A Study on an Optimal MRI Technique Using a Mouse Coil in a 3.0-T High Magnetic Field: Pulse Sequence and Parameter

Abstract

An animal-dedicated coil was manufactured to improve the image quality in developing a coil for mice used in animal experiments. Various parameters (e.g., the pulse sequence) that can evaluate a range of clinical diseases were changed to determine the optimal high-resolution MRI technique for mouse brains. Balb/C nude mice were used in this experiment. A syringe was used to inject an anesthetic solution (300 ml/kg) into the abdominal cavity of the mice. A 3.0-T system (Magnetom Trio, A Tim System, Germany) was used. The manufactured receive coil was a mouse body coil, which was a receive-only coil with four channels. The coil had a diameter of 40 mm, a length of 100 mm and an overlapped distance between the channels of 4 mm. Image evaluation was conducted based on the signal-to-noise ratio (SNR) and image uniformity for each pulse sequence. The Q value measured in the manufactured coil was 87.7 for mice, which showed a very sharp resonance curve. The measured difference was 39 dB or higher in the case of isolation between the phased array channels. When the SNR and the image uniformity were evaluated, the dual echo steady state with 3 dimensions (DESS 3D, 65.07 +/- 19.42, 77.86 +/- 16.74) showed the highest values, whereas the turbo inversion recovery magnetism with 2 dimensions (TIRM 2D, 05.49 +/- 01.54, 10.19 +/- 03.82) showed the lowest values. In conclusion, the 4-channel phased array coil allowed imaging of a mouse brain with a small diameter. The parameters were changed, depending on the selected pulse sequence, to determine the optimal conditions for images so that high-resolution MR images with a resolution of <= 1 mm could be quickly (within an average of 5 minutes and 30 seconds) acquired.