Novel three-dimensional electrical impedance tomography for noninvasive detection of lung perfusion.

Background: Non-invasive bedside detection of pulmonary ventilation and perfusion remains a challenge. Electrical impedance tomography (EIT) uses a differential imaging technique to reconstruct images of lung ventilation and perfusion. Conventional methods of perfusion signal acquisition are achieved by breath-holding and hypertonic saline injection, limiting its widespread application. This study aimed to develop a novel EIT methodology for acquiring comprehensive pulmonary ventilation-perfusion images and to validate the reliability of this non-invasive perfusion signal acquisition method across a series of clinical cases.

Methods: A novel three-dimensional EIT (3D-EIT) method for whole-lung ventilation and perfusion imaging was developed. The perfusion signals were acquired by a pulsatility signal-based algorithm. Complete ventilation and perfusion images were reconstructed in healthy subjects and 3D-EIT perfusion imaging was assessed for perfusion defects in patients with pulmonary bullae, undergoing Swan-Ganz catheterization, or with acute pulmonary embolism.

Results: Novel 3D-EIT successfully reconstructed whole-lung ventilation and perfusion images. In patients with pulmonary bullae, EIT perfusion signals at the bullae site were deficient. In patients receiving Swan-Ganz catheterization, the perfusion signals of the corresponding lung segments were reduced when the balloon was wedged and restored when the balloon was released. 3D-EIT also detected significant recovery of perfusion signal at the region of embolism after treatments in patients with pulmonary embolism.

Conclusions: 3D-EIT enables non-invasive monitoring of whole-lung ventilation and perfusion. The fidelity of perfusion images has been demonstrated in several different cases. Novel EIT technology provides many new potential possibilities for the diagnosis and therapeutic evaluation of lung ventilation and perfusion problems.