Predictive value of portal venous phase computed tomography parameters for anastomotic stricture after D2 gastrectomy

Table 1 Comparison of clinical data between two groups, mean ± SD/n (%)

Variable	Stricture group (n = 23)	Non-stricture group (n = 176)	t/χ2/Z value	P value
Age (years)	63.2 ± 8.9	61.1 ± 9.8	1.024	0.307
Sex			0.313	0.576
Male	16 (69.6)	112 (63.6)
Female	7 (30.4)	64 (36.4)
Body mass index (kg/m2)	25.8 ± 3.2	23.4 ± 3.1	3.521	0.001
Diabetes mellitus	9 (39.1)	32 (18.2)	5.324	0.021
Hypertension	8 (34.8)	51 (29.0)	0.337	0.562
Preoperative serum albumin (g/L)	35.2 ± 4.8	38.6 ± 5.1	-3.092	0.002
Tumor location			8.762	0.013
Cardia/fundus	11 (47.8)	42 (23.9)
Body	6 (26.1)	52 (29.5)
Antrum/pylorus	6 (26.1)	82 (46.6)
Tumor-node-metastasis stage			2.156	0.541
Stage I	3 (13.0)	38 (21.6)
Stage II	8 (34.8)	62 (35.2)
Stage III	12 (52.2)	76 (43.2)
Surgical approach			6.891	0.009
Total gastrectomy	14 (60.9)	58 (33.0)
Distal gastrectomy	9 (39.1)	118 (67.0)
Digestive tract reconstruction			7.234	0.027
Billroth I	3 (13.0)	56 (31.8)
Billroth II	5 (21.7)	48 (27.3)
Roux-en-Y anastomosis	15 (65.2)	72 (40.9)
Stapler model			5.127	0.024
Diameter 25 mm	16 (69.6)	82 (46.6)
Diameter 29 mm	7 (30.4)	94 (53.4)
Anastomotic technique			1.738	0.187
End-to-end anastomosis	4 (17.4)	54 (30.7)
End-to-side anastomosis	19 (82.6)	122 (69.3)
Postoperative complications (≥ grade II)1	8 (34.8)	26 (14.8)	5.671	0.017
Anastomotic leakage	2 (8.7)	7 (4.0)		0.2682
Intra-abdominal infection	3 (13.0)	6 (3.4)		0.0542
Hemorrhage	1 (4.3)	4 (2.3)		0.4702
Pulmonary infection	2 (8.7)	8 (4.5)		0.3292
Wound infection	2 (8.7)	5 (2.8)		0.1812
Postoperative adjuvant therapy	15 (65.2)	98 (55.7)	0.758	0.384

¹The same patient may experience multiple complications simultaneously, so the sum of individual categories may exceed the total complication count.

²Fisher’s exact test was used.

Table 2 Comparison of portal venous phase computed tomography quantitative parameters between two groups, mean ± SD/median (interquartile rage)

Parameter	Stricture group (n = 23)	Non-stricture group (n = 176)	t/Z value	P value
PV-HU (HU)	128.6 ± 18.3	142.5 ± 21.6	-3.012	0.003
Liver-HU (HU)	89.4 ± 12.7	92.8 ± 14.2	-1.124	0.263
Aorta-HU (HU)	94.2 ± 15.8	92.6 ± 16.4	0.452	0.652
SV-HU (HU)	118.3 ± 16.9	132.7 ± 19.5	-3.452	0.001
Portal perfusion index	0.70 ± 0.09	0.66 ± 0.11	1.706	0.09
PV-HU/aorta-HU	1.38 ± 0.18	1.56 ± 0.22	-3.847	< 0.001
nPV-HU (%)	35.2 (28.6-42.8)	52.4 (41.6-64.3)	-4.126	< 0.001

PV-HU: Portal vein computed tomography value; Liver-HU: Hepatic parenchyma computed tomography value; Aorta-HU: Abdominal aorta computed tomography value; SV-HU: Splenic vein computed tomography value; nPV-HU: Normalized portal vein computed tomography value.

