Magnetic resonance imaging thicknesses and apparent diffusion coefficient values of the endometrium and junction zone in women of reproductive age

Background The endometrium and uterine junction zone often change throughout the menstrual cycle. Some pathological conditions may appear normal in uterine imaging, which will lead to missed diagnosis and misdiagnosis. Purpose To evaluate the changes in the thickness and apparent diffusion coefficient (ADC) values of the endometrium and uterine junction zone throughout the menstrual cycle in magnetic resonance imaging (MRI) of women of reproductive age. Material and Methods Data were collected from 40 healthy women of reproductive age with regular menstrual cycles from January 2017 to April 2018. They underwent four total MRI sessions during the menstrual, proliferation, and early and late secretive phases. The main MRI sequences were T2-weighted (T2W) volume isotropic turbo spin echo acquisition (VISTA) spectral attenuated inversion recovery (SPAIR) and diffusion-weighted imaging (b = 0, 600, 800, 1000 s/mm 2 ), which were used to measure the thicknesses and ADC values of endometrium and uterine junction zone. Results First, the endometrium was thinnest during the menstrual phase and thickest in the late secretive phase. Second, the uterine junction zone was thinnest in the late secretive phase and thickest in the menstrual phase. Third, the ADC values of the endometrium were lowest in the menstrual phase and peaked in the early secretive phase. Finally, the ADC values of the uterine junction zone were lowest in the menstrual phase and peaked in the late secretive phase. Conclusion The endometrium and uterine junction zone showed cyclic changes. Radiologists should consider these changes in the thickness and ADC values when analyzing MRI images of the uterus.