Feasibility of iodine concentration parameter and extracellular volume fraction derived from dual-energy CT for distinguishing type I and type II epithelial ovarian carcinoma.

Objectives: To investigate the feasibility of using the iodine concentration (IC) parameter and extracellular volume (ECV) fraction derived from dual-energy CT for distinguishing between type I and type II epithelial ovarian carcinoma (EOC).

Methods: This study retrospectively included 172 patients with EOC preoperatively underwent dual-energy CT scans. Patients were grouped as type I and type II EOC according to postoperatively pathologic results. Normalized IC (NIC, %) values from arterial-phase (AP), venous-phase (VP) and delay-phase (DP) were measured by two observers. ECV fraction (%) was calculated by DP-NIC and hematocrit. Intra-observer correlation coefficient (ICC) was used to assess the agreement between measurements made by two observers. The differences of imaging parameters between the two groups were compared. Logistic regression was used to select independent predictive factors and establish combined parameter. Receiver operating characteristic curve was used to analyze performance of all parameters.

Results: The ICCs for all parameters exceeded 0.75. All parameters in type II EOC were all significantly higher than those in type I EOC (all P < 0.05). VP-NIC exhibited the highest Area under the curve (AUC) of 0.804, along with 80.39% sensitivity and 71.43% specificity. VP-NIC was identified as the independent factor. The sensitivity and specificity of ECV fraction were 78.43% and 71.43%, respectively. The combined parameter consisting of AP-NIC, VP-NIC, DP-NIC, and ECV fraction yielded an AUC of 0.823, with sensitivity of 76.47% and specificity of 77.14%. The sensitivity of the combined parameter was significantly higher than that of AP-NIC (P = 0.049).

Conclusion: It is valuable for dual-energy CT IC-based parameters and ECV fraction in preoperatively identifying type I and type II EOC.

Critical relevance statement: Dual-energy CT-normalized iodine concentration and extracellular volume fraction achieved satisfactory discriminative efficacy, distinguishing between type I and type II epithelial ovarian carcinoma.