Ninety milliliters of iodinated contrast agent (370 mgI/mL, Iopromide, Ultravist, Bayer Health care, Germany) at a flow rate of 4 mL/second was administered intravenously. A region of interest (ROI) was placed on the distal abdominal aorta. When the predefined threshold of 150 HU was reached, 6 s later the scan automatically initiated.
The scanning parameters included slice collimation: 80 × 0.5 mm, rotation time: 0.75 s, pitch: 0.637, automatic modulation tube current: 40–200 mA (with noise index SD = 10), and tube voltage: 100 kVp.
The volumetric CT dose index (CTDIvol) and dose-length product (DLP) were automatically saved for each examination. The effective radiation dose was estimated using the DLP multiplied by the conversion factor of 0.0058 at 100 kV reported by Saltybaeva et al. [15 (link)].