ATLA::Alternatives to Laboratory Animals

Volume 26, Number 3

Magnetic resonance imaging of the common marmoset head.

ATLA 26, 343-356, May/June 1998

Vee-Meng Lee1, Newman G. Burdett1, T. Adrian Carpenter1, Nicholas J. Herrod1, Michael F. James2, and Laurance D. Hall1

1The Herchel Smith Laboratory for Medicinal Chemistry, University of Cambridge, School of Clinical Medicine, Robinson Way, Cambridge CB2 2PZ, UK; 2SmithKline Beecham Pharmaceuticals, New Frontiers Science Park (North), Third Avenue, Harlow, Essex CM19 5AW, UK

SUMMARY

This study evaluated the changes in the intrinsic magnetic resonance (MR) relaxation parameter values (T1, T2, proton density, magnetization transfer and apparent diffusion coefficient) of the marmoset head, imaged before and after death. Knowing the absolute values of the MR parameters makes it possible to choose an imaging protocol for optimal structural differentiation. The changes between the ante-mortem and post-mortem MR parameters provide an insight into the changing biophysical microenvironment of the post-mortem brain, and allow some of the changes that occur in pathological conditions to be predicted. Diffusion-weighted MR imaging (MRI) was used to map quantitative apparent diffusion coefficient values, and to investigate diffusional anisotropy along the fibre tracts in pre-mortem and post-mortem brain tissue. A three-dimensional data set of the entire marmoset brain demonstrates the ability of three-dimensional MRI to differentiate internal brain structures. MRI is a non-invasive technique which, in principle, permits the same animal to be re-imaged serially and has the potential to probe in vivo brain structural and biophysical changes over an extended period of time. Serial imaging, where each animal acts as its own control, reduces the number of animals required to detect a significant change by minimising the effects of inter-subject variance. MRI therefore provides important scientific and ethical benefits.

Keywords: magnetic resonance imaging (MRI), brain, marmoset, quantitative relaxation maps, diffusion-weighted imaging