Measuring Cerebral Blood Flow Using Pseudo-continuous Arterial Spin Labeling Perfusion Magnetic Resonance Imaging
Condition: Traumatic Brain Injury; Multiple Sclerosis; Alzheimer's Disease; Tumor
MeSH terms: Multiple Sclerosis; Alzheimer Disease; Brain Injuries; Brain Injuries, Traumatic
Study type: Interventional

Summary: 
      This study will test a new MRI sequence that measures cerebral blood flow (CBF). Because this
      technique for measuring CBF is new, there is little information on what the normal values for
      different regions of the brain should be. Information from the study will be used to
      establish normative CBF values for the brain, improving the reliable use of this technique
      for the diagnosis of brain injury or disease.
    

Detailed description: 
      Cerebral blood flow (CBF) represents an important physiological parameter for the diagnosis
      and management of multiple brain disorders. The clinical need for CBF measurements is further
      complicated by the desire to have a non-invasive method with high temporal resolution that
      can measure CBF over a wide range of blood flows and in a wide range of patients. Numerous
      techniques are available to measure CBF. Nuclear medicine approaches, such as single positron
      emission computed tomography (SPECT) and positron emission tomography (PET) rely on
      radioisotopes which can be problematic in the pediatric population. In contrast, MRI-based
      methods are non-invasive and the CBF information can be obtained in conjunction with other
      MRI techniques (i.e. diffusion weighted imaging or spectroscopy) which allows for a combined
      longitudinal assessment of CBF, morphology, and metabolism, to provide a more complete
      understanding of the developing pathophysiological mechanisms.

      Arterial spin labeling (ASL) perfusion imaging uses arterial blood water as an endogenous
      diffusible tracer where radiofrequency (RF) pulses magnetically label the moving spins in
      flowing blood without the use of a contrast agent. After a time delay allowing for the
      magnetically labeled blow to flow into the brain, "labeled" images are acquired. Separate
      control images are also acquired, without labeling and the difference between the two sets of
      imaged provides a measure of perfusion. Since gadolinium-based contrast agents are not
      required, the ASL perfusion technique is completely non-invasive. In addition, ASL techniques
      are insensitive to blood-brain barrier permeability changes, which can occur after strokes or
      with tumors.

      Because gadolinium-based contrast is not used, the ASL technique has an inherently lower
      sensitivity than DSC-PWI. To date, there are a number of commercially available ASL
      techniques that differ in their labeling schemes, which has contributed to the difficulty in
      obtaining consistent results across different patient populations (pediatric, elderly,
      stroke, tumors). A number of recent reports using pseudo-continuous ASL (pCASL) have been
      published and show increased reliability across different patient populations. Moreover, a
      recent consensus statement published by the International Society of Magnetic Resonance in
      Medicine Perfusion Study Group recommends the use of pCASL labeling strategies for clinical
      applications.

      The objectives of this study is to determine the accuracy and reliability of a newly
      developed pCASL sequence and post-processing software across multiple patient populations
      (neonate to elderly) and pathological processes.
    

Intervention name(s): Magnetic Resonance Imaging
Intervention type(s): Device
Intervention description(s): All participants will have be given a MRI using a pseudo-continuous arterial spin labeling perfusion sequence.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science