T₂-Selective Proton Imaging: Representation of Functional States and Molecular Composition of Tissues

Summary

The parameter-selective proton imaging is a new tool for tissue characterization based on the non-invasive determination of T₂, T₁, the partial volume α, the proton density ρ and the diffusion coefficient D by combining the Carr-Purcell-Meiboom-Gill and the saturation recovery pulse sequences in a single experiment. The decomposition of the multi-exponential transverse magnetization decays leads to the identification of up to four T₂ processes per volume element. The definition of parameter windows in parameter histograms allows the selection of properties of a volume element. The properties can be attributed to proton classes, like extra- and intracellular water, lipids and proteins. Images can be selectively generated by visualizing these proton classes employing the above mentioned NMR parameters as representation variables. The combination of all NMR parameters as selection variables leads to a high degree of differentiation in tissues. Thus, characterization of tissues due to their functional and dysfunctional states and estimates of the tissue heterogeneity can be obtained.