Dual-energy CT extracellular volume fraction for predicting the chemotherapeutic response in pancreatic ductal adenocarcinoma.

OBJECTIVES: This study aimed to investigate the value of the extracellular volume fraction (ECV) derived from dual-energy computed tomography (DECT) in predicting the chemotherapeutic response in patients with pancreatic ductal adenocarcinoma (PDAC). METHODS: This study included 112 patients with pathologically confirmed PDAC who underwent dynamic contrast-enhanced DECT prior to chemotherapy. Iodine concentrations were measured on delayed-phase iodine maps within the tumor and aorta, and the ECV was calculated on the basis of the iodine concentration. Treatment response to chemotherapy was assessed according to the RECIST 1.1 criteria. Univariate and multivariate analyses were conducted to identify predictors of treatment response. Receiver operating characteristic (ROC) curves were used to evaluate the predictive performance of the identified variables. RESULTS: The tumor ECV was significantly lower in the response group (23.64%) than in the nonresponse group (38.13%)(P < 0.001). The tumor ECV was also an independent predictor of poor response to chemotherapy (OR = 1.259; P = 0.023) and had the highest diagnostic value, with an area under the curve (AUC) value of 0.83, significantly outperforming the venous phase iodine concentration (IC_VP; AUC = 0.73). When the optimal cutoff value of the ECV was used (31.8%), the sensitivity, specificity and accuracy for predicting the response group were 81.0%, 70.4% and 75.9%, respectively. The Delong test revealed a significant difference in the AUC value between the ECV model and the IC_VP model (P = 0.026). CONCLUSIONS: DECT-derived ECV represents a promising noninvasive biomarker for predicting chemotherapy response in PDAC patients, with lower ECV values potentially indicating a more favorable therapeutic outcome.