Improved differentiation between stage I-II endometrial carcinoma and endometrial polyp with combination of APTw and IVIM MR imaging.

Purpose: To assess the value of amide proton transfer weighted (APTw) combined with intra-voxel incoherent motion (IVIM) imaging in differential diagnosis of stage I-II endometrial carcinoma (EC) and endometrial polyp (EP).

Methods: A total of 53 female patients (37 cases with EC and 16 cases with EP) confirmed by surgical resection or biopsy from June 2019 to Jan. 2022 were retrospectively reviewed. All patients underwent 3.0 T magnetic resonance imaging (MRI) examination including diffusion weighted imaging (DWI), APTw and IVIM scans. The pure diffusion coefficient (D), pseudo-diffusion coefficient (D), perfusion fraction (f), apparent diffusion coefficient (ADC) and APT values were independently measured by two observers. Intra-class correlation coefficients (ICC) were used to test the consistency of measurements by the two observers. Mann-Whitney U test was performed to analyze the difference of each parameter between EC and EP groups. Receiver operator characteristic (ROC) analysis was performed, and the Delong test was used for ROC curve comparison. Pearson's correlation analysis was used to assess the correlation between APTw and IVIM parameters.

Results: There was no significant difference in clinical manifestations between the two groups (P > 0.05). APT and D values of the EC group were significantly higher than those of the EP group [APT: 2.64 ± 0.50% vs. 2.05 ± 0.58%; and D: (54.06 ± 36.06) × 10 mm/s vs. (30.54 ± 16.67) × 10 mm/s]. D, f and ADC values of EC group were significantly lower than those of EP group [D: 0.62(0.53,0.76) × 10 mm/s vs. (1.45 ± 0.48) × 10 mm/s; f: 22.18 ± 8.08% vs. 30.80 ± 8.92%; and ADC: (0.88 ± 0.16) × 10 mm/s vs. (1.57 ± 0.43) × 10 mm/s]. The area under ROC curves were observed as: AUC (IVIM+APT) > AUC (D) > AUC (ADC) > AUC (APT) > AUC (f) > AUC (D). Delong test suggested statistical significance between AUC by APT and D, D and D, D and f, D and ADC, APT and com(IVIM+APT), D and com(IVIM+APT), as well as f and com(IVIM+APT). No significant correlation between the APT and IVIM parameters was observed in either EC or EP group.

Conclusion: Both APT and IVIM parameters showed statistical differences between EC and EP. With combination of APT and IVIM parameters, the diagnostic accuracy between EC and EP can be significantly improved.