[1] Harvard Univ, Sch Med, Brigham & Womens Hosp, Dept Radiol, Boston, MA 02115 USA
[2] Harvard Univ, Sch Med, Brigham & Womens Hosp, Dept Obstet & Gynecol, Boston, MA 02115 USA
[3] Eastern Virginia Med Sch, Dept Obstet & Gynecol, Norfolk, VA 23501 USA
[4] Yale Univ, Sch Med, Dept Obstet Gynecol & Reprod Sci, New Haven, CT USA
[5] Rush Univ, Dept Obstet & Gynecol, Chicago, IL 60612 USA
[6] Fetal Diagnost Ctr, Pasadena, CA USA
[7] William Beaumont Hosp, Dept Obstet & Gynecol, Royal Oak, MI 48072 USA
[8] Thomas Jefferson Univ, Ctr Med, Dept Radiol, Philadelphia, PA 19107 USA
[9] Krankenhaus Nordw, Dept Obstet & Gynecol, Frankfurt, Germany
[10] Univ Calif San Diego, Dept Radiol, San Diego, CA 92103 USA
[11] Massachusetts Gen Hosp, Dept Radiol, Boston, MA 02114 USA
[12] Univ S Florida, Dept Obstet & Gynecol, Tampa, FL 33620 USA
[13] Ctr Fetal Med & Womens Ultrasound, Los Angeles, CA USA
[14] NYU, Dept Obstet & Gynecol, New York, NY 10016 USA