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THE EFFECT OF THE SAMPLE SIZE AND LOCATION ON CONTRAST ULTRASOUND MEASUREMENT OF PERFUSION PARAMETERS

Authors

  • MERJA R. LEINONEN,

    1. Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 57, Helsinki 00014, Finland
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  • MARJA R. RAEKALLIO,

    1. Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 57, Helsinki 00014, Finland
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  • OUTI M. VAINIO,

    1. Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 57, Helsinki 00014, Finland
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  • MIRJA O. RUOHONIEMI,

    1. Department of Equine and Small Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 57, Helsinki 00014, Finland
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  • ROBERT T. O'BRIEN

    1. Department of Clinical Medicine, University of Illinois at Urbana-Champaign, 1008 West Hazelwood Dr, Urbana, Illinois 61802.
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  • Parts of the results in this manuscript have been presented orally and published as an abstract in IVRA 2009 meeting, in Búzios, Brazil.

  • We thank the Orion-Farmos Research Foundation, Helvi Knuuttila Trust and Finnish Veterinary Foundation for financial support.

Address correspondence and reprint requests to Dr. Merja R. Leinonen, at the above address. E-mail: merja.leinonen@helsinki.fi

Abstract

Contrast-enhanced ultrasound can be used to quantify tissue perfusion based on region of interest (ROI) analysis. The effect of the location and size of the ROI on the obtained perfusion parameters has been described in phantom, ex vivo and in vivo studies. We assessed the effects of location and size of the ROI on perfusion parameters in the renal cortex of 10 healthy, anesthetized cats using Definity® contrast-enhanced ultrasound to estimate the importance of the ROI on quantification of tissue perfusion with contrast-enhanced ultrasound. Three separate sets of ROIs were placed in the renal cortex, varying in location, size or depth. There was a significant inverse association between increased depth or increased size of the ROI and peak intensity (P<0.05). There was no statistically significant difference in the peak intensity between the ROIs placed in a row in the near field cortex. There was no significant difference in the ROIs with regard to arrival time, time to peak intensity and wash-in rate. When comparing two different ROIs in a patient with focal lesions, such as suspected neoplasia or infarction, the ROIs should always be placed at same depth and be as similar in size as possible.

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