Non-invasive staging of endometrial fibrosis using diffusion-weighted imaging: a feasibility study.

RESEARCH QUESTION: Can diffusion-weighted imaging (DWI) be used to stage endometrial fibrosis?

DESIGN

This prospective study included 41 healthy women, 30 patients with mild to moderate endometrial fibrosis (MMEF) and 102 patients with severe endometrial fibrosis (SEF). Endometrial thickness and DWI-related parameters, specifically the mean intensity (ADCROI and ADCVOI) and standard deviation (ADC-SDROI and ADC-SDVOI) of the endometrial apparent diffusion coefficient (ADC) values within a region of interest (ROI) on a mid-sagittal ADC map, and volume of interest (VOI) of the entire endometrium in the corpus uteri, were measured and analysed.

RESULTS

Endometrial thickness, endometrial ADCVOI and ADCROI were significantly higher in healthy women (11.7 mm, 1.31  ×  10-3 mm2/s and 1.36  ×  10-3 mm2/s) than MMEF patients (7.5 mm, P < 0.001; 1.23  ×  10-3 mm2/s, P = 0.001; and 1.26  ×  10-3 mm2/s, P = 0.003) and SEF patients (6.2 mm, 1.15  ×  10-3 mm2/s and 1.23  ×  10-3 mm2/s; all P < 0.001). Endometrial ADC-SDVOI and ADC-SDROI were significantly higher in SEF patients (0.24 and 0.24) than healthy women (0.16 and 0.13) and MMEF patients (0.18 and 0.16) (all P < 0.001). The degree of endometrial fibrosis was negatively correlated with endometrial thickness, endometrial ADCVOI and ADCROI (Spearman's rho = -0.662, -0.526 and -0.349) and positively correlated with endometrial ADC-SDVOI and ADC-SDROI (Spearman's rho 0.729 and 0.713) (all P < 0.001). Compared with endometrial thickness measurements, endometrial magnetic resonance imaging parameters, particularly DWI-related parameters, demonstrated excellent accuracy in distinguishing normal endometrium, MMEF and SEF (areas under the curve >0.800).

CONCLUSIONS

DWI is particularly effective for accurately staging the microstructural changes associated with endometrial fibrosis.