Endometrial volume and vascularity measurements by transvaginal three-dimensional ultrasonography and power Doppler angiography in stimulated and tumoral endometria: Intraobserver reproducibility

Abstract

Objectives. To assess intraobserver reproducibility of the endometrial volume (EV) and 3D power Doppler indices (vascularization index, VI; flow index, FI; and vascularization flow index, VFI) of the endometrium and subendometrial area using three-dimensional power Doppler angiography (3D-PDA). Methods. Twenty-five women on the hCG day after controlled ovarian stimulation and 15 patients presenting with uterine bleeding and suspicious endometrial thickening (10 endometrial cancers and 5 endometrial hyperplasias) were scanned. Eighty volume data sets were analyzed using the VOCAL imaging program. EV and VI, FI and VFI of the endometrium and subendometrium (5 mm shell) were manually calculated in the longitudinal and coronal planes with 15° and 9° rotation steps. Intraclass correlation coefficient (ICC) and 95% confidence intervals were used to assess reliability. Results. EV measurements were highly reproducible (ICC ≥ 0.97) without significant differences between planes and rotation steps. Endometrial and subendometrial VI, FI, and VFI presented ICCs above 0.90 with the exception of the subendometrial FI (ICC ≥ 0.80). There were no significant differences according to measurement plane and rotation step except for subendometrial VFI. Nevertheless, 3D power Doppler indices calculated in the coronal plane and 9° rotation step obtained the highest ICC. ICCs for 3D-PDA indices from the tumoral endometria were significantly higher than those calculated from the stimulated endometria. Conclusions. Endometrial volume and endometrial and subendometrial 3D power Doppler indices have an acceptable reproducibility, significantly higher in tumoral endometria. The reliability of measurements does not seem to be significantly influenced by the rotation plane and degrees of rotation. These results support that 3D-PDA and VOCAL are reliable methods to evaluate the physiological and pathological changes of the endometrium.