Comparison of retinal and cerebral blood flow between continuous arterial spin labeling MRI and fluorescent microsphere techniques

Authors

  • Yen-Yu I. Shih PhD,

    1. Departments of Neurology, Biomedical Research Imaging Center, and Biomedical Engineering, University of North Carolina, Chapel Hill, North Carolina, USA
    2. Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
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  • Bryan H. De La Garza MS,

    1. Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
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  • Shiliang Huang PhD,

    1. Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
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  • Guang Li MS,

    1. Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
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  • Lin Wang PhD,

    1. Devers Eye Institute, Legacy Clinical Research and Technology Center, Portland, Oregon, USA
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  • Timothy Q. Duong PhD

    Corresponding author
    1. Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
    2. Department of Ophthalmology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
    3. Department of Radiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
    • Address reprint requests to: T.Q.D., Research Imaging Institute, University of Texas Health Science Center at San Antonio, 8403 Floyd Curl Drive, San Antonio, TX 78229. E-mail: duongt@uthscsa.edu, or Y.Y.I.S., Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, 130 Mason Farm Rd, CB#7513, Chapel Hill, NC 27599. E-mail: shihy@unc.edu

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Abstract

Purpose

To compare basal retinal and cerebral blood flow (BF) values using continuous arterial spin labeling (CASL) MRI and fluorescent microspheres.

Materials and Methods

A total of 41 animals were used. BF was measured using an established microsphere technique (a mixture of 2.5 million 8 μm green and 0.5 million 10 μm blue fluorescent microspheres) and CASL MRI blood flow measurement in the rat retina and brain at 7 Tesla (T) and 11.7T, respectively.

Results

Retinal BF by MRI was 1.18 ± 0.57 mL/g/min and choroidal BF was 8.14 ± 1.8 mL/g/min (n = 6). Microsphere retinal BF was 9.12 ± 2.8 μL/min per tissue and choroidal BF was 73.38 ± 44 μL/min per tissue (n = 18), corresponding to a retinal BF value of 1.22 ± 0.36 mL/g/min by means of a wet weight conversion. The wet-weight of the choroid could not be determined. To corroborate our findings, cerebral BF (CBF) by MRI was also analyzed. In the cerebral cortices, CBF was 0.91 ± 0.29 mL/g/min (n = 14) by CASL MRI and 1.09 ± 0.37 mL/g/min (n = 6) by microspheres. There were no significant differences found between MRI and microsphere blood flow in the retina and brain.

Conclusion

BF values in the rat retina and cerebral cortex by MRI are in agreement with those obtained by the microsphere technique. J. Magn. Reson. Imaging 2014;40:609–615. © 2013 Wiley Periodicals, Inc.

Ancillary