Computer Assisted Medical Interventions

EchoTrack – ultrasound navigation for percutaneous needle insertions

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Computer guidance has become increasingly important for assisting procedures in modern patient care. This is attributed to a number of expected benefits compared to conventional approaches, including increased accuracy, reduction of complications and decreased intervention time. Despite the fact that these benefits have been shown in various studies, not many guidance systems have found their way into clinical practice, yet, which is mainly attributed to the difficulty of integrating such approaches into established clinical workflows, the lack of accuracy, reliability and robustness, and often high additional costs.


With “EchoTrack” a new concept is proposed that allows assisting ultrasound (US)-guided needle insertions while maintaining the established clinical workflow. The basic idea is to integrate a small electromagnetic (EM) tracking system with an US probe in one single device to enable simultaneous real-time localization of patient and instrument [1]. Compared to existing guidance approaches EchoTrack features the following key advantages: (1) No additional external hardware is required as tracking and imaging is provided by the proposed handheld device. (2) Combining EM tracking with the US imaging ensures that the area of highest tracking accuracy and robustness always coincides with the imaging area [2,3].

Conventional US-guided needle insertions

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Ultrasound-guided needle insertions are usually performed in-plane such that the needle is visible in the US image. Freehand punctures are thus difficult to perform in particular for inexperienced operators. Needle guides ensure good needle visibility but restrict the movement of probe and needle.

EchoTrack Concept

Combining the field generator of an electromagnetic tracking system with an US probe allows US imaging and instrument localization within one device. The EchoTrack solution provides augmentation of the US image with current information on the needle location, the needle insertion trajectory, the position of the target, and critical structures.

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Clinical applications

Radiofrequency ablation (RFA) of thyroid nodules

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In collaboration with the Department of Nuclear Medicine at the University Hospital Frankfurt (Prof. H. Korkusuz, Prof. F. Grünwald), the EchoTrack concept has been adapted to provide guidance during radiofrequency ablations of thyroid nodules. Adaptation included the combination of the EM field generator with a linear US probe used for these interventions and construction of a customized sensor carrier to allow localization of the RFA needle. A preclinical study showed that the EchoTrack approach can significantly reduce the number of needle redirections compared to the conventional approach [4]. The EchoTrack approach could also be successfully applied in a first clinical case [5].

Punctures of abdominal lesions

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Punctures of abdominal targets for diagnostic or therapeutic purposes are among the most commonly performed needle insertions. Initially intended to assist such interventions, the EchoTrack approach was applied and evaluated for hepatic [6] and renal [7] punctures in ex-vivo animal models. This work is conducted in close collaboration with the Department of Surgery at the University Hospital Heidelberg (PD Dr. D. Teber, Dr. T. Simpfendörfer)

Clinical translation

Current development aims for a translation of the EchoTrack concept towards clinical routine. In a first step, a clinical prototype is developed following a quality centered development process. Open questions concern accuracy, robustness, and usability of the prototype and involve development of methods for error reduction and calibration as well as investigation of user experience prior to conducting a comprehensive clinical study.

Key collaborators

  • Department of Nuclear Medicine, University Hospital Frankfurt

  • Department of Urology, University Hospital Heidelberg

  • Department of General, Visceral and Transplant Surgery, University Hospital Heidelberg

Selected publications

  1. Franz AM, Seitel A, Bopp N, Erbelding C, Cheray D, Delorme S, et al. First clinical use of the EchoTrack guidance approach for radiofrequency ablation of thyroid gland nodules. Int J Comput Assist Radiol Surg. 2017 Jun;12(6):931–40.

  2. Erbelding C, Franz A, Seitel A, Bopp N, Kohlhase K, Grünwald F, et al. Ultrasound-navigated radiofrequency ablation of thyroid nodules with integrated electromagnetic tracking: comparison with conventional ultrasound guidance in gelatin models. Int J Comput Assist Radiol Surg. 2017 Sep;12(9):1635–42.

  3. Simpfendörfer T, Franz AM, Gasch C, Maier-Hein L, Hohenfellner M, Teber D. Sonongraphisch Navigierte Nierenpunktion unter Verwendung eines mobilen Elektromagnetischen Trackingsystems. In: Urologie. 2016. p. 51. (Suppl 1; vol. 55).

  4. Franz AM, Simpfendörfer T, Garoussi C, Majlesara A, März K, Meinzer H-P, et al. Echotrack for simulataneous EM tracking and US imaging: initial experience in ventilated swine cadaver. In: International Journal of Computer Assisted Radiology and Surgery. 2015. p. 52. (Suppl 1; vol. 10).

  5. März K, Franz AM, Seitel A, Winterstein A, Hafezi M, Saffari A, et al. Interventional real-time ultrasound imaging with an integrated electromagnetic field generator. Int J Comput Assist Radiol Surg. 2014 Sep;9(5):759–68.

  6. Franz AM, Haidegger T, Birkfellner W, Cleary K, Peters TM, Maier-Hein L. Electromagnetic tracking in medicine—a review of technology, validation, and applications. IEEE Trans Med Imaging. 2014;33(8):1702–1725.

  7. Franz AM, März K, Hummel J, Birkfellner W, Bendl R, Delorme S, et al. Electromagnetic tracking for US-guided interventions: standardized assessment of a new compact field generator. Int J Comput Assist Radiol Surg. 2012 Nov;7(6):813–8.

Awards

  • IPCAI Bench to Bedside Award (2017)
    Alfred Franz et al., for the paper, "First clinical use of the EchoTrack guidance approach for radiofrequency ablation of thyroid gland noules."

  • conhIT-Nachwuchspreis (2017)
    Dominique Cheray, for the best Bachelors thesis "Benutzerzentrierte Softwarekonzeption und Entwicklung einer Applikation zur ultraschall-navigierten perkutanen Punktion", awarded by conhIT
  • Presentation prize, 68th Congress of German urology association (2016)
    T. Simpfendörfer et al., "Sonographisch navigierte Nierenpunktion unter Verwendung eines mobilen elektromagnetischen Trackingsystems."

  • ISCAS Kikuchi Frugal Technology Award (2015)
    International Congress and Exhibition on Computer Assisted Radiology and Surgery (CARS)
    Alfred Franz et al., "Echotrack for simultaneous EM tracking and US imaging: initial experience in ventilated swine cadaver."

  • Fachbereichspreis for the best Master Thesis (2014)
    Adrian Winterstein, for Masters Thesis "Ein ultraschallbasiertes Computerassistenzsystem mit integriertem elektromagnetischem Feldgenerator für die Leberchirurgie: Konzeption und Realisierung im Rahmen von MITK", awarded by the University of Darmstadt

  • Thomas-Gessmann-Förderpreis (2013) 
    awarded by the Thomas Gessmann-Stiftung
    Keno März, for Master Thesis "Computer-Assistierte Punktionen unter Ultraschallführung mit einem mobilen elektromagnetischen Feldgenerator."

  • Best Scientific Work and Best poster (2013)
    Bildverarbeitung für die Medizin conference
    Keno März et al., "Navigierte ultraschallgeführte Leberpunktion mit integriertem EM Feldgenerator"

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