Lightspeed 64

All patients underwent abdominal CT at our institution. Vendors of CT equipment included GE Healthcare (Lightspeed 16, Lightspeed 64, Discovery 750, and Brightspeed Elite, Waukesha, WI, USA), Philips Healthcare (Brilliance 16 and ICT256, Amsterdam, the Netherlands), and Toshiba Medical Systems (Aquilion One, Otawara, Japan). The CT tube voltage was 120 or 140 kVp, and the automatically controlled tube current was 110–720 mAs. The CT scan covered from the diaphragm to the pubic symphysis. If possible, fast for 4-6 hours before the scan, followed by ingestion of 1000–1500 ml of 2.5% mannitol water solution orally 40–60 min prior to the scan. Some patients underwent an unenhanced CT, followed by contrast-enhanced imaging; others were scanned with IV contrast only. Contrast-enhanced CT was performed after a rapid bolus of iopromide (Ultravist 370, 370 mg/mL, Bayer Schering Pharma, Berlin, Germany) (1.5 mL/kg) at a rate of 3–5 mL/s, followed by a 20-mL saline flush using a power injector. Images were routinely obtained in the arterial, intestinal, or portal venous phases at 30, 45, or 70 s, respectively.

The pieces of CT equipment used in this study were Philips iCT 256, GE Light Speed 64, and Philips Brilliance 64. The CT parameters were as follows: voltage was 120 kV, tube current was 120–250 mA, matrix was 512 × 512, layer thickness was 5 mm, reconstruction thickness was 1.25 or 1 mm, lung window width/level was 1,500/550, and mediastinum window width/level was 350/40. Plain and contrast-enhanced CT scans (Ultravist 370 with a dose of 1.5 ml/kg; bolus injection through the antecubital vein using a high-pressure syringe at a rate of 3–3.5 ml/s; three-phase scanning time windows of 30, 60, and 90 s after the injection of the contrast agent) were performed.

The patient underwent a GE Lightspeed 64/Philips Brilliance 256 spiral CT scan at the time of initial diagnosis with the following parameters—tube voltage 80–100 kV, tube current 150–200 mA s, acquisition slice thickness 5.0 mm, pitch 1.1 mm, collimation 0.6 mm, and reconstruction slice thickness 1.25 mm. CT scanning was performed with iodixanol, iodine concentration of 320 mg/l, dose of 1.5–2.0 ml/kg and flow rate of 0.5–3.5 ml/s. Arterial and venous phase scans were performed 20–28 s and 55–66 s after contrast injection, respectively.