity (CVR) is defined as the ratio of the cerebral blood flow (CBF) response to an increase in a vasoactive stimulus. We used changes in blood oxygenation level-dependent (BOLD) MRI as surrogates for changes of CBF, a…
The value of a shorter-delay arterial spin labeling protocol for detecting cerebrovascular impairment Open
In conclusion, our study reveals and highlights the value of a shorter-PLD ASL protocol, which is able to reflect CVR impairment. At the same time, we offer a better understanding of the relationship between BOLD CVR and CBF obtained from …
L-arginine effects on cerebrovascular reactivity, perfusion and neurovascular coupling in MELAS (mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes) syndrome Open
NCT01603446.
Cerebrovascular Reactivity Assays Collateral Function in Carotid Stenosis Open
In patients with carotid artery stenosis (CAS), the risk of stroke, its severity, and response to revascularization are strongly related to the availability of collateral blood flow. Unfortunately, there is poor agreement between observers…