Loss of Contrast Intensity During Systole in the Left Ventricular Cavity with the Use of the Contrast Agent Albunex

Abstract

The video-intensity measurements were inversely and irreversibly related to ambient pressure changes (independent of velocity) in a tube model. However, video intensity varied inversely but reversibly with velocity (independent of pressure). This observation could not be explained simply by the "laminar flow" theory, by a change in transducer angulation, nor by a change in ultrasound imaging frame rate. This phenomenon was limited to Albunex microbubbles and was not observed with a contrast medium (corn starch) devoid of the acoustic properties of Albunex.

Improvement of Detection Sensitivity of Microbubbles as Sensors to Detect Ambient Pressure

“…To date, there are numerous reports about microbubbles as sensors for the local blood pressure measurements through detecting disappearance time of free bubbles [5,6], shift of the first harmonic or subharmonic resonance frequency [4,7,8,9,10,11,12], or amplitude variation of the scattered echo of microbubbles [1,3,10,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30]. Among them, amplitude variation of the scattered echo is most attractable and promising for clinical application.…”