Imaging protocol
CM
We used a bodyweight-adapted CM volume of iohexol 350 mgI/mL (Omnipaque 350, GE Healthcare). The control group received the standard iodine load of 1.4 mL/kg, while the experimental group received 0.7 mL/kg as the CM was diluted 1:1 with saline. This allowed identical injection rate and -time in both groups.The CM was administered using a power injector (CT Exprès TM 4D, Bracco Injeneering SA), with a 50 mL saline flush. We used an automatic bolus tracker with a region of interest (ROI) in the abdominal aorta (AA), 120 Hounsfield units (HU) trigger point, and scan after 15 s. The maximum injected volume was limited to 130 mL, and the minimum to 60 mL.Scans were performed supine, feet-first on a Philips IQon SDCT scanner (Philips Healthcare). The scan parameters were: tube voltage: 120 kVp, collimation: 64*0.625 mm, rotation time: 0.5 s, pitch: 1.171, matrix: 512*512, slice thickness: 0.9 mm, increment: 0.45 mm. Automatic tube current (DoseRight 3D-DOM, Philips Healthcare) was enabled, and the Dose Right Index was set at 21.Conventional images were reconstructed with hybrid iterative reconstruction, iDose 4, level 3, and VMI in 40 and 50 keV with a spectral reconstruction algorithm: spectral B, denoising level 3 on an IntelliSpace Portal 9.0 workstation (Philips Healthcare). In the control group, measurements from the conventional images were analyzed. In the experimental group, measurements from the VMIs at 40 and 50 keV were analyzed. All images were assessed in the axial plane with a 1 mm slice thickness.