Fig. 1From: Magnetism of materials: theory and practice in magnetic resonance imagingThe magnitude image a is the sum of different intravoxel sources of MRI contrast (b), here schematically represented in an onion model. DP = Proton density; T1 = longitudinal relaxation time; T2 = transverse relaxation time; CSh = chemical shift; SM = magnetic susceptibility; MT = magnetization transfer; CEST = chemical exchange saturation transfer; D = diffusion, isotropic (is) and anisotropic (ais); P = PerfusionBack to article page