[1] Massachusetts Gen Hosp, Harvard Med Sch, Dept Radiol, Boston, MA USA
[2] Massachusetts Gen Hosp, Dept Anesthesiol Crit Care & Pain Med, Boston, MA USA
[3] Harvard Med Sch, Massachusetts Eye & Ear Infirm, Dept Anesthesiol, 243 Charles St, Boston, MA 02114 USA
[4] Univ Miami, Univ Miami Hlth Syst, Miller Sch Med, Dept Anesthesiol Perioperat Med & Pain Management, Miami, FL USA