Distortion correction in whole-body imaging of live mice using a 1-Tesla compact magnetic resonance imaging system

Abstract

The aim of this study was to establish a distortion correction applicable to whole-body imaging of live mice. All magnetic resonance imaging (MRI) scans were acquired on a compact 1-T permanent magnet unit for mouse imaging using a T1-weighted, three-dimensional (3D) fast low-angle shot sequence. We assessed geometric distortion in MR images of a small 3D grid phantom and determined 3D image transformations for distortion correction. The developed distortion correction was applied to MR images of the 3D grid phantom acquired on another day, and the correction was validated. A two-dimensional (2D) grid phantom was imaged with a mouse to investigate the applicability of the distortion correction to whole-body mouse imaging. Obvious geometric distortion was observed in the MR images of the 3D grid phantom. The application of the developed 3D phantom-based distortion correction reduced distortion in the images of the 3D grid phantom acquired on another day. Geometric distortion was observed in the MR images of the 2D grid phantom acquired together with the mouse. The 3D phantom-based correction decreased the distortion substantially, regardless of mouse positioning. The developed distortion correction can reduce distortion in whole-body imaging of live mice and may enhance the capabilities of MRI in small animal experiments.