CT-based radiomics signature of visceral adipose tissue and bowel lesions for identifying patients with Crohn’s disease resistant to infliximab

Insights into Imaging

Table 4 Predictive performance comparison of bowel and VAT-bowel radiomics models in differentiating PNR from PR in the training and validation cohorts

Variable	DeLong’s test		McNemar’s test		Hosmer-Lemeshow test		IDI
Variable	AUC (95% CI)	P^a	Accuracy (95% CI)	P^b	χ²	P^c	Index (95% CI)	P^d
Training cohort (PNR/PR = 33/79)
Bowel radiomics model	0.832 (0.750–0.896)	0.165	0.732 (0.643–0.805)	0.076	11.056	0.199	0.031 (0.006–0.056)	0.016
VAT-bowel radiomics model	0.873 (0.797–0.928)	0.165	0.821 (0.740–0.881)	0.076	5.668	0.684	0.031 (0.006–0.056)	0.016
Internal validation cohort (PNR/PR = 14/34)
Bowel radiomics model	0.784 (0.641–0.889)	0.098	0.708 (0.568–0.818)	0.070	5.850	0.664	0.042 (0.005–0.078)	0.024
VAT-bowel radiomics model	0.840 (0.706–0.930)	0.098	0.813 (0.681–0.898)	0.070	10.08	0.259	0.042 (0.005–0.078)	0.024
External validation cohort (PNR/PR = 22/49)
Bowel radiomics model	0.799 (0.687–0.885)	0.376	0.690 (0.575–0.786)	0.035	9.139	0.331	0.037 (0.003–0.070)	0.032
VAT-bowel radiomics model	0.833 (0.726–0.911)	0.376	0.817 (0.711–0.890)	0.035	7.262	0.509	0.037 (0.003–0.070)	0.032

PNR primary nonresponse to infliximab therapy, PR response to infliximab therapy. Bowel radiomics model, radiomics model based on the features extracted from the whole inflamed bowel; VAT-bowel radiomics model, radiomics model based on the features extracted from both visceral adipose tissue and the whole inflamed bowel. AUC, area under ROC curve; CI, confidence interval; IDI, integrated discriminant improvement. ^ap value is the significance level of the comparison of AUC between the bowel and VAT-bowel radiomics models according to DeLong’s test. ^bp value is the significance level of the comparison of accuracy between bowel and VAT-bowel radiomics models according to McNemar’s test. ^cp value is the significance level of the difference between the prediction probability and the true value for each model according to Hosmer-Lemeshow test. ^dp value is the significance level of the improvement (IDI > 0) in predictive performance of the new model (VAT-bowel model) over the old model (bowel model)