MRI-based large deformation high dimensional mapping of the hippocampus in rats: Development and validation of the technique

Authors

  • R. Edward Hogan MD,

    Corresponding author
    1. The Department of Neurology, Washington University, St. Louis, Missouri
    • Washington University in St. Louis, Department of Neurology, 660 S. Euclid Avenue, Campus Box 8111, St. Louis, MO 63110
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  • Viviane Bouilleret MD, PhD,

    1. Departments of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
    2. Department of Neurophysiology and Epilepsy, ApHp, CHU Bicetre, Paris, France
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  • Ying Rui Liu,

    1. Departments of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
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  • Lei Wang PhD,

    1. Department of Psychiatry, Northwestern University, Chicago, Illinois
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  • John P. Williams PhD,

    1. The Howard Florey Institute, Parkville, Victoria, Australia
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  • Bianca Jupp PhD,

    1. Departments of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
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  • Damian Myers PhD,

    1. Departments of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
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  • Terence J. O'Brien MD

    1. Departments of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
    2. Department of Surgery, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
    3. The Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia
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Abstract

Purpose

To report the detection of structural and functional biological changes in living animals using small animal in vivo MRI that complements traditional ex vivo histological techniques. We report the development and validation of the application of large deformation high dimensional mapping (HDM-LD) segmentation for the hippocampus in the rat.

Materials and Methods

High resolution volumetric T2 weighted MRI images were acquired at 4.7 Tesla from six male in-breed nonepileptic Wistar rats. Two HDM-LD segmentations of the hippocampus (automated 1 and automated 2) were compared with the manual segmentations of two investigators who independently segmented the hippocampi (manual 1 and manual 2).

Results

The mean overlap for the hippocampi between automated 1 and automated 2 for the right hippocampi was 94.4% (SD 1.0) and for the left hippocampi was 94.3% (SD 2.5), while the mean overlap between automated 1 and manual 1 for the right hippocampi was 91.4% (SD 1.3) and for the left hippocampi was 91.9% (SD 1.4). Mean values for absolute differences for comparisons of all the segmentations were the following: automated 1 versus automated 2, 3.2% (SD 1.0); manual 1 versus manual 2 6.82% (SD 5.22); automated 1 versus manual 1 13.0% (SD 1.8).

Conclusion

HDM-LD can be applied to obtain accurate and reproducible three-dimensional segmentations of the hippocampus from rat MR images. HDM-LD will be a useful tool for investigations of hippocampal structural changes in vivo in rat models of human disease. J. Magn. Reson. Imaging 2009;29:1027–1034. © 2009 Wiley-Liss, Inc.

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