title: Transcutaneous interruption of ultrasound contrast agents for blood flow evaluation.
abstract: OBJECTIVE
  The ability to create short boluses in targeted arteries with rapid rise times is limited by the transport of bubbles from the venous to arterial portion of the circulation. Acoustic interruption of contrast agent in arteries may create the short boluses necessary for simple wash-in/wash-out measures of blood flow.
  
  
  METHODS
  An ultrasound contrast agent was used with spectral Doppler ultrasound to observe contrast interruption in femoral arteries and VX2 carcinoma in a rabbit model. At an upstream location in the femoral artery, single, sinusoidal ultrasound tone bursts at 1.8 MHz with durations of 0.25 to 1 seconds were applied to interrupt the flow of contrast agent injected intravenously.
  
  
  RESULTS
  In VX2 carcinoma, bursts as short as 40 cycles produced contrast interruption lasting only one cardiac cycle within the tumor periphery and I(SPPA) <3 W/cm2 produced measurable interruptions.
  
  
  CONCLUSIONS
  Acoustic fields applied transcutaneously interrupted flow of contrast agents to form temporally short negative boluses.
authors.affiliation: University of Michigan Health Systems, Department of Radiology, Ann Arbor 48109-0553, USA. fowlkes@umich.edu
authors.forename: J B
authors.initials: JB
authors.lastname: Fowlkes
authors.forename: D W
authors.initials: DW
authors.lastname: Sirkin
authors.forename: J A
authors.initials: JA
authors.lastname: Ivey
authors.forename: E A
authors.initials: EA
authors.lastname: Gardner
authors.forename: R T
authors.initials: RT
authors.lastname: Rhee
authors.forename: J M
authors.initials: JM
authors.lastname: Rubin
authors.forename: P L
authors.initials: PL
authors.lastname: Carson
mesh_terms: D000818:Animals; D002277:Carcinoma / Q000000981:diagnostic imaging; D003287:Contrast Media / Q000008:administration & dosage; D004337:Drug Carriers; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging* / Q000502:physiology; D005466:Fluorocarbons / Q000008:administration & dosage; D007262:Infusions, Intravenous; D008081:Liposomes; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging; D011817:Rabbits; D012039:Regional Blood Flow; D012984:Software; D013848:Thigh; D013997:Time Factors; D018615:Ultrasonography, Doppler, Color / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data
chemical_list: D003287:Contrast Media; D004337:Drug Carriers; D005466:Fluorocarbons; D008081:Liposomes; C042852:perflutren