Fig. 1

Schematic illustration of the conventional (a) and inline extracellular volume (ECV) methods (b). a The conventional ECV method derives a partition coefficient (λ_conv) using averaged T1 values from regions-of-interests (ROIs) drawn in the myocardium and blood in native and postcontrast T1 maps. The ECV values are calculated from three different hematocrits (Hct). ECV₀ is derived from an Hct₀ measured on the same day as cardiovascular magnetic resonance (CMR) exam; ECV₁ is derived using Hct₁, which is measured on a different day; ECV_syn is derived using Hct_syn[conv] which is calculated from the native blood T1. b Inline partition coefficient (λ) mapping is automatically generated on a pixelwise basis after image registration of the native and postcontrast T1 maps. The blood mask is automatically generated from native T1 mapping and used to estimate Hct_syn[inline]. Three inline ECV maps were reconstructed with Hct₀, Hct₁, and Hct_syn[inline]. Three ECV values, ECV₀, ECV₁, and ECV_syn, are directly measured from three different inline ECV maps using the same myocardial ROI for T1 mapping