RESUMO
AIM: To evaluate the role of diffusion-weighted imaging (DWI) in the detection of endometrial carcinoma and to correlate the apparent diffusion coefficient (ADC) value with Ki-67 expression. MATERIALS AND METHODS: Fifty-two patients with invasive cancer who underwent pelvic MRI were prospectively evaluated using DWI with b-values of 0 and 1000 s/mm2.The ADC values from standard DWI were measured. The expression of Ki-67 in histological specimens was analysed using immunohistochemistry. The ADC values of endometrial carcinoma and normal endometrial parenchyma were compared. Relationships between ADC values and Ki-67 expression were determined using Wilcoxon's signed rank test and the Kruskal-Wallis test. RESULTS: Endometrial carcinoma was detected at DWI as a hyperintense area in 92.3% (48/52) of patients. There was a significant difference in the mean ADC values between endometrial carcinoma and normal endometrial parenchyma (1.39±0.27×10-3 versus 0.93±0.21×10-3 mm2/s, p<0.001). The mean ADC values of grade 1 patients were significantly higher than those of grade 3 patients (1.01±0.16×10-3 versus 0.83±0.21×10-3 mm2/s, p<0.05). The mean ADC values of stage IB patients were significantly lower than those of stage IA patients (0.86±0.16×10-3 versus 1.04±0.21×10-3 mm2/s, p<0.01). The mean ADC values of high Ki-67 expression patients were significantly lower than those of low Ki-67 expression patients (0.82±0.12×10-3 versus 1.16±0.12×10-3 mm2/s, p<0.001). There was a significant negative correlation between the mean ADC value and Ki-67 expression (r=-0.82, p<0.001). CONCLUSION: The ADC value was a helpful parameter for detecting the tumour grade, stage, and proliferation of endometrial carcinoma, and may further improve patient prognosis and contribute to the development of more effective treatment programmes.