Whole-volume histogram analysis of spectral-computed tomography iodine maps characterizes HER2 expression in gastric cancer

Table 1 Clinical characteristics between two sub-groups of patients with gastric adenocarcinoma

Clinical characteristics	HER-2 positive (n = 21)	HER-2 negative (n = 80)	P value
Age (years)	59.33 ± 8.534	64.15 ± 10.152	0.049
Sex			0.221
Male	19	63
Female	2	17
Specimen type			0.007
Gastrectomy	14	72
Biopsy	7	8
Tumor location			0.676
Cardia	10	30
Body	4	16
Antrum	7	34
Differentiation degree			0.001
Poorly differentiated	6	55
Non-poorly differentiated	11	18
Lauren classification			0.023
Intestinal type	8	22
Diffuse type	0	25
Mixed type	5	18

Table 2 Comparison of spectral-computed tomography histogram parameters and HER-2 status in gastric cancer

Parameters	HER-2 positive (n = 21)	HER-2 negative (n = 80)	P value
Min	-2.000 (-5.518, 1.000)	-0.500 (-7.750, 5.000)	0.143
Max	37.000 (29.500, 40.622)	41.000 (36.000, 50.750)	0.018
Mean	17.429 (14.923, 19.341)	21.176 (17.529, 25.899)	0.001
Std	4.383 (3.663, 4.949)	5.037 (4.285, 5.883)	0.015
Variance	19.198 (13.417, 24.489)	25.366 (18.359, 34.604)	0.015
CV	0.269 ± 0.067	0.245 ± 0.071	0.163
Skewness	-0.051 (-0.246, 0.020)	-0.064 (-0.289, 0.182)	0.569
Kurtosis	0.282 (0.020, 0.683)	0.280 (0.037, 0.617)	0.861
Entropy	2.843 ± 0.256	3.012 ± 0.259	0.009
1st percentile	6.037 (3.500, 9.000)	9.000 (6.000, 12.75)	0.007
5th percentile	10.000 (7.000, 12.000)	12.500 (10.000, 16.750)	0.003
10th percentile	11.000 (9.000, 13.500)	14.000 (12.000, 18.750)	0.003
25th percentile	14.086 (12.000, 16.500)	17.000 (14.000, 21.750)	0.002
50th percentile	18.000 (15.000, 19.500)	21.000 (18.000, 25.750)	0.001
75th percentile	20.122 (18.000, 23.000)	24.000 (21.000, 30.500)	0.001
90th percentile	24.000 (19.500, 26.000)	27.000 (24.000, 35.000)	0.001
95th percentile	24.147 (21.000, 28.000)	29.000 (25.000, 37.750)	0.001
99th percentile	28.171 (24.000, 30.500)	32.500 (28.000, 40.750)	0.001
Lesion volume	14.643 (4.214, 41.820)	9.930 (4.418, 21.191)	0.266

CV: Coefficient of variation.

Table 3 Receiver operating characteristic curve results of the iodine map histogram parameters to identify HER-2 status

Parameters	AUC (95%CI)	Sensitivity (%)	Specificity (%)	Accuracy (%)	Cutoff value	P value	Youden index
Max	0.669	76.2	53.7	58.4	40.62	0.018	0.299
Mean	0.734	81.0	61.2	65.3	19.54	0.001	0.422
SD	0.674	85.7	50.0	57.4	5.05	0.015	0.357
Variance	0.674	85.7	50.0	57.4	25.50	0.015	0.357
Entropy	0.698	85.7	50.7	57.4	3.02	0.005	0.357
1st percentile	0.691	85.7	47.5	55.4	9.18	0.007	0.332
5th percentile	0.708	71.4	60.0	62.4	11.50	0.003	0.314
10th percentile	0.713	76.2	57.5	61.4	13.50	0.003	0.337
25th percentile	0.715	76.2	58.7	62.4	15.50	0.003	0.349
50th percentile	0.736	76.2	61.2	64.4	19.50	0.001	0.374
75th percentile	0.731	81.0	55.0	60.4	27.50	0.001	0.360
90th percentile	0.733	66.7	71.2	70.3	24.57	0.001	0.379
95th percentile	0.737	71.4	67.5	68.3	26.50	0.001	0.389
99th percentile	0.740	76.2	65.0	67.3	30.50	0.001	0.412

AUC: Area under the curve.

Table 4 Correlations between spectral-computed tomography histogram parameters and HER-2 status of gastric cancers

Parameters	Correlation coefficient	P value
Max	-0.237	0.017
Mean	-0.329	0.001
SD	-0.244	0.014
Variance	-0.244	0.014
Entropy	-0.278	0.005
1st percentile	-0.270	0.006
5th percentile	-0.293	0.003
10th percentile	-0.300	0.002
25th percentile	-0.303	0.002
50th percentile	-0.332	0.001
75th percentile	-0.325	0.001
90th percentile	-0.328	0.001
95th percentile	-0.333	0.001
99th percentile	-0.337	0.001