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Ultrasound-Guided Needle Technique Accuracy: Prospective Comparison of Passive Magnetic Tracking Versus Unassisted Echogenic Needle Localization
  1. Angela N. Johnson, MSE, PMP, RAC*,,
  2. Jeffery S. Peiffer, BS,
  3. Nahi Halmann, PhD,
  4. Luke Delaney, MA,
  5. Cindy A. Owen, RT, RDMS, RVT and
  6. Jeff Hersh, MD, PhD§
  1. *Department of Technical Communication, Science & Healthcare, Texas Tech University, Lubbock, TX
  2. GE Healthcare, Technology and Medical Innovation Organization, Waukesha
  3. GE Healthcare, Ultrasound Business, Wauwatosa
  4. §GE Healthcare, Medical Affairs, Waukesha, WI
  1. correspondence: Angela N. Johnson, MSE, PMP, RAC, 3000 N Grandview Blvd, Waukesha, WI 53188 (e-mail: Angela.Johnson{at}


Background and Objectives Ultrasound-guided regional anesthesia facilitates an approach to sensitive targets such as nerve clusters without contact or inadvertent puncture. We compared accuracy of needle placement with a novel passive magnetic ultrasound needle guidance technology (NGT) versus conventional ultrasound (CU) with echogenic needles.

Methods Sixteen anesthesiologists and 19 residents performed a series of 16 needle insertion tasks each, 8 using NGT (n = 280) and 8 using CU (n = 280), in high-fidelity porcine phantoms. Tasks were stratified based on aiming to contact (target-contact) or place in close proximity with (target-proximity) targets, needle gauge (no. 18/no. 22), and in-plane (IP) or out-of-plane (OOP) approach. Distance to the target, task completion by aim, number of passes, and number of tasks completed on the first pass were reported.

Results Needle guidance technology significantly improved distance, task completion, number of passes, and completion on the first pass compared with CU for both IP and OOP approaches (P ⩽ 0.001). Average NGT distance to target was lower by 57.1% overall (n = 560, 1.5 ± 2.4 vs 3.5 ± 3.7 mm), 38.5% IP (n = 140, 1.6 ± 2.6 vs 2.6 ± 2.8 mm), and 68.2% OOP (n = 140, 1.4 ± 2.2 vs 4.4 ± 4.3 mm) (all P ⩽ 0.01). Subgroup analyses revealed accuracy gains were largest among target-proximity tasks performed by residents and for OOP approaches. Needle guidance technology improved first-pass completion from 214 (76.4%) per 280 to 249 (88.9%) per 280, a significant improvement of 16.4% (P = 0.001).

Conclusions Passive magnetic NGT can improve accuracy of needle procedures, particularly among OOP procedures requiring close approach to sensitive targets, such as nerve blocks in anesthesiology practice.

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  • Funding for this study was provided by GE Healthcare, Wauwatosa, WI, through the GE Healthcare Ultrasound Business operating in partnership with C. R. Bard, Inc. The Pinpoint GT needle guidance technology is used under license from C. R. Bard, Inc.

    Initial findings of this study were presented as an abstract at the 2016 American Association of Physicists in Medicine annual conference, July 31–August 3, 2016, Washington, DC.

    The authors who participated in the conduct of this research and drafted the manuscript are employees or contractors of GE Healthcare. The opinions and information presented herein are solely those of the authors. All practitioners performing needle tasks for this study were recruited from independent sites and not affiliated with GE Healthcare.

    This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.