Myocardial and microcirculatory kinetics of BR14, a novel third-generation intravenous ultrasound contrast agent
Nicholas G. Fisher, MBBS*,
Jonathan P. Christiansen, MB, ChB*,
Howard Leong-Poi, MD*,
Ananda R. Jayaweera, PhD*,
Jonathan R. Lindner, MD* and
Sanjiv Kaul, MD*,*
* Cardiovascular Imaging Center, Cardiovascular Division, University of Virginia, Charlottesville, Virginia, USA
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Figure 1 Changes in acoustic intensity (AI) values from the left anterior descending coronary artery (LAD) and left circumflex coronary artery (LCx) beds (denoted on the images) after the injection of BR14 during maximal hyperemia. The LAD had a non-critical stenosis, whereas the LCx bed was normal. Although a flow mismatch is seen early after injection, the AI in both beds is similar at a later point in time, indicating redistribution. See text for details.
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Figure 2 Location and average numbers of stationary microbubbles per 20 high power optical fields (OF) over time. See text for details.
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Figure 3 Example of retained microbubbles within the capillaries under fluorescent epi-illumination. Microbubble (A) on the left of the picture remains static throughout the imaging sequence. A second microbubble (B) can be seen to stop in an adjacent capillary, remains virtually static for 4 s and then dislodges.
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Figure 4 A graphic representation of the temporal course of transient retention (arrival and departure times) of individual microbubbles in capillaries at x20 magnification. It can be seen that the microbubbles responsible for the acoustic signal at any given time are different.
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Figure 5 A mixing chamber model for the coronary circulation illustrating the input and output functions of a venous bolus injection of a second-generation contrast agent that is not retained within the myocardium. The input function resembles a Gaussian function, whereas the output function resembles a lagged normal density function. See text for details.
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figure 6 Time-versus-acoustic intensity plots of br14 from the left anterior descending coronary artery (lad) and left circumflex coronary artery beds in the presence of non-critical lad stenosis during hyperemia. the proposed model fits the plots from both the beds. see text for details. abbreviations as in figure 1.
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