Measurement of uterine fibroid volume: a comparative accuracy and validation of methods study

A range of measurement techniques have been described which may be used to calculate uterine fibroid volume. A commonly-reported method involves application of a formula for the volume of an ellipsoid sphere to three orthogonal axes of a fibroid as measured on cross-sectional images. We aimed to compare this method and a second method, that of software-computed parallel planimetric uterine fibroid computation on MRI images, to a gold standard: the volume of objects measured by water displacement. We also compared these methods in volume estimation of patient fibroids using MRI data.

Mixed observational study and blinded cross-sectional analysis of imaging data.

Large inter-observer variability was noted when using the ellipsoid formula method, which was also inaccurate when compared to the gold standard. Conversely, the parallel planimetric method showed excellent interobserver correlation and a high degree of correlation with gold standard volume measurements.

We conclude that the parallel planimetric method, although a more complex and time consuming technique, is the more accurate and therefore preferred method for measuring uterine fibroid volume.