title: The effect of ultrasound with acoustic radiation force on rabbit lung tissue: a preliminary study.
abstract: OBJECTIVE
  Acoustic radiation force (ARF) elastography has recently become available. The previous animal studies have revealed lung injuries induced by diagnostic ultrasound, but the effects on the lung resulting from exposure to ultrasound with ARF are unknown. This study aimed to assess the risk of lung injury associated with ultrasound with ARF.
  
  
  METHODS
  A focused 2.5-MHz transducer that emits ultrasound with ARF was used. A rabbit was anesthetized, and the transducer was placed in the right subcostal region. Exposure settings of mechanical index (MI) 0.80, pulse duration 10 ms, pulse repetition time 5 s, and exposure time 150 s were applied.
  
  
  RESULTS
  One red spot (7 × 6 mm) was observed on the surface of the right lung corresponding to the area of exposure. Alveolar hemorrhage was observed microscopically. This lesion was visible across a range of 20-170 μm in depth from the pleural surface.
  
  
  CONCLUSIONS
  The first example of lung hemorrhage induced by ultrasound with ARF was observed in this study. This observation suggests the possibility of lung injury in humans when ARF elastography is applied with the transducer directed toward the lung. Further studies are needed to determine the safety of this modality.
authors.affiliation: Department of Clinical Laboratory Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan. noriya.takkan@gmail.com.
authors.forename: Noriya
authors.identifier: http://orcid.org/0000-0002-7489-6159
authors.initials: N
authors.lastname: Takayama
authors.affiliation: Department of Surgery, Jichi Medical University, Shimotsuke, Tochigi, Japan.
authors.forename: Yasunao
authors.initials: Y
authors.lastname: Ishiguro
authors.affiliation: Department of Clinical Laboratory Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi, 329-0498, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Taniguchi
authors.affiliation: Medical Ultrasound Research Center, Doshisha University, Kyotanabe, Kyoto, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Akai
authors.affiliation: Department of Surgery, Jichi Medical University, Shimotsuke, Tochigi, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Sasanuma
authors.affiliation: Department of Surgery, Jichi Medical University, Shimotsuke, Tochigi, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Yasuda
authors.affiliation: Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan.
authors.forename: Naotaka
authors.initials: N
authors.lastname: Nitta
authors.affiliation: Medical Ultrasound Research Center, Doshisha University, Kyotanabe, Kyoto, Japan.
authors.forename: Iwaki
authors.initials: I
authors.lastname: Akiyama
mesh_terms: D000818:Animals; D054459:Elasticity Imaging Techniques / Q000009:adverse effects* / Q000379:methods; D006470:Hemorrhage / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D008168:Lung / Q000000981:diagnostic imaging / Q000473:pathology; D055370:Lung Injury / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D008297:Male; D011817:Rabbits; D000069453:Ultrasonic Waves / Q000009:adverse effects*; D014463:Ultrasonography / Q000009:adverse effects* / Q000379:methods
keywords: Acoustic radiation force; Elastography; Lung injury; Rabbit; Ultrasound