
Dr. David J. Mikulis
Dr. David Mikulis is Full Professor and Director of the Functional Neuroimaging Research Lab in the Joint Department of Medical Imaging at the University Health Network and the University of Toronto. The primary emphasis of this work has been translational research focusing on the application of novel imaging methods into the clinical environment.
Dr. Mikulis established one of the first fMRI labs in Canada in 1993 and is currently involved in developing advanced neurovascular imaging methods with major program arms including: 1) quantitative measurement and clinical application of cerebrovascular reactivity (CVR) metrics leading to the development of “the brain stress test” (analogous to the cardiac stress test) that assess the effectiveness of the cerebral circulatory system in meeting the metabolic needs of the brain; 2) high resolution and functional imaging of intra- and extra-cranial blood vessel walls that improves diagnostic accuracy for assessing diseases that directly affect blood vessels; 3) discovery of a new method for measuring brain blood flow that does not require injection of contrast agents.
Research in the above areas has improved assessment of the structure, function, and performance of the vascular system in health and disease. These capabilities have further defined the important roles that abnormal vascular performance measures have in the pathophysiology of a number of conditions including for example Alzheimer’s and vascular dementias, and in improving diagnostic accuracy of acute concussion.
Translation of these methods has been achieved locally, nationally, and internationally confirming the importance of these tools in research and clinical settings.
- Convolutional Neural Networks to Assess Steno-Occlusive Disease Using Cerebrovascular Reactivity
Cerebrovascular Reactivity (CVR) is a provocative test used with Blood oxygenation level-dependent (BOLD) Magnetic Resonance Imaging (MRI) studies, […]
- Determining the effects of elevated partial pressure of oxygen on hypercapnia-induced cerebrovascular reactivity
Evaluation of cerebrovascular reactivity (CVR) to hypo- and hypercapnia is a valuable test for the assessment of vasodilatory reserve. While […]
- Evaluating the influence of altered cerebral hemodynamics on cognitive performance in asymptomatic carotid artery stenosis: A systematic review
CONCLUSIONS: This review lends support to the claim that cognitive impairment, likely the result of impaired cerebral hemodynamics, is an […]
- Heterogeneous motor BOLD-fMRI responses in brain areas exhibiting negative BOLD cerebrovascular reactivity indicate that steal phenomenon does not always result from exhausted cerebrovascular reserve capacity
CONCLUSION: We show that the presence of negative BOLD-CVR responses to CO(2) is associated with heterogeneous motor task-based BOLD-fMRI signal […]
- A dual-center validation of the PIRAMD scoring system for assessing the severity of ischemic Moyamoya disease
CONCLUSIONS: Our multicentric validation of the recently published PIRAMD scoring system was highly effective in rating the severity of ischemic […]
- Transfer function analysis assesses resting cerebral perfusion metrics using hypoxia-induced deoxyhemoglobin as a contrast agent
Introduction: Use of contrast in determining hemodynamic measures requires the deconvolution of an arterial input function (AIF) selected over a […]
- Cerebrovascular Reactivity and Concussion
Cerebrovascular reactivity (CVR) reflects the change in cerebral blood flow in response to vasodilatory stimuli enabling assessment of the health of […]
- Should trigeminal neuralgia be considered a clinically isolated syndrome?
