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https://hdl.handle.net/2440/32800
Type: | Conference item |
Title: | Ultrasound induced heating in fetal and neonatal brains is unaffected by altered blood flow |
Author: | Barnett, S. Duggan, P. Horder, M. Vella, G. |
Citation: | Ultrasound in Medicine and Biology, 2000, vol.26, iss.SUPPL. 2, pp.PHO35-PHO35 |
Issue Date: | 2000 |
ISSN: | 0301-5629 |
Conference Name: | Ultrasound in Medicine and Biology |
Abstract: | This paper reports effects of altered cerebral perfusion on ultrasound heating by a simulated pulsed Doppler beam in brains in two perinatal animal models. A 3.5 MHz transducer produced a -6 dB focal beamwidth of 0.26 cm in the brain. The animals were anaesthetized and the ultrasound beam was held stationary during exposure to Ispta intensities 2.8 (fetal guinea-pig in utero) and 1.4 W/cm 2 (neonatal pig). Each exposure was repeated after death. Blood flow in neonatal pigs was increased by induced hypercarbia/hypoxia. The mean maximum temperature increase after 90 s was 4.6 and 1.5 °C for third trimester fetuses and neonatal pigs, respectively. There was no difference between dead (non-perfused) and live (perfused) animals. Increasing blood flow by 200% above normal did not alter brain temperature in neonatal pigs. This supports theory that for clinically relevant narrow beams the extent of ultrasound-induced heating in brain tissue is not significantly altered by vascular perfusion. |
Appears in Collections: | Aurora harvest Obstetrics and Gynaecology publications |
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