TY - JOUR T1 - Dr. Leighton Mark was invited to comment on this issue. JF - American Journal of Neuroradiology JO - Am. J. Neuroradiol. SP - 982 LP - 984 VL - 21 IS - 5 AU - Leighton P. Mark Y1 - 2000/05/01 UR - http://www.ajnr.org/content/21/5/982.3.abstract N2 - ER -