Fig. 3

CT texture analysis of small bowel-GISTs with different risk levels. CT images of high risk in arterial phase (a) and venous phase (b) show an irregular external growth mass situated in the right upper abdomen with heterogeneous enhancement in a 66-year-old female. Histograms in arterial phase (c) and venous phase (d) show lower distribution of CT values. Mean attenuation and entropy were 47.00HU and 5.23 in arterial phase, 57.64HU and 5.39 in venous phase, respectively. CT images of intermediate risk in the arterial phase (e) and venous phase (f) show a rounded external mass at the proximal jejunum in a 60-year-old male. Histograms in arterial phase (g) and venous phase (h) show the distribution of CT values. Mean attenuation and entropy were 68.72HU and 5.31 in arterial phase, 70.22HU and 5.66 in venous phase, respectively. CT images of low risk in the arterial phase (i) and venous phase (j) show an irregular internal mass with obvious enhancement located at the descending duodenum in a 60-year-old female. Histograms in arterial phase (k) and venous phase (l) show higher distribution of CT values. Mean attenuation and entropy were 155.15HU and 6.21 in arterial phase, 133.26HU and 6.14 in venous phase, respectively