Purpose: To investigate the performance of spectral CT in the depiction of the gastrocolic ligament (GCL) compared to conventional polychromatic CT.
Methods: Gemstone spectral CT and conventionally polychromatic CT examinations were randomly allocated to be performed on 62 consecutive patients. A total of 11 groups of monochromatic images were generated on energy levels ranging from 40 to 140 keV at an interval of 10 keV. A five-score classification system was used to evaluate the performances of CT images in the demonstration of GCL. The inter-observer agreement between two radiologists in their evaluation of the GCL by each method was evaluated using kappa statistics.
Results: There were statistically significant differences between the spectral CT and polychromatic CT in their abilities to highlight the GCL (observer 1: χ(2) = 18.310, P < 0.001; observer 2: χ(2) = 19.780, P < 0.001). The distinct display (score ≥ 3) rates of the GCL by integrated monochromatic images were higher than that of polychromatic images (P < 0.001). The best energy level for displaying the GCL by spectral CT was 50-70 keV. The kappa value for the image scores on the integrated keV images between the two radiologists was higher than that for polychromatic CT images (P < 0.01).
Conclusions: Spectral CT can improve the visualisation of the GCL compared to polychromatic CT.