PT - JOURNAL ARTICLE AU - Leighton P. Mark TI - Dr. Leighton Mark was invited to comment on this issue. DP - 2000 May 01 TA - American Journal of Neuroradiology PG - 982--984 VI - 21 IP - 5 4099 - http://www.ajnr.org/content/21/5/982.3.short 4100 - http://www.ajnr.org/content/21/5/982.3.full SO - Am. J. Neuroradiol.2000 May 01; 21