Arterial Spin Labeling MRI Perfusion
by Dr. Jeffrey M. Pollock, MD
How it works: Arterial Spin Labeling or ASL is a non-invasive method of measuring cerebral blood flow, or blood flow in the brain. The technique does not require intravenous contrast and can be performed on patients of all ages. The scanner creates an image showing relative changes in cerebral perfusion. Additional techniques can be performed that can show actual flow over time (Multiphase ASL). These techniques are most beneficial to patients with vascular stenosis, stroke, arteriovenous malformations, and tumors.
Equipment: Our MRI suite uses the latest Phillips 3.0 tesla magnet coupled with a state of the art Phillips Clinical ASL software package. Processing is performed automatically as soon as the scan is completed and images are available for immediate interpretation.
Benefits: ASL is non-invasive so it can be performed on any routine brain MRI on any patient regardless of intravenous access, contrast allergy, or renal status. In young patients ASL is the optimal technique because the child’s veins can be too small to inject a rapid contrast bolus needed for other forms of MRI perfusion (DSC LINK). ASL can show perfusion abnormalities when all other MRI sequences appear normal. The best example of this is a patient with a transient ischemic attack or TIA. These patient’s have brief stroke like symptoms, but may have a normal MRI. ASL perfusion can reveal subtle perfusion changes that could allow possible therapeutic interventions to prevent a future stroke.
Exam Preparation: The technologist will interview you prior to scan to make sure you have no contraindications to being in the MRI scanner. Patients with braces or other metal near the head or neck may not be suitable for ASL because of the artifacts the metal can cause. Also individuals who have received MRI gadolinium based intravenous contrast within 48 hours of the ASL exam may not be suitable for perfusion imaging because of additional artifacts.
What to expect: ASL alone takes approximately 4-5 minutes of scanner time. The study is done in conjunction with routine anatomic imaging.
Jeffrey M. Pollock, MD
Associate Professor of Neuroradiology
- Pollock JM, Deibler AR, West TG, Burdette JH, Kraft RA, Maldjian JA. Arterial Spin-Labeled Magnetic Resonance Imaging in Hyperperfused Seizure Focus: a Case Report. J Comput Assist Tomogr. 2008 March/April;32(2):291-292
- Deibler AR, Pollock JM, Kraft RA, Tan H, Burdette JH, Maldjian JA. Arterial spin-labeling in routine clinical practice, part 1: technique and artifacts. AJNR Am J Neuroradiol 2008 Aug;29(7):1228-34.
- Deibler AR, Pollock JM, Kraft RA, Tan H, Burdette JH, Maldjian JA. Arterial spin-labeling in routine clinical practice, part 2: hypoperfusion patterns. AJNR Am J Neuroradiol 2008 Aug;29(7):1235-1241
- Pollock JM, Whitlow CT, Deibler AR, Burdette JH, Kraft RA, Tan H, Maldjian JA. Anoxic injury-associated cerebral hyperperfusion identified with arterial spin-labeled MR imaging. AJNR Am J Neuroradiol 2008 Aug;29:1302-1307
- Deibler AR, Pollock JM, Kraft RA, Tan H, Burdette JH, Maldjian JA. Arterial Spin Labeling in Routine Clinical Practice Part 3: Hyperperfusion Patterns. AJNR Am J Neuroradiol. 2008 Sep;29(8):1428-35
- Pollock JM, Deibler AR, Burdette JH, Kraft RA, Tan H, Evans AB, Maldjian JA. Arterial Spin Labeled MRI in Hyperperfused Migraine Evaluation. AJNR Am J Neuroradiol. 2008 Sep;29(8):1494-7
- Pollock JM, Deibler AR, Whitlow CT, Kraft RA, Tan H, Burdette JH, Maldjian JA. Hypercapnia-Induced Cerebral Hyperperfusion: An Underrecognized Clinical Entity. AJNR Am J Neuroradiol. 2009 Feb;30:378-85
- Pollock JM, Whitlow CT, Kraft RA, Tan H, Burdette JH, Maldjian JA. Pulsed Arterial Spin Labeled MRI Evaluation of Tuberous Sclerosis. Am J Neuroradiol. 2009 Apr;30(4):815-2
- Pollock JM, Whitlow CT, Deibler AR, Burdette JH, Kraft RA, Tan H, Maldjian JA. PASL Clinical Applications. MRI Clinics of North America. 2009 May;17(2):315-38.
- Tan H, Maldjian JA, Pollock JM, Burdette JH, Yang LY, Deibler AR, Kraft RA. A Fast, Effective Filtering Method for Improving Clinical Pulsed Arterial Spin Labeling MRI. J Magn Reson Imaging. 2009 2009 May;29(5):1134-9