Image acquisition
CAVITY, BEST
Contrast-enhanced chest scans were performed in both arterial phase (AP) and venous phase (VP) on dual-layer spectral detector CT (IQon Spectral CT, Philips Healthcare, Best, The Netherlands). The range of scan was from the thoracic inlet to the bottom of the thoracic cavity in order to cover all lung tissues. After a native chest scan, contrast agent (Iodixanol, 350 mg/mL, GE Healthcare, Ireland) was injected via the cubital vein with a power injector (Ulrich REF XD 2051), at a volume of 80 ml and flow rate of 2.5 mL/s. AP and VP scans were acquired at 25 and 60 s after the contrast agent injection. Spectral CT scan parameters were as follows: tube voltage = 120 kV; automatic tube current exposure control [Dose Right Index (DRI)] = 22; tube rotation time = 0.5 s; detector collimation = 64 × 0.625 mm; a reconstructed slice thickness = 0.9 mm; slice increment = 0.45 mm; field of view = 250 × 250 mm; image reconstruction matrix = 512 × 512. All original images were reconstructed as Spectral Base Image (SBI) datasets with reconstructed slice thickness of 1 mm and increment of 1 mm, then were transmitted to a dedicated post-processing workstation of spectral CT (IntelliSpace Portal 6.5, Philips Healthcare, Best, The Netherlands) for image analysis.