Possibilities and limitations for high resolution small animal MRI on a clinical whole-body 3T scanner.

Object: To investigate the potential of a clinical 3 T scanner to perform MRI of small rodents.

Materials And Methods: Different dedicated small animal coils and several imaging sequences were evaluated to optimize image quality with respect to SNR, contrast and spatial resolution. As an application, optimal grey-white-matter contrast and resolution were investigated for rats. Furthermore, manganese-enhanced MRI was applied in mice with unilateral crush injury of the optic nerve to investigate coil performance on topographic mapping of the visual projection.

Results: Differences in SNR and CNR up to factor 3 and more were observed between the investigated coils. The best grey-white matter contrast was achieved with a high resolution 3D T (2)-weighted TSE (SPACE) sequence. Delineation of the retino-tectal projection and detection of defined visual pathway damage on the level of the optic nerve could be achieved by using a T (1)-weighted, 3D gradient echo sequence with isotropic resolution of (0.2 mm)(3).

Conclusions: Experimental studies in small rodents requiring high spatial resolution can be performed by using a clinical 3 T scanner with appropriate dedicated coils.