Stellant d

All patients underwent multi-phase contrast-enhanced CT imaging using a pancreas protocol. After the acquisition of non-contrast images, an intravenous contrast material (iohexol (350 mg of iodine per milliliter), Omnipaque; GE Healthcare, United States) was injected via the antecubital vein using a power injector (Stellant D; Medrad, Indianola, PA) at a dose of 1.5 mL/kg and a rate of 3–4 mL/s. CT scans of the PPP and PVP were initiated after the bolus of contrast media 20 and 60 s after an upper abdominal aortic enhancement of 200 Hounsfield units (HU), respectively. Non-contrast and PPP images were acquired from the level of the diaphragm to the level of the umbilicus, and PVP images were obtained from the level of the diaphragm to level of the symphysis pubis. Images were acquired with 64 or 256 multi-detector CT scanners (Brilliance 64, iCT256; Philips Medical Systems, Cleveland, OH, USA). The scanning parameters were as follows: 64 × 0.625 or 128 × 0.6205 mm collimation; a rotation speed of 0.5 s; a pitch of 0.641 or 0.993; and a kvP of 120. The effective mAs ranged from 70 to 390 mAs using an automatic tube current modulation technique (Dose-Right; Philips Medical Systems, Best, the Netherlands). Axial and coronal CT images were reconstructed using filtered back projection with 4 mm-thick sections at 3 mm increments.

Using a third‐generation DSCT scanner (SOMATOM Force, Siemens Medical Solutions, Forchheim, Germany), electrocardiography (ECG)‐gated cardiac CT scanning was performed. A retrospective ECG‐gated spiral scan with ECG‐based tube current modulation was applied to multiphase of 0%–90% of the R‐R interval. Automatic exposure control was active, enabling both the adjustment of tube voltage and tube current based on the topogram information. A bolus of 60–70 ml of contrast material (iomeprol; Iomeron 400, Bracco Imaging S.p.A, Milan, Italy) was administered by a power injector (Stellant D, Medrad, Indianola, PA, USA) at 4.5 ml/s followed by 40 ml of saline. An automated bolus tracking system was used to synchronize the arrival of the contrast material with the initiation of the scan. CCTA scan was performed with a tube voltage of 120 kVp, a rotation time of 250 ms, and adaptive tube current (185–380 mA). The effective radiation dose of each scan was calculated by multiplying the dose‐length product by 0.014 mSv/mGy × 1 cm as the constant k‐value. Automatically selected the best cardiac diastolic period, images were reconstructed at a section thickness of 0.75 mm and an increment of 0.6 mm with a Bv40 kernel. The selected FOV was 180mm and the matrix was 512 × 512.

The interval between preoperative CT examination and surgery ranged from 0 to 13 days (6.8 ± 3.1 days) for the occult PC group and from 1 to 14 days (7.0 ± 3.6 days) for the control group. Contrast-enhanced CT examination was performed following injection of intravenous nonionic contrast material (2 mL/kg; iopromide, Ultravist 370: Bayer, Berlin, Germany) with power injection (Stellant D, Medrad, Indianola, PA) at a rate of 3 mL/sec. 16-, 64-, or 256-channel MDCT (Mx 8000, Brilliance 64, or iCT256; Philips Medical Systems, Cleveland, OH) were used for 61, 34, and 7 patients, respectively. The patients ingested 1.2 L of water just before the CT scan. CT scanning of portal venous phase was done after the bolus contrast media injection with a delay of 60 seconds after the aortic enhancement of 150 HU. CT scans were acquired under the following parameters: 120 kV; collimation, any of 16 x 1.5 or 64 x 0.625 or 128 x 0.625 mm; rotation time, 0.5 seconds; pitch, 1.25, 0.641, or 0.993. Tube current was automatically modulated (Dose-Right; Philips Medical Systems), and axial and coronal images were reconstructed with 4-mm thickness at 3-mm intervals by using filtered back projection.