On the accuracy of optically tracked transducers for image-guided transcranial ultrasound
- 100 Downloads
Transcranial focused ultrasound (FUS) is increasingly being explored to modulate neuronal activity. To target neuromodulation, researchers often localize the FUS beam onto the brain region(s) of interest using spatially tracked tools overlaid on pre-acquired images. Here, we quantify the accuracy of optically tracked image-guided FUS with magnetic resonance imaging (MRI) thermometry, evaluate sources of error and demonstrate feasibility of these procedures to target the macaque somatosensory region.
We developed an optically tracked FUS system capable of projecting the transducer focus onto a pre-acquired MRI volume. To measure the target registration error (TRE), we aimed the transducer focus at a desired target in a phantom under image guidance, heated the target while imaging with MR thermometry and then calculated the TRE as the difference between the targeted and heated locations. Multiple targets were measured using either an unbiased or bias-corrected calibration. We then targeted the macaque S1 brain region, where displacement induced by the acoustic radiation force was measured using MR acoustic radiation force imaging (MR-ARFI).
All calibration methods enabled registration with TRE on the order of 3 mm. Unbiased calibration resulted in an average TRE of 3.26 mm (min–max: 2.80–4.53 mm), which was not significantly changed by prospective bias correction (TRE of 3.05 mm; 2.06–3.81 mm, p = 0.55). Restricting motion between the transducer and target and increasing the distance between tracked markers reduced the TRE to 2.43 mm (min–max: 0.79–3.88 mm). MR-ARFI images showed qualitatively similar shape and extent as projected beam profiles in a living non-human primate.
Our study describes methods for image guidance of FUS neuromodulation and quantifies errors associated with this method in a large animal. The workflow is efficient enough for in vivo use, and we demonstrate transcranial MR-ARFI in vivo in macaques for the first time.
KeywordsFocused ultrasound Ultrasound neuromodulation Optical tracking Image-guided therapy Neuromodulation
This work was funded by National Institutes of Health Grants 5T32EB014841, R24 MH109105, and the Focused Ultrasound Foundation. We would also like to acknowledge expert assistance from George Wilson and Chaohui Tang for animal handling support and Tom Manuel for assistance with computer-aided design.
Compliance with ethical standards
Conflict of interest
All authors declare that they have no conflict of interest.
- 3.Mestas JL, Fowler RA, Evjen TJ, Somaglino L, Moussatov A, Ngo J, Chesnais S, Rognvaldsson S, Fossheim SL, Nilssen EA, Lafon C (2014) Therapeutic efficacy of the combination of doxorubicin-loaded liposomes with inertial cavitation generated by confocal ultrasound in AT2 dunning rat tumour model. J Drug Target 22:688–697. https://doi.org/10.3109/1061186X.2014.906604 CrossRefGoogle Scholar
- 11.Hynynen K, Clement GT, McDannold N, Vykhodtseva N, King R, White PJ, Vitek S, Jolesz FA (2004) 500-Element ultrasound phased array system for noninvasive focal surgery of the brain: a preliminary rabbit study with ex vivo human skulls. Magn Reson Med 52:100–107. https://doi.org/10.1002/mrm.20118 CrossRefGoogle Scholar
- 13.Savic LJ, De Lin M, Duran R, Schernthaner RE, Hamm B, Geschwind J-F, Hong K, Chapiro J (2015) Three-dimensional quantitative assessment of lesion response to MR-guided high-intensity focused ultrasound treatment of uterine fibroids. Acad Radiol. https://doi.org/10.1016/j.acra.2015.05.008 Google Scholar
- 14.King RL, Brown JR, Pauly KB (2014) Localization of ultrasound-induced in vivo neurostimulation in the mouse model. Ultrasound Med Biol 40:1512–1522. https://doi.org/10.1016/j.ultrasmedbio.2014.01.020 CrossRefGoogle Scholar
- 16.Ye PP, Brown JR, Pauly KB (2016) Frequency dependence of ultrasound neurostimulation in the mouse brain. Ultrasound Med Biol. https://doi.org/10.1016/j.ultrasmedbio.2016.02.012 Google Scholar
- 25.Lindseth F et al (2013) Ultrasound-based guidance and therapy. In: Advancements and breakthroughs in ultrasound imaging. IntechOpen. https://doi.org/10.5772/55884
- 30.Conley RH, Meszoely IM, Weis JA, Pheiffer TS, Arlinghaus LR, Yankeelov TE, Miga MI (2015) Realization of a biomechanical model-assisted image guidance system for breast cancer surgery using supine MRI. Int J Comput Assist Radiol Surg 10:1985–1996. https://doi.org/10.1007/s11548-015-1235-9 CrossRefGoogle Scholar
- 35.Jonathan S, Phipps MA, Chaplin VL, Singh A, Yang PF, Newton AT, Gore JC, Chen LM, Caskey CF, Grissom WA (2018) Optical tracking-guided MR-ARFI for targeting focused ultrasound neuromodulationin non-human primates. In: Grissom WA, Caskey CF (eds) In The 18th international society of therapeutic ultrasound, pp 176–178. NashvilleGoogle Scholar