[1] Univ New Mexico, Hlth Sci Ctr, Dept Radiol, 1 Univ New Mexico,MSC 10 5530, Albuquerque, NM 87131 USA
[2] Univ Kentucky, Dept Pathol & Lab Med, Lexington, KY USA
[3] Univ New Mexico, Dept Neurol, Albuquerque, NM 87131 USA
[4] Univ Calif San Francisco, Ctr Cerebrovasc Res, Dept Anesthesia & Perioperat Care, San Francisco, CA 94143 USA