Fig. 1

Relationship between signal intensity changes with blood results. a Relationship between the differences in hemoglobin concentration of the blood samples compared to baseline with changes in oxygenation-sensitive signal intensity of arterial and venous blood samples in vitro. Differences in hemoglobin concentration were negatively correlated to changes in signal intensity for venous (r = -0.55, p = 0.002) and arterial blood (r = -0.67, p < 0.0001). b Differences between absolute deoxyhemoglobin concentration (g/L) in venous blood and SI changes (%). There was a moderate relationship between the difference in hemoglobin concentrations and changes in SI (-0.65, p < 0.0001). c Relationship between changes in hemoglobin saturation of venous blood (SvO2) and changes in oxygenation-sensitive signal intensity (%change SI). There was a moderate correlation between venous hemoglobin saturation and signal intensity changes (r = 0.68, p < 0.0001)