Quantification of power Doppler energy and its future potential.

Objective: To test a new software package (Color Quantifier, Kinetic Imaging, Liverpool, United Kingdom) that quantifies power Doppler energy and to determine its reproducibility.

Design: Intraobserver and interobserver reproducibility study.

Setting: University tertiary referral center.

Patient(s): Transvaginal power Doppler ultrasound images were recorded from women taking part in a study evaluating the physiological vascular changes in the uterus and ovaries during the normal menstrual cycle.

Intervention(s): Nineteen consecutive frames of regions of interest in the uterus, ovary, and follicle, respectively, were analyzed by each of four observers on 10 occasions.

Main Outcome Measure(s): Analysis of variance to determine the image and observer effect as well as the intraobserver and interobserver coefficients of variation.

Result(s): Significant image and observer effects were found. However, the image effect was by far the largest component of the total variation. The large image-to-image variability was expected because the cardiac cycle was included within the 19 frames (images) analyzed. The combined intraobserver and interobserver variation, expressed as the coefficients of variation, was found to be small for the above indices (as low as 1.9%), particularly for total ovary and endometrium.

Conclusion(s): The indices obtained with this color quantification software are reproducible in an in vitro setting using prerecorded images. Its applicability as a useful assay in the clinical setting requires further evaluation.