Visualization/Quantification of Lung Perfusion without Contrast Agent in Patients with Univentricular Hearts: A Feasibility Study using Arterial Spin Labeling MRI

All articles of this category (opens in new window) Background: Pulmonary perfusion distribution is crucial for Fontan hemodynamics. Conventional MRI visualization requires two peripheral venous accesses, including one from the leg for contrast administration, which is painful and impractical. Arterial spin labeling (ASL) enables contrast-free MRI perfusion imaging by magnetizing water protons in supplying vessels. This study provides proof-of-concept for the feasibility and potential clinical applicability of ASL as a noninvasive alternative in patients with univentricular hearts after TCPC. Methods: Eleven patients aged 21.1 (12.6; 29.8) years [median (Q1; Q3)] were examined 16.4 (8.8; 27.7) years after TCPC with a FAIR True-FISP ASL sequence on a 1.5 T MRI scanner. Slices in coronal, sagittal, and transverse orientations were recorded under free-breathing conditions. The sequence parameters were: TI 1,200 ms, TR/TE 2.2/1.1 ms, FA 70 degrees, voxel size 2.5 × 2.5 × 20 mm 3 , FoV 480 × 480 × 20 mm 3 . Examinations with 24 control/label scans were performed within 3.28 minutes. Quantitative perfusion maps were calculated using a general kinetic model. Results: The visualization of pulmonary perfusion was possible in all patients. ASL images of the lungs showed good quality. Quantitative perfusion mapping of the lung was also possible and showed perfusion values of approximately 300 to 500 mL/minute/100 g measured in parenchymal ROIs (regions of interest). Suitable positioning of the plane of interest was found crucial. Especially with FAIR ASL, it is important that the feeding vessels (IVC/SVC) are not in the recorded plane, as this leads to undesired signal reduction. In cases of heterogeneous anatomy, setting the right position can be challenging. We decided to measure in the sagittal plane (left and right) and one coronal plane. Conclusion: This proof-of-concept study demonstrates that noninvasive ASL MRI can visualize and quantify pulmonary perfusion in patients after TCPC without contrast agents. Further technical development and validation are required before a meaningful comparison with established methods is possible, and the potential value of ASL for patient management in Fontan circulation can be determined. Publication History Article published online: 17 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany