Iomeprol

Two dual-source CT scanners (SOMATOM Definition Flash or SOMATOM Force; Siemens, Germany) were used to examine all patients. The non-ionic contrast media used were iopamidol (370 mgI/mL; Bayer Healthcare, Germany) or iomeprol (350 mgI/mL; Eisai, Japan). An automated power injector was used to administer 100 mL of non-ionic contrast medium at a flow rate of 22.2 mgI/kg/s and an additional 40-mL bolus of 0.9% saline solution at the same flow rate through a 22-gauge catheter.
The automatic bolus tracking method with a region of interest (ROI) placed on the pulmonary artery trunk, which triggered 250 Hounsfield units (HU), was used, and the CTPA scan of CTPA started 10 s after the trigger.
The following parameters were used in the SOMATOM Definition Flash: tube voltage, 140 and 100 kV; detector collimation, 2 × 64 mm × 0.6 mm; rotation time, 330 ms; and pitch, 0.55. The following parameters were used in the SOMATOM Force: tube voltage, 150 and 90 kV; detector collimation, 2 × 64 mm × 0.6 mm; rotation time, 280 ms; and pitch, 0.55. Lung iodine distribution (iodine map) and LPBV images were generated using a workstation (Syngo Acquisition Workplace; Siemens, Germany). LPBV images were created by the fusion of iodine maps and lung CTPA images.

Penicillin/streptomycin, Dulbecco’s Modified Eagles Medium (DMEM), and DMEM/Ham’s F12 were purchased from Thermo Fisher Scientific Inc. (Kanagawa, Japan). Iomeprol (300 mgI/mL in saline) was purchased from Eisai Co., Ltd., Tokyo, Japan, and G418 was purchased from Merck KGaA, Darmstadt, Germany. Iomeprol contains 300 mg/mL of iodine; 612.4 mg/mL Iomeprol is equivalent to 300 mgI/mL of Iomeprol.

All examinations were performed with the same 64-slice multi-detector CT scanner (Aquilion 64; Toshiba Medical Systems, Otawara, Japan). Images were acquired with a 1 mm slice thickness, a 0.5 sec rotation time, a beam pitch of 0.83, and 120 kVp of x-ray tube voltage. Automatic exposure control was used for dose reduction. CT scans were conducted after intravenous injection of 2 ml/kg of nonionic contrast medium (300 mg of iodine per milliliter: Iomeprol, Eisai, Tokyo, Japan; Iopamidol, Nihon Schering, Osaka, Japan) at a rate of 2.5 ml/sec in 10 patients. Scan areas were from chest to pelvis in eight patients, and from chest to upper abdomen in seven patients. All scans were reconstructed with a field of view of 350 mm in a 512×512 matrix (0.685×0.685 mm in-plane resolution), with a 1.0 mm slice thickness using a soft tissue kernel (FC13 of the Toshiba CT) to maintain a high signal-to-noise ratio (SNR).