Extracellular volume quantification using synthetic haematocrit assessed from native and post-contrast longitudinal relaxation T1 times of a blood pool

Table 2 ECV values obtained by different methods of haematocrit estimation

Method of haematocrit estimation	ECV value	ECV bias (95% CI) [%]*	Correlation mean vs. bias (r)	Correlation mean vs. bias (p-value)	r² in haematocrit estimation*
Direct measurement	0.250 ± 0.035	–	–	–	–
Native linear (model 1)	0.250 ± 0.035	0.2 (− 0.7 to 1.1) %	0.03	0.74	0.47
Native reciprocal (model 2)	0.250 ± 0.035	0.2 (− 0.7 to 1.1) %	0.03	0.73	0.47
Combined linear (model 3)	0.250 ± 0.034	0.2 (− 0.7 to 1.0) %	− 0.02	0.78	0.48
Combined reciprocal (model 4)	0.250 ± 0.034	0.2 (− 0.7 to 1.0) %	− 0.03	0.73	0.49
Treibel et al. linear MOLLI**	0.238 ± 0.033	− 4.6% (− 5.5 to − 3.8) %	− 0.13	0.13	0.47
Treibel et al. reciprocal MOLLI**	0.237 ± 0.034	− 5.2 (− 6.0 to − 4.3) %	− 0.03	0.74	0.47
Treibel et al. reciprocal shMOLLI	0.252 ± 0.035	0.8 (− 0.1 to 1.6) %	0.01	0.93	0.47

^*Compared to the direct measurement of haematocrit value
^**Significant bias compared to values obtained by direct measurement of Htc
CI = confidence interval, ECV = extracellular volume, MOLLI = Modified Look-Locker Imaging, Sh-MOLLI = Shortened Modified Look-Locker Imaging

ISSN: 1471-2261