• microscopic magnetic resonance imaging;
  • mouse embryo phenotyping;
  • tissue-specific contrast enhancement;
  • embryonic cellular density;
  • neural stem cell delineation;
  • magnetic resonance histology

Purpose: Worldwide efforts to understand developmental processes demand new high-resolution 3D imaging methods to detect the consequences of gene function in embryo development and diseases. Encouragingly, recent studies have shown that MRI contrast agents can highlight specific tissue structures in ex vivo adult mouse brains. MR imaging of mouse embryos is currently limited by a lack of tissue staining capabilities that would provide the flexibility and specificity offered by histological stains conventionally used for mouse embryo phenotyping.

Methods: The MRI staining properties of two readily available contrast agents, Mn-DPDP and Gd-DTPA, were investigated in mid-gestation mouse embryos.

Results: Brain tissue substructures not normally visible using MRI were detected. Mn-DPDP and Gd-DTPA provided spatially distinct tissue staining patterns. An initial assessment indicated that these agents utilized independent contrast enhancement mechanisms. Mn-DPDP was identified as a potential MRI contrast agent for enhancement of mouse embryonic cellular density and enabled identification of regions containing populations of neural stem and progenitor cells within the intact embryo brain.

Conclusions: Different contrast agents may be used to provide tissue-specific contrast enhancement, suggesting that a host of specialized MRI stains may be available for probing the developing mouse brain and investigating developmental and disease mechanisms. Magn Reson Med 70:1380–1388, 2013. © 2012 Wiley Periodicals, Inc.