Lung Density Measurement in Fontan Patients Using Zero Echo Time Sequences.

Area of Science:

• Cardiology
• Radiology
• Pulmonology

Background:

• Pulmonary complications are a known concern following Fontan palliation.
• Cardiac MRI is standard for Fontan patient follow-up, assessing ventricular function and hemodynamics.
• Lung MRI has not been routinely integrated into Fontan patient imaging follow-up for lung assessment.

Purpose of the Study:

• To investigate the utility of lung MRI, specifically zero echo time (ZTE) sequences, in evaluating pulmonary status in children post-Fontan procedure.
• To assess associations between lung density (measured by lung-to-background ratio, LBR) and various clinical, hemodynamic, and biomarker parameters in Fontan patients.

Main Methods:

• Zero echo time (ZTE) MRI sequences were used to measure lung-to-background ratio (LBR) in 32 children with Fontan palliation.
• Patients were grouped based on LBR (>1.5 vs. <1.5).
• Associations were analyzed between LBR and ventricular function, fibrosis, hemodynamics, biomarkers, spirometry, and prior catheterization results.

Main Results:

• Elevated LBR (>1.5) was significantly associated with increased extracellular volume (ECV) and decreased levels of TIMP-1, sST-2, albumin, and prothrombin time.
• A trend towards decreased GDF-15 was observed in patients with elevated LBR.
• Patients with LBR > 1.5 had a history of higher pre-Fontan/Glenn pulmonary arterial pressure and veno-venous collateral embolization.

Conclusions:

• Monitoring lung density using ZTE MRI sequences shows potential as a diagnostic tool in the follow-up of Fontan procedure patients.
• Lung MRI may help in assessing the long-term outcomes and identifying pulmonary changes not captured by standard cardiac imaging.