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Table 1 Definitions of technical terms in the field of parametric mapping of the heart

From: Clinical recommendations for cardiovascular magnetic resonance mapping of T1, T2, T2* and extracellular volume: A consensus statement by the Society for Cardiovascular Magnetic Resonance (SCMR) endorsed by the European Association for Cardiovascular Imaging (EACVI)

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
\( ECV=\frac{\left(\frac{1}{T1 my{o}_{postGd}}-\frac{1}{T1 my{o}_{native}}\right)}{\left(\frac{1}{T1 bloo{d}_{postGd}}-\frac{1}{T1 bloo{d}_{native}}\right)}\times \left(100- hematocrit\right) \)
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