Feasibility of Electric Impedance Tomography in the Assessment of Lung Perfusion and Ventilation in Congenital Pulmonary Vein Stenosis

Pulmonary vein stenosis (PVS) is a complex disease that requires repeated percutaneous interventions. Electrical impedance tomography (EIT) is a functional imaging technique that provides real-time images of pulmonary perfusion and ventilation. We aimed to determine the feasibility of EIT to evaluate ventilation/perfusion in PVS before and after catheter-based interventions. EIT was conducted in patients with PVS using the ACT5 EIT system. Lung regions were segmented from the perfusion images, and time-dependent blood volume curves were computed voxel-wise and by lung region. The distribution of pulmonary blood flow (PBF) was computed from EIT images and compared pre and post intervention. Finally, a blinded interventional cardiologist reviewed the results to evaluate three findings: (1) side and extent of PVS, (2) perfusion, and (3) ventilation. During the study period, twelve patients were included. Of these, seven were female (58.3%) with a median age of 3.5 years. Six patients had history of prematurity, and four had history of previous surgical PVS intervention. Three patients (25%) had an episode of pulmonary hemorrhage during the current intervention. In general, ventilation/perfusion data were successfully obtained in all cases. EIT correctly depicted all 12 cases of PVS correlating with angiography performed on the same day. EIT is a non-invasive, radiation-free technique that estimates lung perfusion/ventilation and percent distribution of PBF. The subject-based evaluation of EIT correlates to the severity and sidedness of the veins involved. This technology has the potential of providing perfusion/ventilation information in-PVS patients without the need of contrast or radiation.