Chest CT protocol
Images were obtained in supine position by one of the two following CT scanners : an Aquilion Prime 160 (Toshiba, Japan) or a Somatom Force CT VB10 (Siemens Healthinners, Germany). Mean scanning parameters were: tube voltage = 120 kV, automatic dose modulation (30-210 mAs), matrix 512 x 512, pitch 0,35-0,99, slice thickness = 0,5 mm, and a field of view = 500 mm x 500 mm. A 0,5 mm slice thickness was used after image reconstruction. When a pulmonary embolism was suspected, iodinated contrast media (300 mg/l) was intravenously injected (3 to 4 ml/s) according to patient weight, with bolus tracking in the main pulmonary artery. Images reconstructed were archived and transferred to the informatic network (PACS).