Fast imaging and optimization of cryospheric MRI sequences for wet snow

Abstract

We applied several fast-imaging sequences on the water distribution in wet snow using Cryospheric Magnetic Resonance Imager/Imaging (C-MRI). Most of the fast-imaging sequences used for other objects require extremely detailed optimization to obtain high quality images suitable for analysis. However, it is difficult to apply them to C-MRI. Therefore, we have shortened the scanning time by 30 % by applying the standard MRI sequences with compressed sensing that reduces scanning time with Nuclear Magnetic Resonance signal under sampling. Moreover, we have shortened the scanning time by setting an MRI sequence repetition time shorter than the T1 relaxation time of water. As a result, the imaging time to acquire a 3D image of a 51.2 mm cube with a spatial resolution of 0.4 mm was 3.3 min. A guideline for selecting the optimum MRI sequences for measuring the water distribution in wet snow was provided by comparing the imaging time, signal to noise ratio, and area ratio for MRI phantom of each image using various MRI sequences.