title: Measurement of radial artery contrast intensity to assess cardiac microbubble behavior.
abstract: OBJECTIVE
  We sought to determine whether analysis of the contrast signal from the radial artery is better able to reflect changes in left ventricular (LV) microbubble dynamics than the signal from the LV itself.
  
  
  BACKGROUND
  Assessment of microbubble behavior from images of the LV may be affected by attenuation from overlying microbubbles and nonuniform background signal intensities. The signal intensity from contrast in a peripheral artery is not affected by these artifacts and may, thus, be more accurate.
  
  
  METHODS
  After injection of a contrast bolus into a peripheral vein, signal intensity was followed simultaneously in the LV and radial artery. The measurements were repeated using continuous, triggered, low and high mechanical index harmonic imaging of the LV.
  
  
  RESULTS
  Peak and integrated signal intensities ranged from 25 dB and 1550 dB/s, respectively, with radial artery imaging to 5.6 dB and 471 dB/s with ventricular imaging. Although differences in microbubble behavior during the different imaging protocols could be determined from both the LV and radial artery curves, analysis of the radial artery curves yielded more consistent and robust differences.
  
  
  CONCLUSIONS
  The signal from microbubbles in the radial artery is not affected by shadowing and is, thus, a more accurate reflection of microbubble behavior in the LV than the signal from the LV itself. This may have important implications for the measurement of myocardial perfusion by contrast echocardiography.
authors.affiliation: Cardiac Ultrasound laboratory, Massachusetts Genral Hospital, Harvard Medical School, Boston, 02114, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Sosnovik
authors.forename: James L
authors.initials: JL
authors.lastname: Januzzi
authors.forename: Charles C
authors.initials: CC
authors.lastname: Church
authors.forename: Judith A
authors.initials: JA
authors.lastname: Mertsch
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Sears
authors.forename: Robert C
authors.initials: RC
authors.lastname: Fetterman
authors.forename: Richard C
authors.initials: RC
authors.lastname: Walovitch
authors.forename: Michael H
authors.initials: MH
authors.lastname: Picard
mesh_terms: D000418:Albumins; D003287:Contrast Media; D018618:Echocardiography, Doppler, Color; D005466:Fluorocarbons; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008863:Microspheres; D017534:Radial Artery / Q000000981:diagnostic imaging*; D018615:Ultrasonography, Doppler, Color; D016277:Ventricular Function, Left
chemical_list: D000418:Albumins; D003287:Contrast Media; C099458:FS 069; D005466:Fluorocarbons