High Resolution Magic Angle Spinning (HRMAS) Proton MRS of Surgical Specimens

Abstract

Over the last two decades, a large body of ex vivo work and some in vivo work has demonstrated the utility of proton magnetic resonance spectroscopy (1H MRS) in detecting and monitoring cellular chemical alterations associated with the development and progression of human malignant diseases [1-3]. Reports of conventional ex vivo 1H MRS studies of human tissues, i.e. analysis of intact tissues with liquid-state MRS probes, have demonstrated that diagnosis, and for some organs, prognosis of malignant disease using metabolite ratios measured from spectra may reach 95% for both sensitivity and specificity. The accuracy can further be improved using an objective pattern recognition technique, statistical classification strategy (SCS) [2]. While tissue conventional MRS is fast and has shown the ability to diagnose accurately various human malignancies, it is limited by poor spectral resolution caused by the magnetic susceptibility effects of heterogeneous structures of the sample, and therefore detailed identification of individual metabolites is difficult. Metabolite profiling involving the measurement and quantification of tissue metabolites [4] is of increasing interest in the era of genomics and proteomics due to the direct involvement of tissue metabolites in tumor development and progression. High-resolution magic angle spinning (HRMAS) was developed to improve the spectral resolution of MR spectra of intact tissue by the reduction of susceptibility induced broadening such that individual metabolites may be identified and correlated with disease states.