title: Pulsed application of focused ultrasound to the LI4 elicits deqi sensations: pilot study.
abstract: OBJECTIVE
  Focused ultrasound (FUS) techniques enable the delivery of acoustic pressure waves to a localized, specific region of anatomy, and mechanically stimulate the sonicated region when given in a train of pulses. The present pilot study examines if the pulsed application of acoustic waves focused to an acupuncture point (LI4, Hegu), i.e. FUS acupuncture, can elicit deqi sensations.
  
  
  METHODS
  The FUS was generated by a single-element ultrasound transducer, and delivered to the LI4 of acupuncture-naïve participants (n=10) for a duration of 1s using 2 ms tone-burst-duration and 50 Hz pulse repetition frequency. The subjective ratings of deqi descriptors were obtained across different conditions, i.e. FUS acupuncture using acoustic intensities of 1 and 3 W/cm(2) (spatial-peak temporal-averaged intensity, Ispta), sham sonication condition, tactile stimulation using a von Frey monofilament, and needle-based real and sham acupuncture. We also measured the presence of sharp pain, unpleasantness, and anxiety level during each condition.
  
  
  RESULTS
  The FUS acupuncture given at 3 W/cm(2) elicited deqi sensation ratings similar to those acquired during the needle-based acupuncture condition across the subjects, with significantly reduced levels of non-deqi related sensations, such as sharp pain, anxiety and unpleasantness. The lower acoustic intensity also generated deqi sensations, but at a lesser degree than the ones acquired using the higher acoustic intensity. Neither the sham conditions nor the tactile stimulation elicited deqi sensations.
  
  
  CONCLUSIONS
  The present data on acoustic acupuncture, with its exquisite spatial and depth control, along with the ability to electronically adjust its intensity, may suggest its potential utilization as an alternative mode of acupuncture, although further study is needed to probe its clinical efficacy.
authors.affiliation: Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA. Electronic address: yoo@bwh.harvard.edu.
authors.forename: Seung-Schik
authors.initials: SS
authors.lastname: Yoo
authors.affiliation: School of Nano-Bioscience & Chemical Engineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea.
authors.forename: Wonhye
authors.initials: W
authors.lastname: Lee
authors.affiliation: Center for Bionics, Korea Institute of Science and Technology, Seoul, Republic of Korea; Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: Hyungmin
authors.initials: H
authors.lastname: Kim
mesh_terms: D015669:Acupuncture Points; D015670:Acupuncture Therapy / Q000009:adverse effects / Q000379:methods / Q000523:psychology; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D010865:Pilot Projects; D012677:Sensation / Q000502:physiology; D013016:Sound; D014159:Transducers
keywords: Acupuncture; Alternative medicine; Neuromodulation; Ultrasound