Effect of contrast agent on the incidence and magnitude of ultrasound-induced lung hemorrhage in rats.
OBJECTIVE
To test the hypothesis that inertial cavitation in the vasculature of the lung is not the physical mechanism responsible for ultrasound-induced lung hemorrhage.


METHODS
A factorial design was used to study the effects of two types of injected agents (IA; 0.25 ml per rat of saline or Optison given intravenously) and two levels of pulsed ultrasound exposure (UE; in situ peak rarefactional pressures of 2.74 and 5.86 MPa; respective mechanical indices of 1.02 and 2.14) on the incidence and size of lung lesions. Ten 10-to-11-week-old Sprague-Dawley rats were exposed to pulsed ultrasound at each of the four combinations of IA and UE at a center frequency of 3.1 MHz, exposure duration of 10 s, pulse repetition frequency of 1,000 Hz and pulse duration of 1.2 micros. In addition, nine rats served as shams in which no lung hemorrhage occurred.


RESULTS
Rats administered contrast agent prior to exposure did not have an increase in lesion occurrence or size compared to rats that received saline with no contrast agent.


CONCLUSIONS
These results provide further evidence that the mechanism for production of lung hemorrhage is not inertial cavitation.
O'Brien
William D
WD
Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering, University of Illinois, Urbana, 61801, USA. wdo@uiuc.edu
Simpson
Douglas G
DG
Frizzell
Leon A
LA
Zachary
James F
JF
D000418:Albumins / Q000008:administration & dosage / Q000009:adverse effects; D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage* / Q000009:adverse effects*; D004195:Disease Models, Animal; D005260:Female; D005466:Fluorocarbons / Q000008:administration & dosage / Q000009:adverse effects; D006470:Hemorrhage / Q000453:epidemiology* / Q000209:etiology*; D015994:Incidence; D008171:Lung Diseases / Q000453:epidemiology* / Q000209:etiology*; D008955:Models, Cardiovascular; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride / Q000008:administration & dosage / Q000009:adverse effects; D018084:Ultrasonography, Interventional / Q000009:adverse effects*
D000418:Albumins; D003287:Contrast Media; C099458:FS 069; D005466:Fluorocarbons; D012965:Sodium Chloride