Lightspeed pro 16

CTA neck studies were performed on one of our institution's CT scanners, including the Optima 660, Lightspeed Xtra, Lightspeed Pro‐16 or Discovery HD‐750 (GE Healthcare; Milwaukee, WI). CTA studies were acquired in helical scanning mode with coverage extending from the aortic arch to the C1 ring. Studies were collimated at 0.625 mm, with kVp of 120, auto‐mA, and with a rotation time of 0.5 s. For each study, ≈90 mL of nonionic iodinated contrast (iohexol, Omnipaque, GE Healthcare) was administered at a rate of 4 to 5 mL/s using a power injector and SmartPrep region‐of‐interest on the aortic arch via an 18‐gauge peripheral intravenous catheter.

All patients underwent computed tomography angiography (CTA) examinations. Matrix size of DICOM images was 512X512. Morphological parameters were measured from CTA images after volume rendering reconstruction. Scanning was performed on a 320-detector row CT scanner (Aquilion ONE, Toshiba Medical Systems, Tochigi, Japan), a 64-channel multidetector CT scanner (LightSpeed VCT 64, GE Medical Systems, Milwaukee, WI, USA), or a 16-channel multidetector CT scanner (LightSpeed pro 16, GE Medical Systems). Non-ionic contrast agent, Iopromid with 300 mg/ml iodine, was injected via an antecubital vein with a high pressure injector at 3.0 ml/s (1.0–2.0 ml/kg) for the 16-channel multidetector CT; non-ionic contrast agent, Iodixanol 320 or Iohexol 350, was injected via an antecubial vein with a high pressure injector at 4.0 ml/s (0.8–1.0 ml/kg) for the 64-channel multidetector CT or 320-detector rows CT.
Twelve aneurysm morphologic parameters were evaluated, including aneurysm projection, A1 segment configuration, aneurysm size, vessel size, aneurysm height, perpendicular height, neck size, aspect ratio, size ratio, aneurysm angles, vessel angle, and flow angle. These parameters have been defined elsewhere (13 (link)–15 (link)). For completeness and the reader's convenience, we provide detailed aneurysm sizes and angle measurements in Supplementary Figure 1.

CT data were acquired using a General Electric, Lightspeed PRO 16, with a 16-channel multi-detector array. The examination covered four adjacent 5-mm sections immediately above the posterior commissure, parallel to a line between the posterior commissure and the root of the nose. Special care was taken to ensure that a similar slice angulation between CT and MR imaging was achieved. The acquisition parameters were 80 kV, 200 mA, 99 repetitions, four images per cine scan, scan repetition time: 0.5 s, acquisition time: 49.5 s, FOV: 250 × 250 mm², and matrix: 512 × 512. Five seconds after the CT scanning was started, a bolus (4 ml/s) of 50 ml Iopromide (300 mg iodine/ mL, viscosity 4.7 mPa·s @ 37 °C, Ultravist, Schering, Berlin, Germany), followed by a saline flush, was injected into the right ante-cubital vein. Injection duration was 12.5 s.

All CT examinations were performed on a 16- or 64-slice scanner (Light Speed Pro 16, VCT, or Discovery HD 750, GE Healthcare, US). Before the examination, all patients signed the informed consent, were requested to fast from solid food for at least six hours and received 600–1000 mL water orally to achieve gastric distension. All patients were in the supine position during the scan, and the scan covered the upper or the entire abdomen. The patients were trained to hold their breath during the CT scanning. Following the non-contrast scan, 1.5 mL/kg iodinated contrast agent (Omnipaque 350 mg I/mL, GE Healthcare, Shanghai, China) was injected intravenously, at a flow rate of 3.0 mL/s, by using a high-pressure syringe (Medrad Stellant CT injector system; One Medrad Drive Indianola, PA, US). Imaging was obtained with post-injection delays of 30 seconds and 70 seconds, corresponding to the arterial and venous phases, respectively, after initiation of the contrast material injection. The CT scanning parameters were: tube voltage: 120 kVp, tube current: 250–350 mA, slice thickness: 5 mm, slice interval: 5 mm, field of view: 35–50 cm, matrix: 512 × 512, rotation time: 0.7 s, and pitch: 1.375.
The mean interval between CT examination and surgery was 5 days (range: 1–10 days).

CAC was quantified by multi-slice computed tomography (LightSpeed Pro 16; GE Healthcare, Milwaukee, WI). The tomographic axial slices were acquired with a 2.5 mm thickness, prospective acquisition and synchronization to EKG, with a 0.4 seconds rotation, temporal reconstruction by 6 frames per second, and W-ray tube voltage of 120 kV and 350 mA. CAC was quantified as previously described by Agatston et al. [21] (link). Any CAC>0 was categorized as CAC presence. CAC severity was stratified in: 0;>0–100 and >100 Agatston Units (AU).