title: Application of high-intensity focused ultrasound for umbilical artery occlusion in a rabbit model.
abstract: OBJECTIVE
  To investigate the application of high-intensity focused ultrasound (HIFU) for fetal umbilical artery blood flow occlusion in a rabbit model.
  
  
  METHODS
  A prototype HIFU transducer in combination with an imaging probe with Doppler capability was constructed. Using this transducer, HIFU was applied at 1.4, 2.75 or 5.5 kW/cm(2) through the maternal abdominal skin to the fetal intra-abdominal umbilical arteries of four time-mated Japanese White rabbits (11 fetuses) on gestational day 25. Courses of 5-s HIFU exposure were performed until cessation of umbilical blood flow and cardiac arrest were confirmed by Doppler ultrasonography. Fetal necropsy was performed and exposed lesions were assessed by microscopic histological analysis.
  
  
  RESULTS
  The mean diameter of the fetal umbilical artery was 0.6 +/- 0.2 mm and the mean peak systolic velocity of arterial blood flow was 44.7 +/- 18.5 cm/s. When HIFU was applied at 5.5 kW/cm(2), blood flow was completely occluded within 15 courses. HIFU exposure brought about vacuolar degeneration and destruction of elastic fibers in the tunica media of the artery.
  
  
  CONCLUSIONS
  HIFU can be used to occlude umbilical artery blood flow in fetal rabbits.
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, Showa University, Tokyo, Japan. ichizuka@med.showa-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Ichizuka
authors.forename: S
authors.initials: S
authors.lastname: Ando
authors.forename: M
authors.initials: M
authors.lastname: Ichihara
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: N
authors.initials: N
authors.lastname: Uchiyama
authors.forename: K
authors.initials: K
authors.lastname: Sasaki
authors.forename: S
authors.initials: S
authors.lastname: Umemura
authors.forename: R
authors.initials: R
authors.lastname: Matsuoka
authors.forename: A
authors.initials: A
authors.lastname: Sekizawa
authors.forename: T
authors.initials: T
authors.lastname: Okai
authors.forename: T
authors.initials: T
authors.lastname: Akabane
authors.forename: M
authors.initials: M
authors.lastname: Kushima
mesh_terms: D000818:Animals; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging* / Q000628:therapy; D001783:Blood Flow Velocity / Q000502:physiology; D005260:Female; D023421:Models, Animal; D011247:Pregnancy; D011817:Rabbits; D051381:Rats; D014464:Ultrasonic Therapy / Q000379:methods*; D016216:Ultrasonography, Prenatal / Q000379:methods*; D014469:Umbilical Arteries / Q000000981:diagnostic imaging* / Q000503:physiopathology