Measurement of cerebral perfusion with arterial spin labeling: Part 2. Applications
Arterial spin labeling (ASL) uses magnetic resonance imaging methods to measure cerebral blood flow (CBF) non-invasively. ASL CBF validly localizes brain function and may be especially useful for studies where the time frame of behavioral change is more than a few minutes, such as in longitudinal and treatment studies. ASL measures of cerebral perfusion are highly accurate in detecting lesion laterality in temporal lobe epilepsy, stenotic-occlusive disease, and brain tumors. Among lesioned patients, ASL CBF has excellent concurrent validity when correlated with CBF measured by Positron Emission Tomography or with dynamic susceptibility-weighted magnetic resonance. ASL CBF can predict tumor grading in vivo and can predict six-month response to the surgical treatment of brain tumors. ASL's capability to selectively and non-invasively tag flow in major vessels may refine the monitoring of treatment of cerebrovascular disease and brain tumors. Conclusions about the utility of ASL are limited by the small sample sizes of the studies currently in the literature and by the uncertainty caused by the effect of brain disease on transit times of the magnetic tag. As the method evolves, ASL techniques will likely become more widely used in clinical research and practice. (JINS, 2007, 13, 526–538.)(Received March 30 2006)
(Revised November 15 2006)
(Accepted November 16 2006)
Key Words: Magnetic resonance imaging; Functional; Regional blood flow; Brain mapping; Cerebral stroke; Brain tumors; Epileptic seizures.
c1 Correspondence and reprint requests to: Gregory G. Brown, Ph.D., Psychology Service (MC 116B), VA San Diego Healthcare System, 3350 La Jolla Village Drive, La Jolla, CA, 92161. E-mail: [email protected]