The magnetic resonance imaging (MRI) systems are used for a variety of imaging application. The present invention discloses an improving MRI device and method by amplifying signals received by resonant NMR coils of MRI systems. It utilizes positive feedback from low-noise Field-Effect Transistor to amplify the signal current that can be coupled out to receiving loops positioned externally without loss in sensitivity. Therefore, the NMR coil can be flexibly positioned near internal tissues and used to develop high-resolution images in highly invasive situations. The disclosed device can be developed in kit form as integrated modules that are designed to be added to tuned NMR receiver coils and tailored to deliver specific gains at NMR frequencies.