Explainable machine learning model integrating clinical and radiomic features for predicting acute suppurative cholecystitis

Table 1 The demographic data and radiologic feature of 311 patients, n (%)

Variable	Training set (n = 150)	Validation set (n = 61)	Test set (n = 100)	P value
Age (years), median IQR	67.00 (56.50, 78.00)	69.00 (57.50, 78.50)	68.00 (55.25, 78.00)	0.883
Sex (male)	76 (50.7)	30 (49.2)	48 (48.0)	0.917
WBC (× 109/L), median IQR	10.36 (7.50, 14.72)	9.85 (6.55, 14.84)	9.95 (6.66, 13.34)	0.544
NE (%), median IQR	84.75 (72.35, 90.83)	83.40 (70.00, 88.35)	82.40 (71.42, 90.92)	0.309
ALT (U/L), median IQR	29.40 (16.30, 53.58)	25.00 (16.50, 42.60)	25.40 (15.65, 50.75)	0.406
STB (μmol/L), median IQR	20.35 (13.20, 32.58)	17.20 (11.40, 27.00)	21.15 (14.45, 35.00)	0.120
UCB (μmol/L), median IQR	13.05 (9.20, 20.05)	11.00 (6.70, 16.80)	13.45 (7.60, 20.38)	0.065
GB wall thickness (mm), median IQR	3.20 (2.60, 4.20)	3.00 (2.30, 3.85)	3.20 (2.33, 4.00)	0.390
GB stones	93 (62.0)	36 (59.0)	65 (65.0)	0.7991
Cystic duct or neck of the stones	65 (43.3)	23 (37.7)	40 (40.0)	0.723
Stratification of bile in the lumen	17 (11.3)	5 (8.2)	3 (3.0)	0.0461
Gas within the GB lumen	4 (2.7)	0 (0.0)	6 (6.0)	0.093
Necrosis of the GB wall	31 (20.7)	14 (23.0)	19 (19.0)	0.834
Pericholecystic exudation or fluid	66 (44.0)	25 (41.0)	32 (32.0)	0.159
Pus	60 (40)	19 (31.14)	35 (35)	0.441

¹Fisher’s exact test.

IQR: Interquartile range; NE: Neutrophil granulocytes; WBC: White blood cells; ALT: Alanine aminotransferase; STB: Serum total bilirubin; GB: Gallbladder; UCB: Unconjugated bilirubin.

Table 2 Univariate and multivariate analysis of clinical features, n (%)

Variable	ASC (n = 60)	Non-ASC (n = 90)	Univariate P value	Multivariate analysis
				P value	OR (95%CI)
Age (years), median IQR	70.5 (59.00, 81.50)	65.50 (50.00, 75.25)	0.041
Sex (male)	34 (56.7)	42 (46.7)	0.23
BMI, median IQR	24.17 (21.38, 27.13)	24.00 (21.59, 27.08)	0.844
WBC (× 109/L), median IQR	11.77 (8.31, 15.65)	9.44 (6.77, 14.19)	0.016
NE (%), median IQR	90.35 (81.33, 93.50)	80.60 (66.70, 88.75)	< 0.001	< 0.001	2.456 (1.520-3.969)
ALT (U/L), median IQR	28.00 (16.00, 60.03)	30.25 (19.48, 50.60)	0.524
STB (μmol/L), median IQR	23.00 (14.30, 37.83)	18.65 (12.70, 27.80)	0.107
UCB (μmol/L), median IQR	13.60 (9.33, 22.88)	12.60 (9.00, 19.83)	0.322
GB wall thickness (mm), median IQR	3.65 (2.70, 4.50)	3.10 (2.43, 3.85)	0.017
GB stones	41 (68.3)	55 (61.1)	0.367
Cystic duct or neck of the stones	29 (48.3)	36 (40)	0.313
Stratification of bile in the lumen	4 (6.7)	13 (14.4)	0.141
Gas within the GB lumen	4 (6.7)	0 (0.0)	0.0241
Necrosis of the GB wall, median IQR	22 (36.7)	9 (10)	< 0.001	< 0.001	5.255 (2.091-13.206)
Pericholecystic exudation or fluid	38 (63.3)	28 (31.1)	< 0.001
Time between CT and intervention (days)	0 (0-1)	0 (0-1)	0.672

¹Fisher’s exact test.

The interventions include percutaneous cholecystostomy and laparoscopic cholecystectomy. OR: Odds ratio; CI: Confidence interval; IQR: Interquartile range; BMI: Body mass index; NE: Neutrophil granulocytes; WBC: White blood cells; ALT: Alanine aminotransferase; STB: Serum total bilirubin; GB: Gallbladder; UCB: Unconjugated bilirubin; CT: Computed tomography; ASC: Acute suppurative cholecystitis.

Table 3 Diagnostic performance of the clinical model, radiomics model and fusion model for predicting acute suppurative cholecystitis

Model	Dataset	AUC (95%CI)	Sensitivity (%)	Specificity (%)	Accuracy (%)	DeLong test P value
						P vs clinical	P vs radiomics
Clinical	Training	0.7841 (0.7079-0.8557)	53.3	86.7	73.3
Radiomics	Training	0.8043 (0.7224-0.8724)	63.3	85.5	76.7	0.686
Fusion	Training	0.8478 (0.7773-0.9070)	65.0	85.6	77.3	0.046	0.039
Clinical	Validation	0.7450 (0.5915-0.8800)	57.9	92.9	82.0
Radiomics	Validation	0.7807 (0.6405-0.9021)	63.2	83.3	77.1	0.713
Fusion	Validation	0.8396 (0.7214-0.9385)	63.2	90.5	82.0	0.140	0.192
Clinical	Test	0.7459 (0.6345-0.8497)	45.7	87.7	73.0
Radiomics	Test	0.7631 (0.6658-0.8515)	62.9	73.9	70.0	0.794
Fusion	Test	0.8264 (0.7327-0.9063)	71.4	83.1	79.0	0.049	0.047

AUC: Area under the receiver operating characteristic curve; CI: Confidence interval.