[Diffusion-weighted imaging characteristics of uterine leiomyomas with different pathological subtypes at 3.0 T].

OBJECTIVE: To investigate the imaging features of uterine leiomyomas with different pathological subtypes on DWI. METHODS: Clinical records and MR images of pathologically confirmed uterine leiomyomas were retrospectively collected from the Second Affiliated Hospital of Wenzhou Medical University from June 2012 to April 2015. A total of 60 uterine leiomyomas were found and evaluated.All the patients were divided into three groups according to different pathological types, which included 17 cases of cellular leiomyomas, 10 cases of degenerated leiomyomas and 33 cases of ordinary leiomyomas.The DWI signal and ADC values in cellular portion of the lesions and adjacent normal myometrium (the control group) were measured. RESULTS: (1) Most cellular leiomyomas showed hyperintensity on DWI (15/17), while degenerated leiomyomas manifested hypointensity, isointensity or hyperintensity signal on DWI, and most ordinary leiomyomas displayed isointensity signal on DWI (57.6%, 19/33). (2) The ADC values of cellular leiomyomas, degenerated leiomyomas and ordinary leiomyomas were (1.01±0.14)×10(-3) mm(2)/s, (1.73±0.49)×10(-3) mm(2)/s and (1.38±0.22)×10(-3) mm(2)/s respectively.The ADC values of adjacent normal myometrium (the control group) were (1.35±0.16)×10(-3) mm(2)/s.There were no significant statistical differences in the ADC values between ordinary leiomyomas and adjacent normal myometrium (P=0.623). There were significant statistical differences in the ADC values among other groups(all P<0.05). (3)The ROC curve showed that the diagnostic threshold for cellular leiomyomas was 1.11×10(-3) mm(2)/s, the sensitivity and specificity were 88.2%and 93.0% respectively. CONCLUSION: The signal intensity on DWI and the ADC values are different in uterine leiomyomas with different pathological subtypes.Combination of these two parameters in clinical practice may be helpful to reflect the histopathological characteristics of uterine leiomyomas.