Quantitative information derived from MRS lineshapes affected by material heterogeneity - principles, applications and future potential in biomedicine

Quantifying tissue heterogeneity is a major challenge in biomedical MRS and MRI. We present here a review of several closely related recent methods for deriving, from MRS lineshapes via histograms, quantitative statistical information on heterogeneity, and point out current and future biomedical applications. At present, heterogeneity in parameters such as ion concentrations (H⁺, Ca²⁺, Mg²⁺, Na⁺) are being targeted, but also thermal heterogeneity (relevant to hyperthermia) has been proven to be accessible to this type of spectral analysis. Future in-vivo studies are expected to benefit from the wider window into the regulation of physicochemical parameters, enabled by the new underlying paradigm.