The present invention includes an assembly with a magnet for magnetic resonance having a substrate with an imaging surface and an opening within the substrate adjacent the imaging surface. The present invention enhances the sensitivity and reduces the acquisition time of magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) spectroscopy by cooling the coil using microfluidic channels through which a cryogenic fluid is pumped. Various embodiments have been detailed for clinical imaging or detection in which the integrated coil/microfluidic cryo-cooling system is outside the patient body or in vivo imaging or detection in which the integrated coil/microfluidic cryo-cooling system is inside the patient.