Needle detection (Ultrasound)
Numerous interventions are performed under sonographic guidance, e.g. biopsies or placing catheters for brachytherapy. However, in ultrasound images needles and catheters are often poorly visible or seem visible, although being an artifact due to ill-focused ultrasound waves (see figure).
Structures can be detected, if either the frequency spectrum of ultrasound receive raw data – so-called A-lines - is exploited to propose additional classification parameters. Alternatively, automatic image analysis in 3-D and 3-D+t (4-D) ultrasound volumes allows an appropriate visualization.
The video on the left demonstrates how elevational artifacts impede visual detection of needles in 2-D and in 3-D ultrasound and that it can be overcome by automatic image volume analysis and needle modeling.