Diffusion tensor imaging (DTI) of the normal human uterus in vivo at 3 tesla: comparison of DTI parameters in the different uterine layers

Purpose: To investigate the differences in the fiber architecture and related diffusion tensor imaging (DTI) parameters among different uterine layers of the normal human uterus in vivo at 3 Tesla (T).

Materials and methods: DTI of the uterus was performed for nine healthy women of reproductive age on a 3T scanner. A volume of interest (VOI) was drawn for the outer myometrium (OM), junctional zone (JZ), and endometrium (EM). Apparent diffusion coefficient (ADC), fractional anisotropy (FA), and maximum fiber length were compared using paired Student's t-tests. Fibers were classified into four groups and were visually evaluated.

Results: ADC (×10(-3) mm(2) /s) was highest for OM (1.12), followed by EM (0.97) and JZ (0.83) (OM versus JZ, P < 0.0001; JZ versus EM, P = 0.0001; OM versus EM, P = 0.0057). FA was highest for JZ (0.297), followed by OM (0.257) and EM (0.186) (OM versus JZ, P = 0.0002; JZ versus EM, P < 0.0001; OM versus EM, P < 0.0001). Fibers were longest in OM (42.0 mm), followed by JZ (34.2 mm) and EM (20.0 mm). Circularly oriented fibers were observed in 69% in OM and in 70% in JZ.

Conclusion: DTI of the uterus in vivo revealed layer-wise differences in the microstructure of the uterus.