Table 1.

Definitions of technical terms in the field of parametric mapping of the heart

Term	Meaning
T1 [ms]	Time constant representing the recovery of longitudinal magnetization (spin–lattice relaxation)
Native T1	T1 in the absence of an exogenous contrast agent
T2 [ms]	Time constant representing the decay of transverse magnetization (spin-spin relaxation)
T2* [ms]	Time constant representing the decay of transverse magnetization in the presence of local field inhomogeneities
ECV [%]	Extracellular volume fraction, calculated by $ECV=\frac{(\frac{1}{T1my{o}_{postGd}}-\frac{1}{T1my{o}_{native}})}{(\frac{1}{T1bloo{d}_{postGd}}-\frac{1}{T1bloo{d}_{native}})}\times (100-hematocrit)$ where myo = myocardium; blood = intracavitary blood pool; hematocrit = cellular volume fraction of blood [%]
Synthetic ECV [%]	ECV where hematocrit is not measured by laboratory blood sampling but derived from blood T1
Parametric mapping	A process where a secondary image is generated in which each pixel represents a specific magnetic tissue property (T1, T2, or T2*) or a derivative such as ECV) derived from the spatially corresponding voxel of a set of co-registered magnetic resonance source images