16 slice spiral ct scanner

A 16-slice spiral CT scanner (Siemens Somatom Sensation Company, Erlangen, Germany) was used with a conventional-slice thickness of 5 mm. All of the lesions were reconstructed at a slice thickness of 1.5 mm and amplified. The patients were instructed to lie in a supine position, raise their arms, breathe in and hold their breath. Volume scanning was subsequently conducted. The scanning range began from the superior aperture of the thorax and ended at the posterior costophrenic angle of the left and right lungs. Abdominal scanning was conducted on certain patients and enhancement scanning was conducted on all patients. Nonionic contrast medium iohexol (Beijing BeiLu Pharmaceutical, Co., Ltd., Beijing, China; 300 mgI/ml, 80–100 ml) was used, and the injection rate ranged between 2.5 and 3.0 ml/sec. Scanning was conducted 30 and 90 sec after the contrast medium had been injected.

Preoperative non-contrast (NC) and contrast-enhanced CT scans were performed for each patient at the two institutions. Institution I performed CT scans using two CT scanners: a 64-slice spiral CT scanner (Siemens, Germany) or a 256-slice spiral CT scanner (Philips, Netherlands). Institution II performed CT scans using four CT scanners: a 16-slice spiral CT scanner (Siemens, Germany), a 64-slice spiral CT scanner (GE, USA), a 64-slice spiral CT scanner (Toshiba, Japan), or a 256-slice spiral CT scanner (Philips, Netherlands).
The parameters for the CT scan were as follows: tube voltage, 100 or 120 kV; tube current, 180–400 mA·s; reconstruction section thickness, 1.25–5.00 mm; pitch, 0.97–1.5; and matrix, 512×512. The scan range was from the skull base to the subclavian region. After routine plain CT scans, contrast-enhanced CT scans were performed after a delay of 20–30 s (arterial phase [AP]) following an intravenous administration of 80–100 mL of iodinated nonionic contrast agent at a rate of 3.0–3.5 mL/s using a high-pressure syringe. The nonionic contrast agent used was iohexol (Yangtze River, China; GE Healthcare, Ireland).