In Vivo 1H Nuclear Magnetic Resonance Spectroscopy and Relaxometry Maps of the Human Female Pelvis

An essential organ of the female reproductive system, the uterus, is histologically divided into three layers: the perimetrium, myometrium, and endometrium. In vivo nuclear magnetic resonance (NMR) imaging and spectroscopy are modern methods that become important tools used by radiologists to increase the degree in confidence in their diagnosis, to provide noninvasive metabolic information, and to establish a standardized characterization of the nonpathological tissue. We developed a complex protocol based on in vivo magnetic resonance spectroscopy and imaging correlated with data analysis for the assessment of specific parameters, such as metabolite content, H-1 spin-density, effective transverse relaxation time, and effective longitudinal relaxation time parameter maps, characteristic of normal endometrium in a group of 11 healthy volunteer women. This study involved: (i) a series of data analysis steps performed by a dedicated software and primary NMR signal processing (water and metabolite signal separation, phase and baseline correction, apodization) and (ii) advanced analysis based on dedicated programs. We observed and investigated three states of water: free water, loosely and strongly bound water characterized by different transverse relaxation times. The four most common metabolites reported in previous studies of malignant uterus were identified for normal endometrium. Qualitative transverse and longitudinal relaxation time parameter maps were obtained. The distributions of transverse relaxation times for various uterine areas were demonstrated by statistical analysis. The good signal-to-noise ratio allows the identification of other metabolites such as N-acetyl aspartate and M1 and M2 macromolecular resonances. A relatively high choline and lipid content and low creatine and lactate content were calculated for the group of healthy women.