Student Work

Development of a Needle Insertion System for Ultrasound-Guided PCNL

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This work aimed to develop a needle insertion system designed to ensure the needle and the ultrasound image are aligned in-plane, significantly improving the accuracy in ultrasound-guided percutaneous nephrolithotomy (PCNL). Current techniques require coordination between the probe and needle out of the plane, which can be challenging. This issue was addressed by using an acoustic reflector and optimal materials that match the acoustic impedance of the probe and contact tissue. Additionally, the system includes a needle visualization algorithm for real-time visualization. The paper focuses on the development and testing of the system, with experimental results demonstrating the feasibility and effectiveness of the approach. The modular device has several components. The housing model holds an acoustic reflector, a needle arm holder, and a probe holder. Material optimization was determined by utilizing the acoustic impedance formula and modifying the equations to determine ideal impedance values for multiple correlated layers. The experimental value for the probe head (~1.9 MRayl) was used to calculate the theoretical impedances: 1.763-1.676 MRayl for the liquid medium, and 1.626-1.586 MRayl for the solid layer. Several highly accessible liquids and solids were chosen for material selection and testing. Images were evaluated using contrast to noise ratio (CNR) analysis to compare material(s) performance. To extract needle geometry and estimate its tip, a custom image processing algorithm was employed that utilized Gabor filters, morphological operations, advanced thresholding, and Hough transformations. Any probe can be adapted to the physical model by changing the front plate mold. After analyzing the CNR values, the team identified latex (~1.5 MRayls) and water-glycerin mix (~1.7 MRayls) as the optimal combination due to having the highest average score of 4.58, being the closest to the ground truth value of 5.46. The final prototype image was compared to a ground truth image during a CIRS phantom test, showing similar results and confirming the effectiveness of optimized material selection. A gelatin phantom and water tank test showed the potential of the algorithm identifying the needle tip, providing in-plane needle visualization.

  • This report represents the work of one or more WPI undergraduate students submitted to the faculty as evidence of completion of a degree requirement. WPI routinely publishes these reports on its website without editorial or peer review.
  • E-project-042423-164313
  • 104681
  • 2023
UN Sustainable Development Goals
Date created
  • 2023-04-24
Resource type
  • E-project-042423-164313
Rights statement
Last modified
  • 2023-06-22


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