Assessing Brain Injury Using Portable Magnetic Resonance Imaging (MRI)

Study Overview
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Brief Summary
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This study aims to assess the feasibility of assessing acute brain injury using a portable low field MRI in patients on ECMO.

Detailed Description
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Extracorporeal membrane oxygenation (ECMO) is a life-saving therapy increasingly used in patients with refractory cardiopulmonary failure. The Extracorporeal Life Support Organization (ELSO) registry recently reported a 58% survival rate among patients who receive ECMO support, showing a significant mortality benefit in patients who would have not survived without ECMO. However, acute brain injury (ABI) is common in patients with ECMO support and leads to devastating consequences with significant morbidity and mortality. The mortality increases more than two-fold when ABI is present for both venoarterial (VA) and venovenous (VV) ECMO patients. The poor prognosis of ABI and neurological complications would suggest potential benefit from stringent and possibly even protocolized neurological monitoring to prevent or minimize further harm. This is particularly important as recent evidence promotes extracorporeal cardiopulmonary resuscitation (ECPR) as a rescue therapy for patients suffering from cardiac arrest of potentially reversible etiology. As clinical experience accumulates and ECPR becomes more widely used, neurological monitoring for complications and prognostication will be imperative for optimizing patient outcomes. Although standardized neurological monitoring improves the detection of ABI, timely diagnosis and management for ABI in patients with ECMO support is still challenging due to the difficulty, impracticality, and danger of transporting ECMO patients to a CT scanner. Often, ECMO patients are unable to be transported to radiology suites because of the patients' persistent cardiopulmonary instability with multiple vasopressor requirements. In addition, even if head CT is performed in these patients, it is limited by poor sensitivity for detecting acute ischemic brain injury. Early neuroimaging is a key neuromonitoring aspect in the clinical evaluation of ABI. However, conventional magnetic resonance imaging (MRI) systems operate at high magnetic field strengths (1.5-3T) that require strict, access-controlled environments. Thus, limited access to timely brain scan with images of sufficient quality remains a significant barrier to effectively monitoring the occurrence and progression of ABI in ECMO. Recent advances in low-field and portable MRI technology have enabled the acquisition of clinically meaningful imaging in the presence of ferromagnetic materials. A very low magnetic field strength, 64 magnetization transfer (mT), approximately 1/23 the field strength of a conventional MRI) provides a 5 Gauss line (safety zone) that is only about 2.5 feet from the center of the scanner. In a previous report, researchers were able to demonstrate the feasibility of a low-field, portable MRI in complex clinical care settings, such as intensive care units, without any adverse events or complications. In addition to reduced projectile motion, the use of low-field MRI may mitigate other safety concerns associated with high-field MRI, such as peripheral nerve stimulation (from gradients), a radiofrequency absorption and heating and acoustic noise. The objective of this study is to assess acute brain injury with low-field, portable MRI of brain in patients with ECMO support. This study will use the Hyperfine portable MRI machine which has FDA 510(k) clearance and is intended for use in intensive care units. The investigators' hypothesis is that low-field, portable MRI can detect ABI in patients with ECMO support, which may decrease the morbidity of patients on ECMO.

Official Title
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Assessing Brain Injury Using Portable Magnetic Resonance Imaging in Patients With Extracorporeal Membrane Oxygenation

Conditions
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Extracorporeal Membrane Oxygenation Complication, Acute Brain Injury

Intervention / Treatment
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* Diagnostic Test: Portable MRI acquisition


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adults age 18 and over Patient supported with extracorporeal membrane oxygenation support (ECMO) Legally authorized representative has provided written informed consent Exclusion Criteria: Patient has a contraindication for MRI such as: Implants such as pacemaker, defibrillator, implanted insulin pump, deep brain stimulator, vagus nerve stimulator, cochlear implant, or programmable shunt MRI incompatible surgical hardware such as staples, screws. ferromagnetic implants such as aneurysm clips, surgical clips, prostheses, cochlear implant artificial hearts or heart valves with steel parts metal fragments shrapnel tattoos near the eye permanent make-up steel implants or other irremovable ferromagnetic objects Patient weight is over 440 lbs (or 200kg) Patient has Intra Aortic Balloon Pump (IABP), Implanted Ventricular Assist Device (VAD), or Percutaneous Ventricular Assist Device Patient is pregnant

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Portable MRI group<br>Patients on ECMO who undergo portable MRI to assess brain injury within 24-48 hours of ECMO initiation | Diagnostic Test: Portable MRI acquisition<br>* Patients on ECMO will undergo a portable MRI of the brain<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Acute brain injury as assessed by head CT scan | compare results of routinely performed head CT scans with results from a low field MRI to determine whether acute brain injury can be assessed using a low field MRI in patients with ECMO support. | 48 hours from ECMO initiation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| prevalence of early acute brain injury as assessed by MRI scan | use interpretations of low field MRI scans to determine the prevalence of early acute brain injury of patients with ECMO support at 24 hours | 24 hours from ECMO initiation | 
| Image Quality | compare image quality of low field MRI scans with the image quality of routinely performed head CT scans to assess the image quality of MR images for infarcts and hemorrhages | 48 hours from ECMO initiation | 
| Impact of early detection as assessed by MRI | assess anticoagulation strategies following low field MRI to determine the impact of early detection of acute brain injury on anticoagulation strategy | 48 hours from ECMO initiation | 
| Association of Transcranial doppler ultrasound with ischemic infarct | measure transcranial doppler ultrasounds and correlate the findings with the results of low field MRI to assess for an association between Transcranial doppler ultrasound (TCD) microembolic signal (MES) and the presence of ischemic infarct on MRI. | 48 hours from ECMO initiation |