3D elastography using freehand ultrasound.

We present an elastography system using freehand 3D ultrasound. A review is provided of the standard elastography methods that have been adapted for this purpose. The scanning protocol is simple and promising results are presented of 3D strain images from freehand scans. Robustness is a problem, however, and the main sources of error are explained. Measures have been developed to improve the quality of the freehand images by means of drop-out correction and frame filtering. Results from the application of these techniques provide an indication of development strands which should lead to a system that is both easy-to-use and produces reliable, high quality images.