Image analysis
tumor, calcification, necrotic, necrosis
NECROSIS, TUMOR, ENLARGED LYMPH NODES, NECROTIC, ULCERATION
Two radiologists (Reviewer 1 with 6 years and Reviewer 2 with 13 years of experience in abdominal imaging) independently reviewed CT images and reached final conclusions by consensus without knowledge of the surgical and pathological information of every patient. The determined CT imaging features included (a) the CT attenuation values (Hounsfield units, HU) in unenhancement phase (CTU), (b) in arterial phase (CTA) and (c) in venous phase (CTV) of the tumor, (d) degree of enhancement in arterial phase (DEAP) and (e) in portal venous phase (DEPP), (f) enhanced potentiality in arterial phase (EPa) and (g) in portal venous phase (EPv), (h) long diameter (LD), (i) short diameter (SD), (j) the ratio of long diameter to short diameter (LD/SD), (k) contour (round; oval; irregular), (l) necrosis (yes or no), (m) calcification (yes or no), (n) surface ulceration (yes or no), (o) intratumoral angiogenesis (yes or no) and (p) peripheral enlarged lymph node (LN) (yes or no). The CT attenuation value was measured by drawing the region of interest (ROI) on the same axial slice of the tumor avoiding vessels, calcification, and the necrotic regions. DEAP or DEPP was obtained by subtracting CTU from CTA or CTV respectively. EPa or EPv was equal to DEAP or DEPP divided by CTU. Enlarged lymph node was considered present if the shortest axis diameter of lymph node was more than 10 mm. Some of the CT features referred to our previous report [