Volume measurement of intraocular tumours by cross-sectional ultrasonographic scans

The volume of intraocular tumours can be calculated from tumour height and cross-sectional areas measured in maximal orthogonal B-mode ultrasonograms, on the assumption that the tumour morphology is hemi-ellipsoidal. Comparison of this method with an accurate but more complex computer-aided B-mode ultrasonic tomographic method demonstrated a highly linear relationship with a correlation coefficient of 0.93. Furthermore, the comparison of cross-sectional areas measured from B-scan images and histological cross-sections in a small series of enucleated eyes demonstrated that tumour cross-sectional area measured from ultrasound images provides an accurate representation of the true physical size of the tumour in the globe. This method can be easily implemented with readily available B-mode ultrasound equipment. Unlike previously reported volume measurement methods, customised hardware or software is not required. The method is rapid and easy to perform, and may offer a useful standard method of measuring and monitoring intraocular tumours.