Imaging Cerebral Blood Flow in the Cognitively Normal Aging Brain with Arterial Spin Labeling: Implications for Imaging of Neurodegenerative Disease

To authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1552-6569.2008.00277.x Byline: Charles Lee (1), Oscar L. Lopez (1), James T. Becker (1), Cyrus Raji (1), Weiying Dai (1), Lewis H. Kuller (1), H. Michael Gach (1) Keywords: Arterial spin labeling; MRI; normal aging brain; neurodegenerative disease; cerebral perfusion; cerebral blood flow Abstract: ABSTRACT INTRODUCTION Arterial spin labeling (ASL) is a safe, noninvasive imaging method for evaluating cerebral blood flow (rCBF). The purpose of this article is to present ASL imaging features of 38 elderly cognitively normals (CN) with their rCBF values and an averaged profile of targeted anatomic regions rCBF values. METHODS: Thirty-eight CN underwent MR imaging especially ASL with voxel morphometric techniques fusing the MR anatomical and ASL images to a standard reference brain (colin27). The ASL images were fused to echo planar images, which were then coregistered to high-resolution anatomical SPGR images. rCBF was calculated per region of interest using a modified continuous arterial spin labeling (CASL) convolutional method. Anatomical regions were selected and identified by the Talairach atlas in SPM2. RESULTS We identified areas of decreased and increased perfusion (compared to the averaged rCBF of all 38 CN) corresponding to decreased and increased quantified rCBF. The most common sites for decreased perfusion were precuneus (53%), superior temporal (48%), and orbitofrontal (37%), and for increased perfusion the caudate (39%), posterior cingulate (34%), anterior cingulate (32%), and amygdala (32%). CONCLUSION There are regional variations in rCBF both increased and decreased with the posterior cingulate and precuneus cortex showing the highest averaged values and signal intensity (bright spots). These variations represent the normal profile of a CN elderly brain, with higher perfusion in areas associated with cognition, memory, and behavior. It is necessary to understand these normal variations in order to determine if there are perfusion changes in ASL detected in neurodegenerative disorders such as Alzheimer's disease. Author Affiliation: (1)From the Department of Radiology, Neuroradiology Division (CL, CR, HMG); Department of Neurology (OLL); Department of Psychiatry (JTB, CR); Department of Computer Science (now located at Beth Israel Hospital) (WD); Department of Epidemiology (LHK); and Nevada Cancer Center, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania (HMG). Article History: Acceptance: Received October 25, 2007, and in revised form April 14, 2008. Accepted for publication May 19, 2008. Article note: Correspondence: Address correspondence to Charles Lee, MD, UPMC Presbyterian D-132, 200 Lothrop Street, Pittsburgh, PA 15213-2582. E-mail: leec@upmc.edu.