[1] Harvard Univ, Beth Israel Deaconess Med Ctr, Sch Med, Dept Radiol, Boston, MA 02215 USA
[2] Univ Sao Paulo, Fac Med, Hosp Clin, Inst Radiol, BR-09500900 Sao Paulo, Brazil
[3] Albert Einstein Hosp, Dept Radiol, Inst Irsaelita Ensino & Peaquisa Albert Einstein, Sao Paulo, Brazil
[4] Harvard Univ, Beth Israel Deaconess Med Ctr, Sch Med, Dept Cardiothorac Surg, Boston, MA 02215 USA