[1] Yale Univ, Sch Med, Dept Neurosurg, New Haven, CT 06510 USA
[2] Quinnipiac Univ, Frank H Netter Sch Med, North Haven, CT USA
[3] Univ Geneva, Med Ctr, Fac Med, Dept Clin Neurosci,Neurosurg Div, CH-1211 Geneva, Switzerland
[4] Yale Univ, Sch Med, Dept Radiol & Biomed Imaging, New Haven, CT 06510 USA