Oscillating Gradient Diffusion‐Weighted MRI for Risk Stratification of Uterine Endometrial Cancer

Background Oscillating gradient diffusion‐weighted imaging (DWI) enables elucidation of microstructural characteristics in cancers; however, there are limited data to evaluate its utility in patients with endometrial cancer. Purpose To investigate the utility of oscillating gradient DWI for risk stratification in patients with uterine endometrial cancer compared with conventional pulsed gradient DWI. Study Type Retrospective. Subjects Sixty‐three women (mean age: 58 [range: 32–85] years) with endometrial cancer. Field Strength/Sequence 3 T MRI including DWI using oscillating gradient spin‐echo (OGSE) and pulsed gradient spin‐echo (PGSE) research sequences. Assessment Mean value of the apparent diffusion coefficient (ADC) values for OGSE (ADC OGSE ) and PGSE (ADC PGSE ) as well as the ADC ratio (ADC OGSE /ADC PGSE ) within endometrial cancer were measured using regions of interest. Prognostic factors (histological grade, deep myometrial invasion, lymphovascular invasion, International Federation of Gynecology and Obstetrics [FIGO] stage, and prognostic risk classification) were tabulated. Statistical Tests Interobserver agreement was analyzed by calculating the intraclass correlation coefficient. The associations of ADC OGSE , ADC PGSE , and ADC OGSE /ADC PGSE with prognostic factors were examined using the Kendall rank correlation coefficient, Mann–Whitney U test, and receiver operating characteristic (ROC) curve. A P value of <0.05 was statistically significant. Results Compared with ADC OGSE and ADC PGSE , ADC OGSE /ADC PGSE was significantly and strongly correlated with histological grade (observer 1, τ = 0.563; observer 2, τ = 0.456), FIGO stage (observer 1, τ = 0.354; observer 2, τ = 0.324), and prognostic risk classification (observer 1, τ = 0.456; observer 2, τ = 0.385). The area under the ROC curves of ADC OGSE /ADC PGSE for histological grade (observer 1, 0.92, 95% confidence intervals [CIs]: 0.83–0.98; observer 2, 0.84, 95% CI: 0.73–0.92) and prognostic risk (observer 1, 0.80, 95% CI: 0.68–0.89; observer 2, 0.76, 95% CI: 0.63–0.86) were significantly higher than that of ADC OGSE and ADC PGSE . Data Conclusion The ADC ratio obtained via oscillating gradient and pulsed gradient DWIs might be useful imaging biomarkers for risk stratification in patients with endometrial cancer. Level of Evidence 3 Technical Efficacy Stage 2