Preoperative spectral computed tomography multi-parameter prediction of postoperative complications in colorectal cancer: A single-center retrospective cohort study

Table 1 Comparison of patient baseline characteristics, n (%)

Characteristic	Total (n = 195)	Non-complication group (n = 122)	Complication group (n = 73)	Statistic	P value
General demographic data
Age (years), M (P25, P75)	62 (54, 71)	61 (53, 69)	65 (57, 74)	Z = -2.146	0.032
Gender				χ² = 2.315	0.128
Male	114 (58.5)	67 (54.9)	47 (64.4)
Female	81 (41.5)	55 (45.1)	26 (35.6)
BMI (kg/m²), mean ± SD	23.4 ± 3.2	23.6 ± 3.1	23.0 ± 3.4	t = 1.164	0.245
Smoking history	78 (40.0)	45 (36.9)	33 (45.2)	χ² = 1.308	0.253
Alcohol history	52 (26.7)	29 (23.8)	23 (31.5)	χ² = 1.315	0.251
Past medical history/comorbidities
Hypertension	89 (45.6)	52 (42.6)	37 (50.7)	χ² = 1.191	0.276
Diabetes	31 (15.9)	16 (13.1)	15 (20.5)	χ² = 1.864	0.173
Coronary heart disease	24 (12.3)	12 (9.8)	12 (16.4)	χ² = 1.810	0.178
COPD	18 (9.2)	8 (6.6)	10 (13.7)	χ² = 2.735	0.098
Preoperative examination indicators
Hemoglobin (g/L), mean ± SD	125.3 ± 18.7	128.1 ± 17.2	120.9 ± 20.5	t = 2.517	0.013
White blood cell count (× 109/L), M (P25, P75)	6.8 (5.4, 8.3)	6.5 (5.2, 7.9)	7.2 (5.8, 8.9)	Z = -2.014	0.045
Neutrophil count (× 109/L), M (P25, P75)	4.2 (3.1, 5.6)	3.9 (2.9, 5.2)	4.7 (3.5, 6.1)	Z = -2.364	0.018
Lymphocyte count (× 109/L), M (P25, P75)	1.8 (1.4, 2.3)	1.9 (1.5, 2.4)	1.6 (1.2, 2.1)	Z = -2.289	0.022
Platelet count (× 109/L), mean ± SD	285.4 ± 78.9	278.2 ± 75.1	297.8 ± 84.2	t = -1.622	0.106
Albumin (g/L), mean ± SD	38.9 ± 4.8	40.1 ± 4.2	36.8 ± 5.2	t = 4.624	< 0.001
Prealbumin (mg/L), mean ± SD	268.7 ± 58.3	279.4 ± 52.9	250.1 ± 63.8	t = 3.358	0.001
Total protein (g/L), mean ± SD	68.5 ± 7.2	69.8 ± 6.8	66.4 ± 7.6	t = 3.158	0.002
Creatinine (μmol/L), M (P25, P75)	78.5 (65.2, 93.1)	76.8 (63.4, 91.2)	81.7 (68.9, 96.3)	Z = -1.714	0.087
Blood urea nitrogen (mmol/L), M (P25, P75)	5.8 (4.6, 7.2)	5.6 (4.4, 6.9)	6.2 (5.0, 7.8)	Z = -1.876	0.061
ALT (U/L), M (P25, P75)	25.3 (18.7, 34.2)	24.1 (17.9, 32.5)	27.8 (20.4, 37.1)	Z = -1.502	0.134
AST (U/L), M (P25, P75)	28.9 (22.1, 38.7)	27.2 (21.3, 36.4)	31.8 (24.2, 42.1)	Z = -1.705	0.089
CEA (ng/mL), M (P25, P75)	8.7 (3.2, 18.9)	7.1 (2.8, 15.4)	12.3 (4.7, 24.8)	Z = -2.954	0.003
CA19-9 (U/mL), M (P25, P75)	19.8 (8.4, 45.7)	17.2 (7.6, 38.9)	25.4 (10.8, 58.3)	Z = -2.052	0.041
PT (s), mean ± SD	12.8 ± 1.4	12.6 ± 1.3	13.2 ± 1.5	t = -2.628	0.009
APTT (s), mean ± SD	31.7 ± 4.2	31.2 ± 3.9	32.6 ± 4.7	t = -2.151	0.032
INR, mean ± SD	1.08 ± 0.12	1.06 ± 0.11	1.12 ± 0.13	t = -3.367	0.001
Tumor-related indicators
Tumor location				χ² = 1.725	0.189
Colon cancer	118 (60.5)	77 (63.1)	41 (56.2)
Rectal cancer	77 (39.5)	45 (36.9)	32 (43.8)
TNM stage				χ² = 12.238	0.002
Stage I	38 (19.5)	29 (23.8)	9 (12.3)
Stage II	71 (36.4)	49 (40.2)	22 (30.1)
Stage III	86 (44.1)	44 (36.1)	42 (57.5)
Tumor differentiation				χ² = 6.949	0.031
Well differentiated	42 (21.5)	31 (25.4)	11 (15.1)
Moderately differentiated	123 (63.1)	79 (64.8)	44 (60.3)
Poorly differentiated	30 (15.4)	12 (9.8)	18 (24.7)
Tumor diameter (cm), mean ± SD	4.8 ± 2.1	4.4 ± 1.9	5.5 ± 2.3	t = -3.389	0.001
Surgery-related data
Intraoperative blood loss (mL), M (P25, P75)	180 (120, 280)	160 (110, 240)	220 (150, 350)	Z = -3.872	< 0.001
Number of lymph nodes dissected, mean ± SD	18.7 ± 6.8	19.2 ± 6.5	17.8 ± 7.3	t = 1.410	0.156
Positive margin	23 (11.8)	9 (7.4)	14 (19.2)	χ² = 6.072	0.014
Prophylactic stoma	28 (14.4)	14 (11.5)	14 (19.2)	χ² = 2.146	0.143
ASA grade ≥ III	47 (24.1)	23 (18.9)	24 (32.9)	χ² = 4.831	0.028

