Aquilion one 320 row

Computed tomography was performed using an Aquilion One 320-row multi-detector computed tomography scanner (Toshiba Medical Systems, Japan). Imaging was triggered manually during the arterial phase and scan parameters were as follows: detector collimation 320 × 0.5 mm; tube current between 300 and 500 mA depending on BMI; tube voltage 100–120 kV; gantry rotation time 270 or 350 ms; and temporal resolution 135 or 175 ms. A 55 ml bolus of 100% iohexol 56.6 g/75 ml (Omnipaque 350) was injected at a rate of 5 ml per second into the antecubital vein, followed by a 20 ml bolus of a 30:70 mixture of contrast medium and saline, followed by a 30 ml bolus of saline. All patients underwent were prospective electrocardiogram gated scans. After image acquisition, raw data was exported, postprocessed, and analysed on a dedicated workstation (Vitrea Fx 6.6.2, Vital Images, USA).

The patients were examined by the Toshiba Aquilion™ ONE 320-row helical CT machine (Toshiba Corp., Tokyo, Japan). The parameters of group A were set as 120 kV and 300 mA, group B as 100 kV and automatic milliamperes, and group C as 80 kV and automatic milliamperes. Iopamidol injection (Iopamidol) (Patheon Italia S.p.A., Ferentino, Italy; sub-packaging: BRACCO; approval no. NMPN J20150090) was used as the contrast agent. The concentration used was 370 mg iodine/ml, 25 ml of 0.9% sodium chloride was injected with an injection rate of 5 ml/sec. Scanning mode: Helical acquisition. The patient was guided to stay in the supine position with both hands naturally falling on both sides of the body; then the CT scan was performed for the patient's neck and head, from the level of the aortic arch to the level of the top of the head.