Extracellular volume fraction determined by equilibrium contrast-enhanced dual-energy CT as a diagnostic indicator in patients with renal masses.

PURPOSE: This study aimed to evaluate the feasibility of equilibrium contrast-enhanced dual-energy computed tomography (DECT) compared with tumor single-energy CT (SECT) to calculate the extracellular volume (ECV) fraction for differentiation between benign and malignant renal masses.

METHODS

The sample included 77 patients with renal masses who underwent DECT between March 2019 and July 2021. Unenhanced and 120-kVp equivalent images were used to calculate tumor SECT-derived ECV fractions. Iodine density images were obtained from equilibrium-phase DECT for calculating DECT-derived ECV fractions. Relationships between SECT- and DECT-derived ECV fractions were examined by Pearson correlation analysis. Consistency between the SECT- and DECT-derived ECV fractions was evaluated using the intraclass correlation coefficient and Bland-Altman analyses. The discrimination performance of ECV for malignant and benign renal masses was compared using the independent sample t-test and receiver operating characteristic curve analysis.

RESULTS

The SECT- and DECT-derived ECV fractions were strongly correlated ( r = 0.756, P < 0.001). The Bland-Altman plot of the SECT- and DECT-derived ECV fractions revealed a small bias (-1.6%). The ECV fraction was significantly higher for malignant renal masses than for benign masses (SECT, P < 0.001; DECT, P < 0.001). The area under the curve of DECT-ECV and SECT-ECV was 0.948 and 0.921, respectively. The sensitivity of DECT-ECV and SECT-ECV was 93.65% and 90.48%, respectively, while the specificity was 85.71% and 85.71%, respectively.

CONCLUSIONS

Our findings show good correlation between DECT-ECV and SECT-ECV. The ECV fraction determined by equilibrium contrast-enhanced DECT is a potential new imaging marker for differentiating malignant from benign renal masses.