Could temporal window for the computed tomography hepatic venography (CTHV) be extended?: A comparative study between...

To investigate the feasibility of extending the acceptable temporal window for hepatic venography with dual-energy spectral CT imaging.

Five normal pigs anesthetized intramuscularly were scanned on a multislice CT (GE Discovery HD750 CT) after bolus contrast injection. Twelve CT scans with dual-energy spectral imaging mode were performed on each pig with a 10-second interval. Both conventional polychromatic and monochromatic image sets were reconstructed. The optimal energy level for hepatic vein imaging was selected from the monochromatic image sets based on the contrast-to-noise ratio (CNR) analysis. Subjective assessment of image quality was performed on volume-rendering images at 12 imaging points in time.

The CNRs for hepatic veins in the polychromatic, default monochromatic 65 keV, and the optimal energy images were 2.24 ± 1.09, 3.48 ± 1.73, and 6.72 ± 2.56, respectively, with a significant difference among 3 groups (P < 0.001). There was no acceptable temporal window for imaging hepatic veins in the polychromatic group, but a peak plateau existed. The temporal window in the 65-keV group was 20 seconds, whereas it was 70 seconds in the optimal energy group.

Compared with conventional polychromatic CT images, monochromatic images provided superior CNR for hepatic veins and 3.5 times temporal window of hepatic venography in spectral CT.