Spectral CT in the demonstration of the gastrocolic ligament: a comparison study

To investigate the performance of spectral CT in the depiction of the gastrocolic ligament (GCL) compared to conventional polychromatic CT.

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.

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).

Spectral CT can improve the visualisation of the GCL compared to polychromatic CT.