A compact portable MRI system for in-situ imaging and diffusion measurements.

Portable low-field magnetic resonance imaging (MRI) enables non-invasive measurements outside conventional laboratory environments, with emerging applications in plant science and environmental monitoring. In this work, we present a compact and modular MRI system optimized for portability and operation in constrained settings. The system integrates a 0.5T permanent magnet (1.25kg), an openable PCB-based RF coil for intact samples, planar gradient coils, and a miniaturized gradient driver. Its performance is validated through NMR spectroscopy, diffusion measurements, and MRI experiments. Diffusion coefficients of water and agar gel are successfully distinguished, and MRI imaging of structured phantoms achieves an in-plane resolution of 93×93μm2. Preliminary imaging of a living plant sample (Devil's ivy) demonstrates the feasibility of non-invasive measurements on intact plant structures. The presented system provides a compact platform for portable MRI and represents a step toward future in-situ monitoring of water content and transport processes in small plant structures under natural environmental conditions.