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 perfluorocarbonexposed sonicated dextrose albumin in fragmenting left circumflex coronary thrombotic occlusions. Results. In the in vitro model, both transcranial 1-MHz and 40-kHz ultrasonic frequencies were effective at fragmenting thrombi only in the presence of microbubbles. In the in vivo model, 1-MHz ultrasound with intravenous perfluorocarbon-exposed sonicated dextrose albumin angiographically recanalized only 4 of 14 occlusions but was consistently effective at improving myocardial blood flow to the risk area even in the absence of angiographic recanalization. Both 40-kHz and 1-MHz ultrasound with perfluorocarbon-exposed sonicated dextrose albumin improved regional wall-thickening and electrocardiographic abnormalities (P < .05 compared with control or ultrasound alone). Conclusions. Transcranial and transthoracic ultrasound in the presence of intravenous microbubbles can improve flow to ischemic regions and should be considered as a supplement to current pharmacologic therapy.
ASJC Scopus subject areas
- Radiological and Ultrasound Technology
- Radiology Nuclear Medicine and imaging