A 320-row CT system (Aquilion ONE, Toshiba, Otawara, Japan) was used in all patients for CTPA scanning. All the exams were performed with non-ECG-gated helical scan protocol. Patients were positioned supine and feet first into the gantry. Dual scanograms were used for determination of the anatomical coverage. The volume was placed to cover the entire lung fields from the pulmonary apex to the posterior costophrenic angle. Each volume CTPA data acquisition was acquired with a single breath-hold. The CT gantry rotation time was 330 ms. The tube voltage was 100–120 kV; effective tube current was 200–300 mA adjusted by personal body mass index (BMI). The collimation was 0.625 mm; pitch was 0.99. All the data were reconstructed using a standard soft-tissue and lung kernel (FC56). Images were reconstructed with slice thickness of 0.9 mm, interval of 0.45 mm.
A total of 40–50 mL contrast medium (Omnipaque 350, GE Healthcare, Shanghai, China) was intravenously injected by using a dual-head power injector with the injection rate of 3.5–4.5 mL/s adjusted according to BMI and the CT data acquisition time. A saline chaser bolus of 30 mL was injected with the same rate as the contrast medium. A region of interest was placed at the level of the main pulmonary artery for bolus tracking. The exposure was triggered with a 5 s delay after the 150 HU threshold was reached.
A total of 40–50 mL contrast medium (Omnipaque 350, GE Healthcare, Shanghai, China) was intravenously injected by using a dual-head power injector with the injection rate of 3.5–4.5 mL/s adjusted according to BMI and the CT data acquisition time. A saline chaser bolus of 30 mL was injected with the same rate as the contrast medium. A region of interest was placed at the level of the main pulmonary artery for bolus tracking. The exposure was triggered with a 5 s delay after the 150 HU threshold was reached.
Free full text: Click here
