Feasibility of a Reduced Field-of-View Diffusion-Weighted (rFOV) Sequence in Assessment of Myometrial Invasion in Patients With Clinical FIGO Stage I Endometrial Cancer

Purpose: To compare the clinical usefulness of reduced field-of-view diffusion-weighted imaging (rFOV) with other imaging techniques in determining the depth of myometrial invasion (DMI) in endometrial cancer. Materials and Methods: In this prospective study we reviewed 3T magnetic resonance images of 51 patients with clinical Stage I endometrial cancer who underwent total abdominal hysterectomy with bilateral salphingoopherectomy within 3 days after imaging. rFOV with apparent diffusion coefficient reconstruction was obtained in three standard planes followed by sagittal T2-weighted (T2WI) images and 3D dynamic T1-weighted and contrast-enhanced imaging (DCE MRI). Two radiologists with expertise in imaging gynecologic cancers evaluated images independently. The DMI was recorded on imaging and correlated with surgical pathology results. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for DMI were calculated (<50% vs. >50%). Results: Compared with sagittal T2WI+DCE MRI, rFOV imaging yielded greater specificity (82.2% vs. 90.0%, positive predictive value (42.8% vs. 60.0%), and accuracy (84.0% vs. 92%) for DMI determined by reader 1 and greater the sensitivity (83.3% vs. 100%) for DMI determined by reader 2. The error of measurement of DMI as a continuous variable in millimeters did not differ significantly between the rFOV and pathology results (P < 0.21). However, there was a statistically significant difference for the DMI measured on the dynamic sequence. The DMI on DCE was greater than that seen on pathology at P=0.02. Conclusion: rFOV can be used to assess DMI in clinical Stage I endometrial cancer.