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Visualization of Uveal Perfusion by Contrast‐Enhanced Harmonic Ultrasonography at a Low Mechanical Index
Author(s) -
Hirokawa Tomihiko,
Nishikage Tomoko,
Moroe Takehiro,
Kajima Makoto,
Hayashi Masakazu,
Naito Takeshi,
Yamane Shinta,
Shiota Hiroshi
Publication year - 2002
Publication title -
journal of ultrasound in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 91
eISSN - 1550-9613
pISSN - 0278-4297
DOI - 10.7863/jum.2002.21.3.299
Subject(s) - mechanical index , medicine , intensity (physics) , perfusion , contrast (vision) , second harmonic imaging microscopy , blood flow , ultrasonography , nuclear medicine , radiology , microbubbles , second harmonic generation , optics , ultrasound , laser , physics
Objectives To evaluate contrast‐enhanced harmonic ultrasonography at a low mechanical index for its usefulness in visualizing uveal perfusion. Methods The study was performed with 9 rabbits, 6 intact and 3 with focal impaired blood flow in the uvea. Ultrasonography was performed by harmonic imaging (transmit, 5 MHz; receive, 10 MHz) with a contrast agent. The agent was administered at a dose of 50 μL/kg. Transmission power was at a mechanical index of 0.2, which is below the US Food and Drug Administration guideline. The images were compared between the impaired and intact eyes. For uveal measurements, video signal intensity–versus–time plots were generated in all cases. The plots were analyzed to obtain the rate of signal intensity increase and peak signal intensity. Results A clear increase of signal intensity was observed after contrast agent administration. The signal intensity of the uvea was lower in the impaired eye than in the intact eye. In the impaired eye, the intensity was lower on the side with impaired flow than on the other side. The differences were significant. Conclusions Our findings suggest that uveal perfusion can be visualized by contrast‐enhanced harmonic ultrasonography in the harmonic imaging mode at a low mechanical index.