Significance of apparent diffusion coefficient in the diagnosis of endometrial carcinoma and its pathohistological features.

Abstract

Objectives: MR differentiation between endometrial cancer, hyperplasia, and the normal endometrium using ADC values and their correlation with the pathohistological characteristics of endometrial cancer.

Material and methods: The retrospective study included 131 patients, 55 with endometrial cancer, 21 with hyperplasia, and 55 patients with normal endometrium. Mean ADC values were obtained by measuring the region of interest (ROI) in the corresponding part of the endometrium.

Results: The mean ADC values of endometrial cancer (0.646 ± 0.112 × 10⁻³ mm²/s) were significantly lower than those of endometrial hyperplasia (1.660 ± 0.394 × 10⁻³ mm²/s) and normal endometrium (1.503 ± 0.312 × 10⁻³ mm²/s) (p<0.001), while the ADC values of endometrial hyperplasia did not differ from normal endometrium. No difference was found between ADC values in different grades of endometrial cancer (p=0.219; p>0.05), depending on the depth of myometrial invasion (p=0.506; p>0.05), the presence of metastases in lymph nodes (p=0.202; p>0.05), and lymphovascular invasion (p=0.366; p>0.05). Regarding the FIGO stage, the only significant difference in ADC values was obtained for stage 4b (p=0.023; p<0.05). ADC values below 1.120 × 10⁻³ mm²/s with 100% sensitivity and 94.5% specificity indicate the presence of cancer, with a positive predictive value of 94.8% and a negative predictive value of 100%.

Conclusions: The ADC is a useful diagnostic tool in the differentiation between endometrial cancer and hyperplasia with high sensitivity and specificity, but its use in differentiating pathohistological characteristics of endometrial cancer is not possible.