Clinical Research Studies
High Resolution and Functional MRI Assessment of Intracranial Atherosclerotic Plaque
Intracranial atherosclerotic disease (ICAD) accounts for 7-10% of cute ischemic stroke with a substantial risk of recurrent stroke in a setting of severe intracranial stenosis, approaching 12-25% over 1-2 years despi…
Intracranial atherosclerotic disease (ICAD) accounts for 7-10% of cute ischemic stroke with a substantial risk of recurrent stroke in a setting of severe intracranial stenosis, approaching 12-25% over 1-2 years despite medical management. However, a risk stratification scheme is not available to identify this susceptible population for targeted treatment trials when intervention with more aggressive medical management and/or endovascular angioplasty/stenting could limit complications of ischemic stroke. The unmet need that we plan to address is to develop and study MR imaging modalities that may characterize vulnerable inflammatory and/or hemodynamically significant intracranial plaques, stratifying the mechanisms and potential predictors of primary/recurrent ischemic stroke in ICAD. Recently, we have identified unique intracranial plaque characteristics as well as hemodynamic parameters using quantitative MR perfusion techniques to stage cerebrovascular reserve failure that are associated with symptomatic intracranial stenoses. We propose a prospective study to recruit asymptomatic and symptomatic patients with severe ICAD and longitudinally assess them with a comprehensive and novel MRI protocol: high resolution 3T MR imaging, ferumoxytol molecular imaging, dynamic contrast enhanced (DCE) MRI to quantify the transfer constant (Ktrans) of contrast plaque permeability, and dynamic susceptibility contrast (DSC) MR perfusion weighted imaging (MRPWI) using the quantitative SCALE-PWI sequence. Our study hypothesis is that high resolution T1 plaque enhancement, T1/T2 plaque hemorrhage, early ferumoxytol uptake as a marker of macrophage infiltration/inflammation, intraplaque Ktrans permeability, and/or altered qCBF/qCBV perfusion based parameters with vascular territory analysis will assist in stratifying patient risk for thromboembolic versus hypoperfusion related ischemic complications respectively. This project aims to identify specific qualitative and quantitative thresholds with advanced high resolution, molecular, and functional MRI techniques that can be correlated to clinical presentations (asymptomatic, symptomatic, recurrent symptomatic), DWI infarct distributions (perforator, thromboembolic, hypoperfusion related infarcts), inflammatory blood markers, and clinical/imaging outcomes to inform an understanding of differential stroke mechanisms and to improve the selection of high risk ICAD patients who may be susceptible to primary or recurrent ischemic stroke despite aggressive medical management.
1- Severe ICAD>70% confirmed by SOC CTA/MRA/DSA using SAMMPRIS criteria2
2- AGE 30-80 YEARS
3- At least one segment of
a) supraclinoid ICA,
b) A1-A2 ACA,
c) M1-M2 MCA,
d) intracranial vertebral-basilar artery
e) P1-P2 PCA
4- Age 30-80 years
5- Symptomatic patients defined as an association between the intracranial stenosis and hemodynamic impairment of the corresponding vascular territory, based on either neurological exam (TIAs/stroke) and/or acute/subacute infarcts documented on MR-DWI
1- Contraindications to MRI-Fill safety questionnaire day before MRI/Call to ask
2- GFR70% cervical carotid or vertebral artery proximal stenosis, or tandem intracranial stenoses,
5- Impaired liver function
Functional MRI Study of Transcranial Electrical Stimulation in Chronic Tinnitus
Why is this study being done?
Many people hear a ringing or buzzing in their ears, called tinnitus. This study uses brain scans (MRI) to understand how painless electrical currents applied to the head, a method c…
Why is this study being done?
Many people hear a ringing or buzzing in their ears, called tinnitus. This study uses brain scans (MRI) to understand how painless electrical currents applied to the head, a method called "transcranial electrical stimulation," might change the way the brain works to relieve tinnitus.What's involved in this study?
This study involves one 5-hour visit to Northwestern's Chicago Streeterville campus. You may also have 5 more visits, which will take one hour (or less). Whether you have 1 or 6 visits will depend on your availability, staff availability, and other factors like our funding.
During the first visit, you'll answer questionnaires about your health history, take a brief hearing test, and have an MRI. During the MRI, you will have active and inactive tES.
If you have 5 more visits, you'll have tES applied to your head for 20 minutes during the first visit and on the next 4 consecutive days. You may have active tES during all 5 visits, or inactive "sham" tES during all 5 visits. At the last visit, you'll have a short MRI. Two weeks later, we'll tell you whether you had active or inactive tES. If you had inactive tES, you can come back in for five sessions of active tES, if you'd like.
In past studies, about half of people noticed that tinnitus was less intrusive right after tES, but these effects did not seem to last long term. Your tinnitus symptoms may or may not decrease during this study. *Note that we are unable to compensate volunteers for travel expenses, and we are not encouraging volunteers outside the Chicago area to participate in this study.
Who can participate in this study?
If you have had tinnitus for 1 year or longer, and have spoken with a physician or audiologist about your symptoms, you may be eligible to volunteer for our study. Other criteria include:
What does tES feel like?
People describe tES as a light tingling or itching on their skin that is not painful. For most people, this feeling decreases or goes away after ~30 seconds, and some don’t feel tES at all. Remember that we can stop tES right away if you decide to stop for any reason. tES uses sponges covered in gel to prevent irritation, which can be removed with water.
I'd like to volunteer for this study. What's next?
If you're interested in volunteering for this study, please contact the study team via email or phone to schedule prescreening. During prescreening, we will review questions about your health history over phone or secure website to determine whether you’re eligible for this study. We will also talk more about the study, and answer your questions.
inmri at northwestern dot edu
(312) 694 2966