Evaluating Electromagnetic Guidance for Fine Needle Aspiration in a Thyroid-like Ultrasound Phantom

Ziel/Aim Technical success of thyroid punctures can be limited by anatomical constraints and operator-dependency. EchoTrack is a novel compact guidance solution for existing ultrasound transducers allowing 2D and 3D visualization of needle insertion paths during ultrasound-assisted thyroid interventions. This pilot study evaluates feasibility of fine needle aspiration (FNA) aided by EchoTrack guidance in a dedicated thyroid puncturing model.

Methodik/Methods A thyroid-like phantom was designed to mimic puncture geometry for 8 target lesions (15x6 mm oil capsules) and an analogue for tracheal sparing embedded in ballistic gelatin. The guidance solution was adapted for thyroid biopsies, consisting of a miniature electromagnetic (EM) field generator mounted on a linear ultrasound probe, an EM-sensor attached to a syringe holder, and the EM tracking system.

Four right-sided and four left-sided punctures were performed using both in-plane and multiangle out-of-plane techniques. EchoTrack was used for two punctures on each side. Time-to-target, number of redirection attempts (needle withdrawal in case of initial mispositioning) and subjective feedback were documented. Operators were grouped by their levels of experience in FNA: 5 with less than 50 FNAs performed, 3, with 50 to 100 FNAs and 3 with more than 100 FNAs.

Ergebnisse/Results Eighty-eight target lesions were punctured by 11 operators. Out-of-plane punctures were performed significantly faster than in-plane punctures (7.1 s vs. 17.6 s, p = 0.002). EchoTrack decreased median time-to-target in out-of-plane punctures from 9.8 s to 4.8 s (p = 0.001), with the most marked effect in the least experienced user group. Repositioning attempts were reduced in out-of-plane punctures (p = 0.026) and subjective feedback was improved (p = 0.019).

Schlussfolgerungen/Conclusions EchoTrack guidance shows a significant benefit for multiangle out-of-plane puncturing approaches, by reducing intervention time, repositioning attempts and improving subjective user experience in a thyroid-like puncturing model.