[home] [Personal Program] [Help]

---

Session: Poster session II
Session starts: Thursday 24 January, 16:00

---

Nick van de Berg (Delft University of Technology)
John van den Dobbelsteen (Delft University of Technology)

Abstract:
Approximately 70% of interventional radiologists experience difficulties in percutaneous lesion targeting as a result of poor needle visibility in ultrasound images [1]. Visibility may be limited by acute needle insertion angles, inadequate image plane alignments, echogenic surrounding tissues, and imaging artefacts, such as reverberations, comet tails, or shadowing effects. Numerous techniques have been proposed to enhance needle visibility by either changing the imaging method or the needle itself, e.g. beam steering, spatial compound imaging, echogenic coatings, and surface scoring or denting. Needle visibility is typically addressed by observations and subjective ratings. In contrast, this work proposes an objective and methodical quantification method to determine and compare the efficacy of needle visibility enhancement techniques. An automated image acquisition and analysis approach is proposed to efficiently collect and summarize large amounts of needle visibility data. Image processing included filtering, line fitting and image intensity analyses. A contrast-to-noise ratio and signal ratio were used to measure needle visibility and echogenicity, respectively. The approach was evaluated in PVA, in a comparative study of commercially available needles, as well as custom-made needles with grooves that resemble compliant joints of steerable needles. Distinct visibility peaks were seen at the 90° needle insertion angle, when specular reflections returned to the US transducer. Bevelled (chiba) and diamond (trocar) needle tips had a high visibility for a large angular range, compared to conical tips. The highest needle shaft visibility resulted from grooved needles, followed by trocar and shiba needles, respectively. Tip and shaft visibility in ultrasound images were compared for a near-full range (25-335°) of possible needle insertion angles. The shafts with grooves and the tips of trocar and chiba needles had the best performance. Overall, the presented approach provided an efficient and objective method to evaluate and compare needle visibility enhancement techniques. 1. de Jong, T.L., et al., Needle placement errors: do we need steerable needles in interventional radiology? Medical Devices-Evidence and Research, 2018. 11: p. 259-265.