1. Department of Radiology; St. Olavs University Hospital; Trondheim; Norway
2. Department of Radiology; Stavanger University Hospital; Stavanger; Norway
3. Department of Anesthesiology; St. Olavs University Hospital; Trondheim; Norway
4. Department of Gynecology and Obstetrics; St. Olavs University Hospital; Trondheim; Norway