Evaluation of amide proton transfer-weighted imaging for endometrial carcinoma histological features: a comparative study with diffusion kurtosis imaging.

OBJECTIVES

To investigate whether amide proton transfer-weighted imaging (APTWI) and diffusion kurtosis imaging (DKI) can be used to evaluate endometrial carcinoma (EC) in terms of clinical type, histological grade, subtype, and Ki-67 index.

METHODS

Eighty-eight patients with EC underwent pelvic DKI and APTWI. The non-Gaussian diffusion coefficient (D), apparent kurtosis coefficient (K), and magnetization transfer ratio asymmetry (MTRasym (3.5 ppm)) were calculated and compared based on the clinical type (type I, II), histological grade (high- and low-grade), and subtype (endometrioid adenocarcinoma (EA) and non-EA). Correlation coefficients were calculated for each parameter with histological grades and the Ki-67 index.

RESULTS

The MTRasym (3.5 ppm) and K values were higher in the type II group and high-grade group than in the type I and low-grade groups, respectively, while the D values were lower in the type I and low-grade groups, respectively (all p < 0.05). The K value was higher in the EA group than in the non-EA group (p = 0.022). The K value was the only independent predictor for the histological grade of EA and the clinical type of EC. The AUC (DKI) was higher than the AUC (APTWI) in the identification of type I and II EC and high- and low-grade EA (Z = 2.042, 2.013, p = 0.041, 0.044), while in the identification of EA and non-EA, only the difference in K was statistically significant. Moreover, the K and MTRasym (3.5 ppm) values and D values correlated positively and negatively, respectively, with histological grade (r = 0.759, 0.555, 0.624, and 0.462, all p < 0.05) and Ki-67 index (r = -0.704, -0.507, all p < 0.05).

CONCLUSION

Both DKI- and APTWI-related parameters have potential as imaging markers in estimating the histological features of EC, while DKI shows better performance than APTWI in this study.

KEY POINTS

• DKI and APTWI can be used to preliminarily evaluate the histological characteristics of endometrial carcinoma (EC). • The K was the only independent predictor for the histological grade of EA and the clinical type of EC. • The K, MTRasym (3.5 ppm), and D correlated positively and negatively, respectively, with histological grade and Ki-67 index.