MR Diffusion Kurtosis Imaging (DKI) of the Normal Human Uterus in Vivo During the Menstrual Cycle

Background The uterus undergoes dynamic changes throughout the menstrual cycle. Diffusion kurtosis imaging (DKI) is based on the non‐Gaussian distribution of water molecules and can perhaps represent the changes of uterine microstructure. Purpose To investigate the temporal changes in DKI‐parameters of the normal uterine corpus and cervix during the menstrual cycle. Study Type Prospective. Population 21 healthy female volunteers (26.64 ± 4.72 years) with regular menstrual cycles (28 ± 7 days). Field Strength/Sequence Readout segmentation of long variable echo‐trains (RESOLVE)‐based DKI and fast spin‐echo T2‐weighted sequences at 3.0T. Assessment Each volunteer was scanned during the menstrual phase, ovulatory phase, and luteal phase. Regions of interest (ROI) were manually delineated in the endometrium, junctional zone, and myometrium of the uterine body, and in the mucosal layer, fibrous stroma layer, and loose stroma layer of the cervix. The mean K app (diffusion kurtosis coefficient), D app (diffusion coefficient), and ADC (apparent diffusion coefficient) values were measured in the ROI. Statistical Tests ANOVA with Bonferroni or Tamhane correction. Intraclass correlation coefficient (ICC) for assessing agreement. P < 0.05 was considered statistically significant. Results During the menstrual cycle, the highest K app (0.848 ± 0.184) and lowest D app (1.263 ± 0.283 *10 −3 mm 2 /sec) values were found in the endometrium during the menstrual phase. The D app values for the myometrium were significantly higher than those of the endometrium and the junctional zone in every phase. Meanwhile, the D app values for the three zonal structures of the cervix during ovulation were significantly higher than those during the luteal phase. However, there was no significant difference in the ADC values of the loose stroma between ovulation and the luteal phase ( P = 0.568). The reproducibility of DKI parameters was good (ICC, 0.857–0.944). Data Conclusion DKI can show dynamic changes of the normal uterus during the menstrual cycle. Level of Evidence 2 Technical Efficacy Stage 2