Implantable Microcoil for In-vivo Magnetic Resonance Spectroscopy

The Nuclear Magnetic Resonance Spectroscopy (MRS) is the study metabolic processes in different biological and chemical samples as tissues, cell cultures, and protein structures. MRS fulfils an important role through its ability to deduce structural information and to withdraw microscopic data from the intermolecular dynamics. The NMR Approach has expand its capacities to cover furthermost medical and chemical diagnosis applications. However, NMR sensitivity still lags significantly behind most other analytical techniques by a factor of 100-1000, mainly for mass-limited and concentration-limited samples [1]. The observation of metabolic processes using short spin-spin relaxation decay becomes possible via short echo-time localization pulse-sequences. Yet, spectra quantification is obstructed by overlapping metabolite resonances and by low Signal-to-Noise Ratio (SNR) due to the limited size of the observed volume. Hence, the analysis of sample volumes of nanoliter order point toward the improvement of Radio-Frequency (RF) coils having dimensions of several micrometers [2,3]. The sensitivity of an NMR receiver coil is expressed as a ratio of the SNR and the concentration of the measured substance [4]: