MRI measured liver stiffness does not predict focal liver lesions after the Fontan operation

BackgroundFocal liver lesions are common in children and adults after Fontan procedures.ObjectiveTo explore the relationship between liver shear stiffness, using magnetic resonance (MR) elastography, and the presence of focal liver lesions in patients after Fontan procedures (total cavopulmonary anastomosis).Materials and methodsThe retrospective study was approved by the institutional review board and the requirement for informed consent was waived. By searching institutional electronic medical records, we identified all patients with a history of Fontan palliation of congenital heart disease who had undergone same-day liver MR elastography and liver MRI without and with intravenous contrast material between January 2012 and December 2017. Using imaging reports, patients were placed into two groups: 1) no focal liver lesions and 2) one or more focal liver lesions. Patient age, sex, mean liver shear stiffness (kPa) and maximum single anatomical level liver shear stiffness (kPa) were recorded. The Mann-Whitney U test was used to compare age and liver stiffness between groups, while the Fisher exact test was used to assess the impact of gender on liver lesions.ResultsForty-eight patients met study inclusion criteria; 33 (69%) had one or more focal liver lesions. The median age was 20.0years (IQR [interquartile range]: 10.8-29.1years) for patients without liver lesions and 19.9years (IQR: 17.2-27.0years) for patients with liver lesions (P=0.49). Eleven of 21 male patients (52.4%) had liver lesions compared to 22 of 27 female patients (81.5%) (P=0.058). Mean (4.62kPa [IQR: 4.10-5.59kPa] vs. 4.10kPa [IQR: 3.44-4.80kPa]; P=0.02) and maximum (5.53kPa [IQR: 4.64-6.56kPa] vs. 4.50kPa [IQR: 3.82-5.35kPa]; P=0.009) liver stiffness were significantly higher in patients without liver lesions as compared to patients with liver lesions.ConclusionOur study demonstrated a significant negative association between focal liver lesions and increased liver stiffness in patients following Fontan procedures.