1. Fetal Medicine Unit, S. Orsola-Malpighi Hospital; University of Bologna; Italy
2. Department of Obstetrics and Gynaecology; Carlo Poma Hospital; Mantova Italy
3. Maternal-Fetal Medicine Department, Hospital Clinic; University of Barcelona; Spain
4. Department of Radiology and Neuroradiology; Children's hospital V. Buzzi; Italy
5. Department of Obstetrics, Maggiore Hospital; University of Parma; Italy