BMI: Body mass index; COPD: Chronic obstructive pulmonary disease; ASA: American Society of Anesthesiologists; ALT: Alanine aminotransferase; AST: Aspartate aminotransferase; CEA: Carcinoembryonic antigen; CA19-9: Carbohydrate antigen 19-9; PT: Prothrombin time; APTT: Activated partial thromboplastin time; INR: International normalized ratio.

Table 2 Comparison of preoperative spectral computed tomography parameters between two groups, mean ± SD

Parameter	Non-complication group (n = 122)	Complication group (n = 73)	Statistic	P value
Arterial phase parameters
Tumor iodine concentration (μg/cm³)	18.7 ± 6.8	13.4 ± 5.9	t = 5.487	< 0.001
Normal bowel wall iodine concentration (μg/cm³)	12.3 ± 4.2	11.8 ± 4.5	t = 0.787	0.432
Abdominal aorta iodine concentration (μg/cm³)	210.4 ± 45.7	208.9 ± 48.2	t = 0.214	0.831
Erector spinae iodine concentration (μg/cm³)	11.2 ± 3.8	10.8 ± 4.1	t = 0.731	0.465
Tumor normalized iodine concentration	0.089 ± 0.025	0.064 ± 0.022	t = 7.015	< 0.001
Tumor effective atomic number	8.21 ± 0.47	7.86 ± 0.52	t = 4.729	< 0.001
Tumor λHU	2.84 ± 0.68	2.31 ± 0.59	t = 5.425	< 0.001
Tumor plain CT value (HU)	34.5 ± 8.7	35.1 ± 9.2	t = -0.443	0.658
Tumor CT value (HU)	67.8 ± 18.9	54.2 ± 16.7	t = 5.053	< 0.001
Abdominal aorta CT value (HU)	268.4 ± 52.3	265.7 ± 48.9	t = 0.363	0.717
Erector spinae CT value (HU)	40.8 ± 12.4	40.1 ± 13.7	t = 0.350	0.726
Tumor 40 keV CT value (HU)	142.7 ± 38.4	115.3 ± 32.1	t = 5.030	< 0.001
Tumor enhancement degree (HU)	33.3 ± 15.2	19.1 ± 12.8	t = 6.625	< 0.001
Tumor relative enhancement rate (%)	98.7 ± 47.3	56.2 ± 39.1	t = 6.352	< 0.001
Portal venous phase parameters
Tumor iodine concentration (μg/cm³)	22.9 ± 7.3	16.8 ± 6.4	t = 5.879	< 0.001
Normal bowel wall iodine concentration (μg/cm³)	15.7 ± 5.1	15.2 ± 5.4	t = 0.639	0.524
Abdominal aorta iodine concentration (μg/cm³)	158.3 ± 32.1	155.9 ± 35.4	t = 0.480	0.632
Erector spinae iodine concentration (μg/cm³)	10.4 ± 3.2	9.9 ± 3.6	t = 1.000	0.318
Tumor normalized iodine concentration	0.145 ± 0.031	0.108 ± 0.027	t = 8.406	< 0.001
Tumor effective atomic number	8.45 ± 0.52	8.07 ± 0.58	t = 4.659	< 0.001
Tumor λHU	3.12 ± 0.74	2.58 ± 0.67	t = 5.109	< 0.001
Tumor CT value (HU)	89.4 ± 22.1	71.6 ± 19.8	t = 5.690	< 0.001
Abdominal aorta CT value (HU)	184.7 ± 38.9	181.2 ± 41.3	t = 0.580	0.563
Erector spinae CT value (HU)	40.5 ± 12.1	39.8 ± 13.2	t = 0.369	0.712
Tumor 40 keV CT value (HU)	178.3 ± 45.7	142.9 ± 38.9	t = 5.498	< 0.001
Tumor enhancement degree (HU)	54.9 ± 18.4	36.5 ± 15.7	t = 7.105	< 0.001
Tumor relative enhancement rate (%)	161.8 ± 58.2	106.3 ± 48.9	t = 6.781	< 0.001
Derived parameters
Iodine concentration difference (μg/cm³)	4.2 ± 2.8	3.4 ± 2.1	t = 2.152	0.032
Arterial phase tumor-muscle iodine concentration ratio	1.68 ± 0.42	1.34 ± 0.38	t = 5.642	< 0.001
Portal venous phase tumor-muscle iodine concentration ratio	2.21 ± 0.56	1.79 ± 0.47	t = 5.339	< 0.001
Arterial phase tumor-muscle CT value ratio	1.67 ± 0.38	1.36 ± 0.34	t = 5.718	< 0.001
Portal venous phase tumor-muscle CT value ratio	2.22 ± 0.51	1.83 ± 0.43	t = 5.376	< 0.001

