Transpulmonary Transit of Microbubbles During Contrast Echocardiography: Implications for Estimating Cardiac Output and Pulmonary Blood Volume

Galanti, Giorgio; Jayaweera, Ananda R.; Villanueva, Flordeliza S.; Glasheen, William P.; Ismail, Suad; Kaul, Sanjiv

doi:10.1016/s0894-7317(14)80063-1

Cited by 23 publications

(9 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Consequently, the resulting output function is not much different from the input function, 4 and this difference cannot be resolved by ultrasound. Thus, the measured myocardial output function invariably reflects the dispersion of bubbles in the large central circulation (and hence provides a measure of cardiac output 16 ) rather than the mean myocardial transit rate. 4 …”

Section: Limitations In Using Tracer Kinetics To Measure Myocardial Pmentioning

confidence: 99%

Quantification of Myocardial Blood Flow With Ultrasound-Induced Destruction of Microbubbles Administered as a Constant Venous Infusion

et al. 1998

Self Cite

View full text Add to dashboard Cite

Background-Ultrasound can cause microbubble destruction. If microbubbles are administered as a continuous infusion, then their destruction within the myocardium and measurement of their myocardial reappearance rate at steady state will provide a measure of mean myocardial microbubble velocity. Conversely, measurement of their myocardial concentration at steady state will provide an assessment of microvascular cross-sectional area. Myocardial blood flow (MBF) can then be calculated from the product of the two. Methods and Results-Ex vivo and in vitro experiments were performed in which either flow was held constant and pulsing interval (interval between microbubble destruction and replenishment) was altered, or vice versa. In vivo experiments were performed in 21 dogs. In group 1 dogs (nϭ7), MBF was mechanically altered in a model in which coronary blood volume was constant. In group 2 dogs (nϭ5), MBF was altered by direct coronary infusions of vasodilators. In group 3 dogs (nϭ9), non-flow-limiting coronary stenoses were created, and MBF was measured before and after the venous administration of a coronary vasodilator. In all experiments, microbubbles were delivered as a constant infusion, and myocardial contrast echocardiography was performed using different pulsing intervals. The myocardial video intensity versus pulsing interval plots were fitted to an exponential function: yϭA(1Ϫe Ϫ␤t ), where A is the plateau video intensity reflecting the microvascular cross-sectional area, and ␤ reflects the rate of rise of video intensity and, hence, microbubble velocity. Excellent correlations were found between flow and ␤, as well as flow and the product of A and ␤. Conclusions-MBF can be quantified with myocardial contrast echocardiography during a venous infusion of microbubbles.This novel approach has potential for measuring tissue perfusion in any organ accessible to ultrasound. (Circulation. 1998;97:473-483.)

show abstract

Section: Limitations In Using Tracer Kinetics To Measure Myocardial Pmentioning

confidence: 99%

Quantification of Myocardial Blood Flow With Ultrasound-Induced Destruction of Microbubbles Administered as a Constant Venous Infusion

et al. 1998

Self Cite

View full text Add to dashboard Cite

show abstract

“…These are used to enhance the scattering of ultrasound from blood and hence as echo-enhancing or contrast agents, due to the large difference in acoustic impedance between the gas in the bubbles and surrounding blood [McDiken and Hoskins, 2000]. It is used to measure cardiac output [Mulvagh et al, 2000], in dobutamine (a vasodilator) stress echocardiography [Galanti et al, 1993], fallopian tube potency [Wible, 1994], vesicoureteral reflux (a common pediatric urinary tract abnormality), and detection of thrombus [Bach, 1999]. It consists of air-filled albumin MS with a mean diameter of 3-5 mm, with usual concentration of 3-5 Â 10 8 microspheres per mL in nonpyrogenic sterile isotonic solution buffered adjusted to pH 6.4-7.4 [Church et al, 1993].…”

Section: Uses Diagnostic Purposesmentioning

confidence: 99%

“…The wall thickness of the encapsulating shell of albumin is estimated to be around 15 nm. Its refrigeration shelf-life is around 1 year [Galanti et al, 1993]. Typically, the lifetime in blood ranges from 2-3 min and up to 20-30 min [McDiken and Hoskins, 2000].…”

Section: Uses Diagnostic Purposesmentioning

confidence: 99%

Biopolymer albumin for diagnosis and in drug delivery

Patil¹

2003

Drug Development Research

152

View full text Add to dashboard Cite

This article reviews the developmental stages and strategies used to assess the biomedical utility of biopolymer albumin from the 1970s to early 2002. The basic method and mechanism(s) of preparation of albumin microspheres and subsequent modifications made to overcome the drawbacks of earlier approaches and the need for further developments are discussed, as are the processing parameters and the level of various ingredients affecting the physicochemical properties of the albumin microspheres. Different equations proposed by various investigators to modulate in vitro release kinetics are reviewed. The microscopic structural and surface properties, the chemical modification of the biopolymer (e.g., cationization, tagging with amino acids and sugar moieties) for tissue specificity or to influence the release profile and biodegradation are discussed. An array of potential diagnostic applications and the use of albumin microspheres as a drug delivery system are reviewed. Drug Dev.

show abstract

“…For example, if the centroid of a renal vein time-signal curve was 15 s and that of a renal artery 10 s, the renal MTT would be 5 s. This type of approach was attempted in the dog heart with Albunex, but self-shadowing artifact limited its application (GALANTI et al 1993). In other words, if a time-enhancement curve is calculated for a parenchymal region of interest, the centroid of this curve represents the "average" enhancement time in that area.…”

Section: Temporal Indices Using Passive Modesmentioning

confidence: 99%