Peripheral vs. central parametric mapping of the liver in single ventricle patients: Measurement location matters

Fontan circulation often results in Fontan-associated liver disease, typically challenging to detect early. MRI liver parametric mapping shows potential for tissue characterization, but institution-specific reference values hinder comparability. This study investigates whether the peripheral-to-central mapping ratio can serve as a surrogate for absolute mapping values.

The retrospective single tertiary center cohort study included 68 pediatric patients with single ventricle anomalies and 25 healthy controls. Parametric mapping values were measured in three liver regions, comparing central region and peripheral areas of both liver lobes.

There was a strong positive correlation between the T1 ratio and T1 mean (r = 0.68, p < 0.001), and a moderate positive correlation between the T2 ratio and T2 mean (r = 0.46, p < 0.001). T1 and T2 mapping ratios exhibited the highest values in post-total cavopulmonary connection (TCPC) patients (p < 0.05). Post-TCPC patients had significantly higher T1 and T2 mapping, and ECV values in the right lobe compared to the left lobe (p < 0.05). T1 mean showed significant weak associations with duration of post-TCPC follow-up (r = 0.3, p = 0.029), ejection fraction (r = -0.36, p = 0.006), oxygen saturation (r = -0.31, p = 0.022), and univentricular end-diastolic volume (r = 0.27, p = 0.043), and severe lymphatic collaterals were linked to higher T1 mean values (p = 0.024) in post-TCPC patients. Absolute T1 values were significantly higher in cirrhosis across all tested regions (p < 0.05). The T1 ratio was significantly associated with the duration of post-TCPC follow-up (r = 0.27, p = 0.041).

Measurement location influences liver parametric mapping values. The T1 ratio shows the most promise among the peripheral-to-central ratios, though its associations with hemodynamics are weaker than those of absolute values.