Neuro Vascular Brain Imaging Laboratory
The purpose of our lab is to advance the understanding, treatment, and prevention of neurologic disease by developing, implementing and validating novel imaging techniques. Although the techniques developed are often applicable to a host of neurologic conditions, there is a particular focus on using magnetic resonance imaging (MRI) in vascular brain disease. Although our techniques are primarily aimed at the management of stroke, they are likely to have a broad impact, improving imaging of patients with brain tumors, Alzheimer’s disease, multiple sclerosis and traumatic brain injury.
The driving concepts behind our innovations are:
- The current approach to how MRI scans are used in health care is inadequate due to a lack of quantification. Replacing or complementing qualitative assessments with quantitative assessments facilitates standardization, can be used to generate predictive models, and is a key component in any well-designed clinical trial.
- There is substantial information in the MRI scans that we are currently using in health care that is not being extracted. By developing new methods for processing images we hope to discover unrecognized measures of disease states to help guide our diagnosis, treatment, and prevention.
- MRI has become a household word and is widely recognized as the definitive technique for imaging the brain. However, despite having revolutionized medicine, MRI is still in its infancy and we must continue to pursue new ways to use MRI to understand physiologic and pathologic processes.
Detecting Damage to the Blood-Brain Barrier of Stroke Patients
Tissue plasminogen activator (tPA), also referred to as the “clot busting” medication, has revolutionized the treatment of acute ischemic stroke. However this medication has a potentially fatal side effect of bleeding in the brain. This complication of tPA has limited the number of patients who are eligible to receive this drug. Even in patients who meet the strict FDA guidelines for use of tPA, approximately 6% of patients will suffer significant bleeding.
Dr. Richard Leigh has developed a novel way to estimate the risk of bleeding stroke patients who are being considered for tPA. This technique uses a type of MRI scan that is routinely acquired in stroke patients for other purposes, and detects damage to the blood-brain barrier which is a maker for bleeding risk. Preliminary results indicate that this new imaging technique will be helpful to clinicians when deciding whether to give, or withhold, tPA. This tool has the potential to increase the number of patients that get treated while decreasing the number of complications.
Understanding How Decreased Blood Flow Affects the Brain Using pH-Weighted MRI
When a blood vessel that supplies the brain is blocked for a prolonged period of time, the consequence is often a stroke. Current MRI techniques are able to measure the blood flow to the brain, however it is difficult to know if such an interruption of blood flow is severe enough to cause injury. Animal studies indicate that brain tissue that is not getting enough blood flow will start to generate lactic acid, which makes it more acidic (lower pH). Thus a method to detect changes in pH of the brain would likely be useful to doctors treating stroke patients.
Researchers at the F. M. Kirby Center designed a new MRI technique to solve this challenge. Lead by Dr. Peter van Zijl, this group developed a method for imaging the pH (acid-base balance) of the brain. In an effort to advance the treatment of acute stroke patients, Dr. Richard Leigh has teamed up with the basic scientists at the F.M. Kirby Center in a translational research project to bring this new pH-weighted imaging into clinical use.