Effectiveness of transcranial and transthoracic ultrasound and microbubbles in dissolving intravascular thrombi.

Objective: To examine the effectiveness of 1 -MHz and 40-kHz ultrasound with and without microbubbles in fragmenting thrombi in attenuated conditions.

Methods: First, an vitro transcranial model was used to examine the ability of these frequencies to fragment thrombi in the presence or absence of perfluorocarbon-exposed sonicated dextrose albumin microbubbles. Second, an in vivo transthoracic model was used to test the effectiveness of these same frequencies with intravenous perfluorocarbon-exposed sonicated dextrose albumin in fragmenting left circumflex coronary thrombotic occlusions.

Real-time perfusion imaging with low mechanical index pulse inversion Doppler imaging.

Objectives: We sought to determine how successful pulse inversion Doppler (PID) imaging would be in detecting myocardial perfusion defects during dobutamine stress echocardiography.

Background: By transmitting multiple pulses of alternating polarity (PID) at a low mechanical index, myocardial contrast enhancement from intravenously injected microbubbles can be detected using real-time frame rates. Pulse inversion Doppler imaging was performed in 117 patients during dobutamine stress echocardiography by using an intravenous bolus of a perfluorocarbon-filled, albumin-(Optison: n = 98) or liposome- (Definity: n = 19) encapsulated microbubble and a mechanical index of <0.

Real-time assessment of myocardial perfusion and wall motion during bicycle and treadmill exercise echocardiography: comparison with single photon emission computed tomography.

Objectives: We sought to determine the feasibility and accuracy of real-time imaging of myocardial contrast echocardiography (MCE) in detecting myocardial perfusion defects during exercise echocardiography compared with radionuclide tomography.

Background: Ultrasound imaging at a low mechanical index and frame rate (10 to 20 Hz) after intravenous injections of perfluorocarbon containing microbubbles has the potential to evaluate myocardial perfusion and wall motion (WVM) simultaneously and in real time.

Methods: One hundred consecutive patients with intermediate-to-high probability of coronary artery disease underwent treadmill (n = 50) or supine bicycle (n = 50) exercise echocardiography.

Myocardial cavitational activity during continuous infusion and bolus intravenous injections of perfluorocarbon-containing microbubbles.

The 20-MHz component of broadband noise from inertial cavitation within the anterior myocardium of an open-chest dog was recorded during intravenous infusions or injections of perfluorocarbon-containing microbubbles during insonation with a 1.7-MHz harmonic transducer. Intramyocardial cavitational activity was evident even at a mechanical index of 0.

Inhibition of carotid artery neointimal formation with intravenous microbubbles.

Because therapeutic gene products such as synthetic antisense oligodeoxynucleotides (ODN) bind to albumin-coated microbubbles, we sought to determine whether IV perfluorocarbon-exposed sonicated dextrose albumin (PESDA) microbubbles could target their delivery to the carotid artery following balloon injury. In 5 pigs, the concentration of ODN taken up within the carotid vascular wall was found to be significantly increased when the IV antisense (ODN) was administered bound to PESDA (ODN-PESDA), and while transcutaneous low-frequency (20 kHz) ultrasound was applied over the carotid artery. Based on these results, a chronic model was then developed, in which 21 pigs received either IV ODN-PESDA, ODN alone, or control, following carotid balloon injury.