Three-dimensional CT reconstruction of the human skull used to assess the efficacy of transcranial ultrasound as a function of frequency, pulse duration, pulse repetition frequency and transducer orientation.

Signal backscattered from a suspension of liposomes in a latex container exposed to 3.5-MHz ultrasound pulses. The strong peaks to the extreme left and right of the waveform are the reflections from the latex walls of the chamber, whilst the portion of the signal in between those two peaks represents the scattering activity of the liposomes themselves.

Setup to measure echogenicity for stability studies of echogenic liposomes.

Echogenic liposomes on ultrasound image (Philips HDI 5000 ultrasound system, L12-5 transducer).

Anatomy of an echogenic liposome as postulated from preliminary data in our laboratory.

Ex vivo murine aortas treated with Rhodamine-labeled ELIP delivered via a proximal injection of Rh-ELIP into an intravascular flow of 0.5% BSA at 5.6 mL/min. A -C show an artery treated with Rh-ELIP alone, while D - F show an artery treated with a combination of Rh-ELIP and CW ultrasound (0.49 MPa peak to peak amplitude). Panels A and D show arteries stained with factor VIII to highlight the endothelium. Panels B and E show the arterial walls as viewed with a blue filter, superimposed over the same segment viewed with a red filter. Panels C and F show the red-filtered image alone, where the increased fluorescence in Panel F is due to the presence of Rhodamine. The full scale bar is 100 µm.

Three-dimensional CT reconstruction of the middle cerebral artery (MCA) emerging from the orbital shelf in a 31-year old female patient. The MCA is a common site for ischemic stroke and constitutes the focus of the Transcranial Ultrasound Thrombolysis System (TUTS).

Recent increases in the pressure output of diagnostic ultrasound scanners have led to an interest in establishing thresholds for bioeffects in many organs including the lungs of mammals. The thresholds of lung damage due to exposure to 6.0 MHz pulsed Doppler or color Doppler ultrasound have been determined in the Sprague-Dawley rat. In addition, the determination of the threshold of lung damage due to 6.75 MHz M-Mode pulses is in progress. Pathologic features of the damage include extravasation of erythrocytes into the alveolar spaces. The above Doppler image was recorded during insonification of a rat lung with a Doppler pulse at an MI of 1.8.

In order to quantify the ultrasound exposure conditions under which damage occurs, the ultrasonic pressure field was measured near ex vivo, aerated rat lung in a water bath. The pressure output of the ATL L10-5 linear array was interrogated near the lung with a Sonic Technologies 0.4-mm bilaminar membrane-type PVDF hydrophone. The above image of the Peak-to-Peak acoustic pressure output of the 6.0 MHz Doppler pulse in the free field focus was created in LabView. Compare with the image below, which reveals the pressure output acquired in with an inflated ex vivo rat lung in the focus of the same scanhead. Note the 50% increase in the peak acoustic output with the inflated lung present in the field (which acts like an acoustic pressure release surface).

Alignment of 30 MHz Active Cavitation Detector with ATL L10-5 scanhead.

Active Cavitation Detector Electronics.