CT: Computed tomography.

Table 3 Univariate logistic regression analysis of clinical variables

Variable	β	SE	χ²	P value	OR	95%CI
Age	0.028	0.013	4.768	0.029	1.028	1.003-1.054
COPD	0.822	0.483	2.897	0.089	2.271	0.880-5.862
Hemoglobin	-0.020	0.008	6.018	0.014	0.980	0.964-0.996
White blood cell count	0.164	0.073	5.005	0.025	1.178	1.021-1.360
Neutrophil count	0.237	0.092	6.652	0.010	1.267	1.058-1.518
Lymphocyte count	-0.491	0.214	5.268	0.022	0.612	0.402-0.932
Albumin	-0.153	0.037	17.011	< 0.001	0.858	0.799-0.922
Prealbumin	-0.009	0.003	9.572	0.002	0.991	0.986-0.997
Total protein	-0.061	0.021	8.421	0.004	0.941	0.903-0.981
Creatinine	0.016	0.008	3.702	0.054	1.016	1.000-1.033
Blood urea nitrogen	0.129	0.063	4.214	0.040	1.138	1.006-1.287
AST	0.018	0.009	3.969	0.046	1.018	1.000-1.036
CEA	0.012	0.004	7.236	0.007	1.012	1.003-1.021
CA19-9	0.006	0.003	5.614	0.018	1.006	1.001-1.011
PT	0.326	0.123	7.019	0.008	1.385	1.086-1.767
APTT	0.075	0.034	4.702	0.030	1.078	1.007-1.154
INR	2.691	0.830	10.517	0.001	14.752	2.896-75.151
TNM stage
Stage II vs Stage I	0.141	0.429	0.108	0.743	1.153	0.493-2.696
Stage III vs Stage I	1.351	0.408	10.990	0.001	3.864	1.742-8.575
Tumor differentiation
Moderate vs well differentiated	0.449	0.391	1.315	0.251	1.565	0.726-3.373
Poor vs well differentiated	1.408	0.448	9.888	0.002	4.091	1.710-9.790
Tumor diameter	0.221	0.067	10.879	0.001	1.248	1.094-1.424
Intraoperative blood loss	0.004	0.001	17.842	< 0.001	1.004	1.002-1.006
Positive margin	1.082	0.434	6.201	0.013	2.950	1.264-6.886
ASA grade ≥ III	0.745	0.316	5.563	0.018	2.108	1.139-3.900

COPD: Chronic obstructive pulmonary disease; ASA: American Society of Anesthesiologists; AST: Aspartate aminotransferase; CEA: Carcinoembryonic antigen; CA19-9: Carbohydrate antigen 19-9; PT: Prothrombin time; APTT: Activated partial thromboplastin time; OR: Odds ratio; CI: Confidence interval; INR: International normalized ratio; TNM: Tumor-nodes-metastasis.

