Assessment of aortopulmonary collateral flow and pulmonary vascular growth using a 3.0 T magnetic resonance imaging system in patients who underwent bidirectional Glenn shunting.

OBJECTIVES: To explore the feasibility of evaluating the aortopulmonary collateral flow (APCF) and pulmonary vascular growth of patients who underwent bidirectional Glenn shunting (BGS) using phase-contrast magnetic resonance imaging (PC-MRI) and contrast-enhanced magnetic resonance imaging (CE-MRI).

METHODS: Blood flow measurements of the great vessels of the body were recorded in 22 post-BGS patients using 3.0 T PC-MRI. Right and left pulmonary blood flow (Q(P)), stroke volume (SV) of the ascending aorta (Q(S)), blood flow of descending aorta (Q(d)) and venous return of the superior and inferior venae cavae (Q(V)) per minute were calculated using the Report Card software. APCF was equal to the difference between Q(S) and Q(V). The parameters for pulmonary vascular growth were assessed using CE-MRI. The relationship between pulmonary vascular growth and APCF was evaluated using correlation analysis. A comparative analysis was conducted between the MRI results and the results of five cases who underwent cardiac catheterization and 10 cases who underwent angiography.

RESULTS: Estimated APCF ranged from 0.23 to 1.63 l/(min/m(2)), accounting for 5-44% of Q(S). Morphologic abnormalities such as pulmonary stenosis, dilatation and thrombosis were clearly visualized through CE-MRI. Significant differences in individual pulmonary artery growth were observed. A significant negative correlation was found between APCF and the pulmonary artery index (PAI; r = -0.461, P = 0.031) when the McGoon rate was 2.04 ± 0.59 and the PAI was 253.27 ± 85.86 mm(2)/m(2). Good consistency or relativity was found between cardiac catheterization, angiography and MRI.

CONCLUSIONS: Assessing the APCF and parameters for pulmonary vascular growth in patients who underwent BGS is feasible using 3.0 T PC-MRI integrated with CE-MRI, which may play an important role in clinical and therapeutic decision-making and prognostic evaluation.