Quantitative diffusion-weighted magnetic resonance imaging of normal and diseased uterine zones

Magnetic resonance (MR) imaging has been established as the best imaging modality for the detection, localization, and staging of uterine cancers. Recently, the usefulness of diffusion-weighted imaging (DWI) in the diagnosis of cancers has been reported in several studies.

To calculate the apparent diffusion coefficient (ADC) values of normal uterine zones as well as benign and malignant uterine diseases, and to determine a cut-off ADC value for the quantitative detection of uterine malignancies with DWI.

Eighty-seven patients (mean age 53 years) with 107 benign and malignant uterine pathologies and 50 healthy controls (mean age 38 years) were enrolled in the study. DWI was performed with b factors of 0, 500, and 1000 s/mm(2).

The ADC values of benign and malignant lesions were compared using Student's t test. The mean and the standard deviation of the ADC values of the control group were as follows: myometrium 1.76+/-0.19 x 10(-3) mm(2)/s, junctional zone 0.99+/-0.18 x 10(-3) mm(2)/s, endometrium 1.65+/-0.33 x 10(-3) mm(2)/s, and cervix 1.71+/-0.17 x 10(-3) mm(2)/s. There was a statistically significant difference among the ADC values of normal myometrium and leiomyomas (1.47+/-0.36 x 10(-3) mm(2)/s; P<0.009), endometrium and endometrial carcinomas (0.86+/-0.13 x 10(-3) mm(2)/s; P<0.001), myometrium-junctional zone and adenomyosis (1.24+/-0.20 x 10(-3) mm(2)/s; P<0.001), and cervix and cervical carcinomas (0.91+/-0.14 x 10(-3) mm(2)/s; P<0.001). The ADC values differed significantly between malignant (0.88+/-0.11) and benign lesions (1.55+/-0.33; P<0.01). A cut-off value for malignant lesions of 1.05 x 10(-3) mm(2)/s yielded a sensitivity, specificity, and accuracy of 95.83%, 94.55%, and 94.94%, respectively.

The present study shows that ADC measurements have the potential to quantitatively differentiate between normal and cancerous tissues of the uterine zones. We propose adding DWI as an adjunct sequence in the MR protocol for the assessment of uterine lesions.