Omnipaque 300

All 37 patients were examined using multidetector-row CT. CT imaging was performed using a 8-slice CT scanner (LightSpeed Ultra; GE Healthcare, Milwaukee, WI, USA), 16-slice CT scanner (LightSpeed 16; GE Healthcare, Milwaukee, WI, USA), or a 64-slice CT scanner (Brilliance CT 64; Philips Medical Systems, Best, The Netherlands). Unenhanced CT images were obtained in all 37 patients, and contrast-enhanced CT images were obtained in 32 patients. Contrast-enhanced CT images were obtained 45 s after initiating intravenous bolus injection of 100 mL of nonionic iodine contrast material (Omnipaque 300 [300 mg of iodine per ml], Daiichi Sankyo, Tokyo, Japan or Optiray 240 [240 mg of iodine per ml], Mallinckrodt Inc., Hazelwood, MO, USA) at an injection rate of 2 mL/s. Axial and coronal multiplanar reconstruction images were reconstructed with 2.5 mm section thickness and no overlap. These CT images were reconstructed using bone and soft-tissue algorithms.

CT images were acquired using a 16-detector row CT unit (Alexion TSX-034A, Canon Medical Systems, Tochigi, Japan.). The technical parameters for CT were as follows: rotation time, 0.75 s; slice thickness, 2 mm; field of view, 160–340 mm; matrix dimensions, 512 × 512; reconstruction interval, 0.5–1 mm; detector pitch, 15; collimator pitch, 0.94; X-ray tube potential, 120 kVp; and X-ray tube current, variable milliamperage determined by x-, y-, and z-axis dose modulation. An intravenous iodine-based contrast medium (Omnipaque 300, Daiichi Sankyo, Tokyo, Japan) was administered using a power injector at a dose of 450 mg/kg into a cephalic catheter. After unenhanced scanning, post-contrast images were acquired 30–60 seconds after the initiation of contrast medium injection. CT images were retrospectively analyzed using a Digital Imaging and Communications in Medicine viewer (OsiriX Imaging Software, version 8.0, OsiriX Pixmeo, Geneva, Switzerland).

Using a power injector (Dual Shot; Nemoto-Kyorindo, Tokyo, Japan), the researchers delivered contrast medium (Omnipaque-300; Daiichi-Sankyo, Tokyo, Japan) via a 22-gauge catheter into the antecubital vein. To determine the scan timing, the researchers acquired a test-bolus scan at the patella level and obtained a time-density curve for the popliteal arteries. The test-bolus scan was comprised of serial low-dose scans (100 kVp and 50 mAs) without table movement. The inter-scan interval was 1.0 second. The contrast medium (15.0 mL) was injected at a rate of 3.0 mL/sec and followed with 20.0 mL of a saline solution delivered at the same injection rate. Acquisition of the dynamic monitoring scans began 18.0 second, after the start of contrast medium injection. To obtain a time attenuation curve, the researchers placed a region of interest (ROI) in the popliteal arteries at the patella level. When there was a difference in the peak time of the popliteal arteries, a performance was executed on the main scan using mean peak time of both popliteal arteries. The scan start time was defined as the arrival time plus 5.0 second, based on the time-enhancement curves of the test-bolus scan.
For LE-CTA, 85.0 mL of the contrast medium were intravenously administered at an injection rate of 3.0 mL/sec. This was followed with 20.0 mL of a saline solution delivered at the same injection rate.