Objectives To determine whether endometrial volume or power Doppler indices as measured by three-dimensional (3D) ultrasound imaging can discriminate between benign and malignant endometrium or between endometrial hyperplasia and endometrial carcinoma. Also, comparing their diagnostic performance with that of endometrial thickness measurement using two-dimensional (2D) ultrasound examination, and to determine whether power Doppler indices add any diagnostic information to endometrial thickness or volume.
Methods Seventy-six patients with postmenopausal bleeding and endometrial thickness (ET) ≥ 5 mm underwent transvaginal 2D gray-scale and 3D power Doppler ultra- sound examination of the corpus uteri. The endometrial volume was calculated, along with the vascularization index (VI), flow index (FI) and vascularization flow index (VFI) in the endometrium. The ‘gold standard’ was the histological diagnosis of the endometrium obtained by hysteroscopic-guided biopsy. Receiver–operating characteristics (ROC) curves were drawn for all measurements to evaluate their ability to distinguish between benign and malignant endometrium and to differentiate between endometrial hyperplasia and endometrial carcinoma. Multivariate logistic regression analysis was used to create mathematical models to estimate the risk of endometrial malignancy.
Results There were 62 benign and 14 malignant endometria. Endometrial thickness and volume were significantly larger in malignant than in benign endometria, and flow indices in the endometrium was significantly higher. The area under the ROC curve (AUC) of endometrial thickness was 0.882, that of endometrial volume 0.850, and that of the two best power Doppler variables (VI and VFI in the endometrium) 0.904 and 0.932. The best logistic regression model for predicting malignancy contained the variables ET and VFI, with AUC 0.900. The mathematically optimal risk cut off value of ET and VFI 12.6 had sensitivity 78.57, specificity 93.55, +PV 67.7 and –PV 96.2. We also compared endometrial hyperplasia (29 cases) with endometrial carcinoma (14 cases). Endometrial thickness and volume were significantly larger in carcinoma than in endometrial hyperplasia, and flow indices in the endometrium were significantly higher. The area under the ROC curve (AUC) of ET was 0.897, that of endometrial volume 0.865, and that of the best power Doppler variables (VFI) was 0.941. The best logistic regression model for predicting malignancy contained the variables ET and VI, with AUC 0.921. The mathematically optimal risk cut off value of ET and VI 12 had sensitivity 78.57, specificity 96.55, +PV 79.7 and –PV 96.3.
Conclusions The diagnostic performance for discrimination between benign and malignant endometrium of 3D ultrasound imaging was not superior to that of endometrial thickness as measured by 2D ultrasound examination. Moreover, the diagnostic performance for discrimination between endometrial hyperplasia and endometrium carcinoma of 3D ultrasound imaging was not superior to that of endometrial thickness as measured by 2D ultrasound examination and 3D power Doppler imaging added little to endometrial thickness or volume.
|