Table 3 Multivariate logistic regression analysis of anastomotic stricture

Variable	β	SE	Wald χ2	Odds ratio	95%CI	P value
Body mass index ≥ 25 kg/m2	1.186	0.512	5.367	3.274	1.201-8.928	0.021
Diabetes mellitus	1.082	0.498	4.721	2.951	1.112-7.832	0.03
Total gastrectomy	1.324	0.487	7.392	3.758	1.447-9.762	0.007
Stapler diameter 25 mm	1.156	0.476	5.901	3.177	1.250-8.074	0.015
nPV-HU (per 10% increase)	-0.892	0.318	7.869	0.41	0.220-0.765	0.005
PV-HU/aorta-HU (per 0.1 increase)	-0.756	0.287	6.938	0.469	0.268-0.824	0.008

Odds ratio < 1 for normalized portal vein computed tomography (CT) value and portal vein CT value/abdominal aorta CT value indicates that increased values are protective factors, meaning decreased values increase anastomotic stricture risk. aorta-HU: Abdominal aorta computed tomography value; nPV-HU: Normalized portal vein computed tomography value; PV-HU: Portal vein computed tomography value.

Table 4 Receiver operating characteristic curve analysis of computed tomography quantitative parameters for predicting anastomotic stricture

Parameter	Area under the curve	95%CI	Optimal cutoff	Sensitivity (%)	Specificity (%)	Positive predictive value (%)	Negative predictive value (%)
nPV-HU	0.812	0.726-0.898	42.50%	78.3	72.7	27.3	96.2
PV-HU/aorta-HU	0.768	0.672-0.864	1.45	73.9	71	25	95.4
PV-HU	0.697	0.586-0.808	133.5 HU	69.6	64.8	20.5	94.2
SV-HU	0.724	0.618-0.830	124.0 HU	73.9	63.6	21	94.9

aorta-HU: Abdominal aorta computed tomography value; nPV-HU: Normalized portal vein computed tomography value; PV-HU: Portal vein computed tomography value; SV-HU: Splenic vein computed tomography value.

Table 5 DeLong test comparison of area under the curve among different computed tomography quantitative parameters

Comparison	ΔAUC	Z value	P value
nPV-HU vs PV-HU/aorta-HU	0.044	0.892	0.372
nPV-HU vs PV-HU	0.115	2.156	0.031
nPV-HU vs SV-HU	0.088	1.987	0.047
PV-HU/aorta-HU vs PV-HU	0.071	1.324	0.186
PV-HU/aorta-HU vs SV-HU	0.044	0.876	0.381
PV-HU vs SV-HU	-0.027	0.512	0.609

aorta-HU: Abdominal aorta computed tomography value; nPV-HU: Normalized portal vein computed tomography value; PV-HU: Portal vein computed tomography value; SV-HU: Splenic vein computed tomography value; ΔAUC: Difference in area under the curve.

Table 6 Comparison of diagnostic performance between combined prediction model and single computed tomography parameters

Predictive indicator	Area under the curve	95%CI	Sensitivity (%)	Specificity (%)	Positive predictive value (%)	Negative predictive value (%)
Combined prediction model	0.893	0.832-0.954	87	80.1	36.4	97.9
nPV-HU	0.812	0.726-0.898	78.3	72.7	27.3	96.2
PV-HU/aorta-HU	0.768	0.672-0.864	73.9	71	25	95.4
Clinical factors model1	0.798	0.708-0.888	73.9	75.6	28.3	95.7

¹Clinical factors model includes four clinical factors: Body mass index ≥ 25 kg/m², diabetes mellitus, total gastrectomy, and 25 mm stapler diameter.

aorta-HU: Abdominal aorta computed tomography value; nPV-HU: Normalized portal vein computed tomography value; PV-HU: Portal vein computed tomography value.

Table 7 Comparison of computed tomography quantitative parameters in subgroups by surgical approach, mean ± SD/median (interquartile rage)

Surgical approach	Stricture group	Non-stricture group	Statistic	P value
Total gastrectomy (n = 72)	n = 14	n = 58
nPV-HU (%)	33.8 (26.4-40.2)	50.6 (40.2-62.8)	Z = -3.512	< 0.001
PV-HU/aorta-HU	1.35 ± 0.17	1.54 ± 0.21	t = -3.124	0.002
Distal gastrectomy (n = 127)	n = 9	n = 118
nPV-HU (%)	38.2 (30.4-46.8)	53.6 (42.8-65.2)	Z =-2.687	0.007
PV-HU/aorta-HU	1.42 ± 0.19	1.57 ± 0.23	t = -2.012	0.046

aorta-HU: Abdominal aorta computed tomography value; nPV-HU: Normalized portal vein computed tomography value; PV-HU: Portal vein computed tomography value.