Localization of magnetic particles in animal tissues with magnetic resonance imaging

Magnetic resonance imaging techniques were developed and used to locate magnetite particles in biological tissues. To determine the technique's ability to distinguish magnetite, geological magnetite and magnetotactic bacteria suspended in gelatin were imaged initially. Gradient recalled echo acquisition sequences seemed to show magnetite particles better than spin echo sequences. Magnetite was identified in the geological and bacterial samples as high contrast anomalies in a low contrast background. The magnetite anomalies identified in all samples using the spin echo technique increased in size as the echo time was increased. In the bobolink the anomalies were found only in the spiraled turbinates and were commonly seen as left-right pairs. This indicates that the magnetite is not randomly distributed throughout the turbinates, and that it is probably biologically derived. The consistent location and pairing of the anomalies suggest that the magnetite detected in this experiment may be involved in the suspected magnetic orientation capabilities of this bird.