. 2020 Aug 21;35(3):179–188. doi: 10.7555/JBR.34.20200039

Table 2. Comparisons of CT imaging features between different tumor grades according to WHO 2017 classification in PNENs.

CT features	Group	Grade (WHO 2017)			P	P ^*	P ^**
CT features	Group	PNENs G1 (n)	PNENs G2 (n)	PNENs G3 (n)	P	P ^*	P ^**
CT: computed tomography; WHO: World Health Organization; PNENs: pancreatic neuroendocrine neoplasms; HU: Hounsfield units. P^: PNENs G1/G2 vs.* PNENs G3; P^*: PNENs G1 vs.* PNENs G2.P-values were calculated using chi-square test.
Tumor size (mm)	Mean±SD	21.93±14.40	45.93±32.56	47.80±19.17	<0.001	0.005	<0.001
	<20	25	10	0	<0.001	0.003	<0.001
	≥20	14	32	13
Location	Head/neck	21	24	8	0.881	0.686	0.765
Location	Body/tail	18	18	5
Shape	Regular	31	22	0	<0.001	<0.001	0.010
Shape	Irregular	8	20	13
Margin	Well-defined	37	35	1	<0.001	<0.001	0.099
Margin	Ill-defined	2	7	12
Heterogeneity	Absent	24	17	2	0.010	0.018	0.058
Heterogeneity	Present	15	25	11
Edge enhancement	Absent	32	31	12	0.314	0.226	0.373
Edge enhancement	Present	7	11	1
Cystic or necrotic components	Absent	34	27	11	0.040	0.462	0.017
Cystic or necrotic components	Present	5	15	2
Intratumoral blood vessels	Absent	38	32	8	0.003	0.027	0.005
Intratumoral blood vessels	Present	1	10	5
Vascular invasion	Absent	38	31	6	<0.001	0.001	0.003
Vascular invasion	Present	1	11	7
Calcification	Absent	37	37	12	0.547	0.909	0.278
Calcification	Present	2	5	1
Enhancement pattern (arterial phase)	Hyper-	33	33	2	<0.001	<0.001	0.484
Enhancement pattern (arterial phase)	Iso-/hypo-	6	9	11
Enhancement pattern (portal phase)	Hyper-	29	26	2	<0.001	<0.001	0.230
Enhancement pattern (portal phase)	Iso-/hypo-	10	16	11
Enhancement degree (HU), mean±SD	Arterial phase	110.78±33.72	118.95±33.77	81.75±40.54	0.005	0.001	0.369
Enhancement degree (HU), mean±SD	Portal phase	99.95±22.18	101.14±21.63	76.04±26.86	0.002	0.001	0.899
Tumor-to-pancreas enhancement ratio, mean±SD	Arterial phase	1.36±0.40	1.32±0.53	0.97±0.38	0.028	0.002	0.202
Tumor-to-pancreas enhancement ratio, mean±SD	Portal phase	1.26±0.25	1.22±0.29	0.96±0.34	0.005	<0.001	0.275
Peak attenuation phase	Arterial phase	24	32	8	0.317	0.585	0.154
Peak attenuation phase	Portal phase	15	10	5
Upstream pancreatic duct dilatation	Absent	32	28	9	0.274	0.714	0.114
Upstream pancreatic duct dilatation	Present	7	14	4
Common bile duct dilatation	Absent	39	39	8	0.003	<0.001	0.089
Common bile duct dilatation	Present	0	3	5
Lymph node metastases	Absent	38	36	5	<0.001	<0.001	0.061
Lymph node metastases	Present	1	6	8
Liver metastases	Absent	39	39	9	0.001	0.001	0.089
Liver metastases	Present	0	3	4