[1] Univ Texas Southwestern, Dallas, TX 75390 USA
[2] Siemens AG, Healthcare Sect MRI, Erlangen, Germany
[3] Siemens Healthcare, Malvern, PA USA
[4] Johns Hopkins Univ Hosp, Russell H Morgan Dept Radiol & Radiol Sci, Baltimore, MD 21287 USA
[5] Univ Zurich Hosp, Dept Radiol, CH-8091 Zurich, Switzerland