Cyclic Characteristics of Perfusion and Diffusion in Normal Uterus: A Mono-Exponential and Bi-Exponential DWI...

To evaluate the feasibility of intravoxel incoherent motion (IVIM) MRI for noninvasive assessment of uterine perfusion and diffusion characteristics across different phases of the menstrual cycle.

This prospective study included 27 volunteers with regular menstrual cycles (28±7 d) from December 2020 to May 2023. A zoomed field-of-view single-shot spin-echo echo-planar imaging (SE-EPI) sequence was used to obtain multi-b DWI images. Mono-exponential DWI derived apparent diffusion coefficient (ADC) and IVIM-derived parameters including diffusion D, pseudo diffusion D* and perfusion fraction f in the uterine corpus and cervix were analyzed during the menstrual cycle. Statistics analysis was performed by 1-way analysis of variance (ANOVA).

A total of 21 healthy female participants (mean age: 26.64±4.72 y) were recruited for analysis. Both D and ADC values in each layer of the uterine corpus were lowest during the menstrual phase. However, there was no statistically significant difference in ADC of myometrium between the menstrual and ovulatory phases ( P =0.177). The D values of the 3 layers of the uterine corpus gradually increase from the menstrual phase to the luteal phase, whereas the 3-zone structure of the cervix has the highest D value in the ovulatory phase. During the luteal phase, the D* and f values of the endometrium and cervical mucus layer were lower than those of the other 2 layers ( P <0.05).

IVIM MRI enables noninvasive quantification of uterine perfusion and diffusion dynamics and reveals characteristic variations in the uterine corpus and cervix throughout the menstrual cycle.