Table 4 Univariate logistic regression analysis of spectral computed tomography parameters

Parameter	β	SE	χ²	P value	OR	95%CI
Arterial phase parameters
Tumor iodine concentration	-0.127	0.027	22.157	< 0.001	0.881	0.837-0.928
Tumor normalized iodine concentration	-35.847	8.251	18.896	< 0.001	< 0.001	< 0.001-0.018
Tumor effective atomic number	-0.854	0.223	14.631	< 0.001	0.426	0.275-0.661
Tumor λHU	-0.658	0.183	12.949	< 0.001	0.518	0.364-0.738
Tumor CT value	-0.039	0.007	28.512	< 0.001	0.962	0.948-0.976
Tumor 40 keV CT value	-0.024	0.004	35.721	< 0.001	0.976	0.968-0.984
Tumor enhancement degree	-0.064	0.011	34.129	< 0.001	0.938	0.917-0.959
Tumor relative enhancement rate	-0.011	0.002	29.374	< 0.001	0.989	0.985-0.993
Portal venous phase parameters
Tumor iodine concentration	-0.135	0.024	32.411	< 0.001	0.874	0.833-0.917
Tumor normalized iodine concentration	-46.124	9.873	21.829	< 0.001	< 0.001	< 0.001-0.012
Tumor effective atomic number	-0.763	0.214	12.683	< 0.001	0.467	0.307-0.710
Tumor λHU	-0.616	0.163	14.344	< 0.001	0.540	0.393-0.742
Tumor CT value	-0.038	0.007	32.014	< 0.001	0.963	0.950-0.976
Tumor 40 keV CT value	-0.021	0.004	30.216	< 0.001	0.979	0.972-0.986
Tumor enhancement degree	-0.060	0.009	42.734	< 0.001	0.942	0.925-0.960
Tumor relative enhancement rate	-0.010	0.002	36.827	< 0.001	0.990	0.987-0.993
Derived parameters
Iodine concentration difference	-0.122	0.057	4.607	0.032	0.885	0.792-0.990
Arterial phase tumor-muscle iodine concentration ratio	-1.294	0.283	20.824	< 0.001	0.274	0.158-0.474
Portal venous phase tumor-muscle iodine concentration ratio	-1.199	0.241	24.671	< 0.001	0.302	0.188-0.485
Arterial phase tumor-muscle CT value ratio	-1.316	0.286	21.133	< 0.001	0.268	0.154-0.466
Portal venous phase tumor-muscle CT value ratio	-1.289	0.246	27.474	< 0.001	0.276	0.171-0.446

OR: Odds ratio; CI: Confidence interval; CT: Computed tomography.

Table 5 Multivariate logistic regression analysis for postoperative complications prediction

Predictive factor	β	SE	χ²	P value	OR	95%CI	VIF
Age	0.041	0.018	5.184	0.023	1.042	1.006-1.080	1.12
Albumin	-0.127	0.047	7.289	0.007	0.881	0.803-0.967	1.34
Portal venous phase tumor normalized iodine concentration	-28.734	8.125	12.511	< 0.001	< 0.001	< 0.001-0.021	1.08
TNM stage (stage III vs stage I)	1.186	0.548	4.685	0.030	3.274	1.119-9.582	1.23
Intraoperative blood loss	0.003	0.001	6.841	0.009	1.003	1.001-1.005	1.15
Constant	1.287	1.952	0.434	0.510	3.621

Model equation: Logit (P) = 1.287 + 0.041 × Age - 0.127 × albumin - 28.734 × portal venous phase tumor normalized iodine concentration + 1.186 × TNM stage (stage III) + 0.003 × intraoperative blood loss. TNM: Tumor-nodes-metastasis; OR: Odds ratio; CI: Confidence interval; VIF: Variance inflation factor.