Issues in 3-d Free-hand Medical Ultrasound Imaging

A drawback of conventional 2-D ultrasound imaging is the requirement that the physician mentally reconstruct 3-D anatomy given multiple 2-D image slices. This paper reviews attempts to overcome this problem using 3-D ultrasonic imaging. It is argued that free-hand imaging holds the most promise for e ective and inexpensive 3-D ultrasound. In the free-hand paradigm, the physician is allowed to move the probe freely over the region of interest, while a sensing device records the position of each scan. The set of 2-D scans and position data are subsequently used to construct a 3-D data set which can be rendered on a computer monitor or used for volumetric data analysis. In this paper the strengths and weaknesses of free-hand imaging are identi ed, with reference to sources of error in the measurement, reconstruction, visualisation and volumetric analysis processes. The ndings suggest several key research topics, aimed at overcoming some of the limitations of free-hand imaging.