Portable Unilateral NMR Measuring System for Burn Depth Assessment

To differentiate burn injuries of various degrees quickly and accurately, a new portable unilateral nuclear magnetic resonance (UNMR) system combined with <inline-formula> <tex-math notation="LaTeX">$T_{2}$ </tex-math></inline-formula> spectral analysis is proposed. The portable UNMR system consists of a handheld unilateral magnet, a radio frequency coil, an integrated field-programmable gate array (FPGA)-based spectrometer, and a simple position device. A rabbit burn model was established, and the transverse relaxation time (<inline-formula> <tex-math notation="LaTeX">$T_{2}$ </tex-math></inline-formula>) spectra of the dermal–fat interface were analyzed. The measured magnetic field is 202.0 mT on the dermal–fat interface of skin (the XOY target plane) with a gradient of 6.42 T/m into the skin (along the <inline-formula> <tex-math notation="LaTeX">$z$ </tex-math></inline-formula>-axis). Experimental results of <inline-formula> <tex-math notation="LaTeX">$T_{2}$ </tex-math></inline-formula> spectrum and hematoxylin–eosin (HE) staining prove that this system has high sensitivity to distinguish deep dermal and full-thickness burns (DFTBs) and superficial partial-thickness burns (SPTBs). Whether the dermal–fat junction layer is damaged or not can be determined with an accuracy of 98%. This new UNMR system and approach has the potential to assess burn depth.