Journal of Ultrasound in Medicine, Vol 20, Issue 12 1313-1325, Copyright © 2001 by American Institute of Ultrasound in Medicine
Effectiveness of transcranial and transthoracic ultrasound and microbubbles in dissolving intravascular thrombi
T. R. Porter, D. Kricsfeld, J. Lof, E. C. Everbach and F. Xie
Department of Internal Medicine, University of Nebraska Medical Center, Omaha 69198-1165, USA.
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. 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.