The association between trigeminal neuralgia (TN) and multiple sclerosis (MS) is well established. Many MS patients with TN have magnetic resonance […]
- Brain Stress Test for Assessing Risk for Hemodynamic Stroke
CONCLUSION: Our study confirms that CO(2)-BOLD MRI CVR can be used as a brain stress test for the assessment of cerebrovascular reserve. Impaired CVR […]
- Angiopep-2, an MRI Biomarker, Dynamically Monitors Amyloid Deposition in Early Alzheimer's Disease
The reliable and dynamic detection of amyloid β-protein (Aβ) deposition using imaging technology is necessary for preclinical Alzheimer's disease […]
- Longitudinal Patterns of Functional Connectivity in Moderate-to-Severe Traumatic Brain Injury
Longitudinal neuroimaging studies aid our understanding of recovery mechanisms in moderate-to-severe traumatic brain injury (TBI); however, there is […]
- Investigations of hypoxia-induced deoxyhemoglobin as a contrast agent for cerebral perfusion imaging
The assessment of resting perfusion measures (mean transit time, cerebral blood flow, and cerebral blood volume) with magnetic resonance imaging […]
- Assessment of cerebrovascular function in patients with sickle cell disease using transfer function analysis
In patients with sickle cell disease (SCD), the delivery of oxygen to the brain is compromised by anemia, abnormal rheology, and steno-occlusive […]
- Quantifying cerebral blood arrival times using hypoxia-mediated arterial BOLD contrast
Cerebral blood arrival and tissue transit times are sensitive measures of the efficiency of tissue perfusion and can provide clinically meaningful […]
- Functional brain activity constrained by structural connectivity reveals cohort-specific features for serum neurofilament light chain
CONCLUSIONS: Our results suggest that GSP-derived brain features may be included in models of baseline variance when evaluating NfL as a biomarker of […]
- Assessing Cerebrovascular Resistance in Patients With Sickle Cell Disease
In patients with sickle cell disease (SCD) the delivery of oxygen to the brain is compromised by anemia, abnormal rheology, and steno-occlusive […]
- Voxel-based morphometry and a deep learning model for the diagnosis of early Alzheimer's disease based on cerebral gray matter changes
This study aimed to analyse cerebral grey matter changes in mild cognitive impairment (MCI) using voxel-based morphometry and to diagnose early […]
- Does breathing pattern affect cerebrovascular reactivity?
NEW FINDINGS: What is the central question of this study? Is cerebrovascular reactivity affected by isocapnic changes in breathing pattern? What is […]
- Cerebrovascular reactivity changes in acute concussion: a controlled cohort study
CONCLUSIONS: Concussion is associated with patient-specific abnormalities in BOLD cerebrovascular responsiveness that occur in the setting of normal […]
- Current Concepts in Intracranial Interstitial Fluid Transport and the Glymphatic System: Part II-Imaging Techniques and Clinical Applications
The glymphatic system is a recently discovered network unique to the central nervous system that allows for dynamic exchange of interstitial fluid […]
- Perfusion MRI using endogenous deoxyhemoglobin as a contrast agent: Preliminary data
CONCLUSION: This study demonstrates that induced abrupt changes in deoxyhemoglobin can function as a noninvasive vascular contrast agent that may be […]
- Current Concepts in Intracranial Interstitial Fluid Transport and the Glymphatic System: Part I-Anatomy and Physiology
Normal physiologic function of organs requires a circulation of interstitial fluid to deliver nutrients and clear cellular waste products. Lymphatic […]
- Measuring Cerebrovascular Reactivity: Sixteen Avoidable Pitfalls
An increase in arterial PCO(2) is the most common stressor used to increase cerebral blood flow for assessing cerebral vascular reactivity (CVR). […]
- Normal BOLD Response to a Step CO2 Stimulus After Correction for Partial Volume Averaging
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 […]
- Progressive Neurodegeneration Across Chronic Stages of Severe Traumatic Brain Injury
CONCLUSION: Localized yet progressive decline emphasizes the necessity of developing interventions to offset degeneration and improve long-term […]
- Regional brain morphology predicts pain relief in trigeminal neuralgia
CONCLUSIONS: Our findings support the use of machine learning techniques in subsequent investigations of chronic neuropathic pain. Furthermore, our […]
- The Effect of CO2 on Resting-State Functional Connectivity: Isocapnia vs. Poikilocapnia
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, […]
- Parkinsonism as a Sequela of SARS-CoV-2 Infection: Pure Hypoxic Injury or Additional COVID-19-Related Response?
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- The Reproducibility of Cerebrovascular Reactivity Across MRI Scanners
Cerebrovascular reactivity (CVR) is defined as the ratio of the cerebral blood flow (CBF) response to an increase in a vasoactive stimulus. We used […]
- Cerebrovascular Reactivity: Purpose, Optimizing Methods, and Limitations to Interpretation - A Personal 20-Year Odyssey of (Re)searching
The brain is a neurovascular organ. A stimulus-response approach is effective in interrogating the physiology of its vasculature. Ideally, the […]