Clinical Relevance of Mr Spectroscopy in the Spinal Cord

SUMMARY: MR spectroscopy allows insight into the chemical composition of human tissue noninvasively. Thereby it can help to better characterize pathologic processes affecting the spinal cord andmay provide important clinicalmarkers for differential diagnosis. However, due to technical challenges, it has been rarely applied to the spinal cord. The aim of this review was to summarize the technical development and clinical studies usingMR spectroscopy in the spinal cord.Main challenges of applyingMR spectroscopy in the spinal cord are discussed, and a description of a state-of-the-art scan protocol is given. In conclusion,MR spectroscopy is a promising tool for research and diagnosis of the spinal cord because it can provide additional information complementary to other noninvasive imaging methods. However, the application ofMR spectroscopy in the spinal cord is not straightforward, and great care is required to attain optimal spectral quality. ABBREVIATIONS: CRLB Cramér-Rao lower bounds; ECG electrocardiogram; FWHM full width at half maximum; IVS inner-volume suppression; OVS outer-volume suppression MR spectroscopy enables the determination of metabolite concentrations in a predefined region of interest in the human body, both noninvasively and in vivo. In contrast to other MR imaging techniques, such as diffusion-weighted imaging, blood oxygen level– dependent contrast imaging, or structural MR imaging methods, MR spectroscopy provides information about the chemical microenvironment from atomic nuclei in a variety of functional groups. This allows detection of changes in the concentration of various metabolites for investigating healthy tissue and pathologic processes and exerciseor drug-induced changes. In vivo, MR spectroscopy is mainly based on proton (H), carbon (C), or phosphorous (P) nuclei. Due to the 100% natural abundance and the highest gyromagnetic ratio of protons among the above-mentioned nuclei, H-MR is the most sensitive in vivo spectroscopy method. In addition, H-MR spectroscopy requires the same hardware as clinical MR imaging and can thus be integrated into clinical scan protocols in an efficient way. Hence H-MR spectroscopy became a promising tool for basic physiologic studies and clinical