Diffusion-weighted MRI at 3T in Endometrial Cancer: Correlation of Apparent Diffusion Coefficient with Histopathological Prognostic Parameters

Abstract

To evaluate the value of apparent diffusion coefficient (ADC) for the differentiation of histological subtypes in endometrial cancer, and to assess if ADC values correlate with histopathological parameters.Descriptive study.Department of Radiology, Faculty of Medicine, Ondokuz Mayis University between January 2016 and December 2019.Eighty-three patients (mean age: 60.28 ± 9.07) with endometrial cancer underwent diffusion-weighted imaging (DWI) at 3T before surgery. The mean ADC (ADCmean) and minimum ADC (ADCmin) values of the tumours were assessed to predict histological subtype of endometrial cancer, grade of tumour, presence of myometrial invasion, lower uterine segment involvement, cervical involvement, lymphovascular invasion, and lymph node metastasis.Sixty patients (72.3%) were diagnosed with endometrioid carcinoma, and 23 patients (27.7%) were diagnosed with non-endometrioid carcinoma. The median ADCmean/ADCmin of endometrioid and non-endometrioid tumours were 0.72/0.58 ×10-3 mm2/s and 0.82/0.63 ×10-3 mm2/s, respectively. ADCmean and ADCmin were significantly different between endometrioid and non-endometrioid tumours (p=0.016 and p=0.048). For the endometrioid carcinomas, ADCmean and ADCmin were significantly different between low-grade (G1 and G2) and high-grade (G3) tumours (ADCmean/ADCmin = 0.75/0.65 vs. 0.59/0.49 x10-3 mm2/s, p=0.010 and p=0.013). Myometrial invasion, lymphovascular invasion, cervical involvement, lower uterine involvement, serosal involvement and lymph node metastasis were not significantly associated with ADC values.ADC measurements were useful for differentiating endometrioid and non-endometrioid carcinomas. High-grade endometrioid carcinomas had significantly lower ADC values compared to low-grade ones. Key Words: Endometrial cancer, Diffusion-weighted MRI, Apparent diffusion coefficient, Prognostic factors, Histological grade.