Pulsatile Electrical Impedance Tomography for Diagnosis and Monitoring of Acute Pulmonary Embolism

Overview

This multicenter observational diagnostic study aims to evaluate pulsatile electrical impedance tomography (EIT) for the diagnosis and monitoring of acute pulmonary embolism. The study includes a retrospective phase and a prospective phase. EIT-derived ventilation-perfusion matching index, dead-space ventilation index, and intrapulmonary shunt index will be compared with CT pulmonary angiography and relevant clinical indicators. The study is designed to assess whether EIT can provide a noninvasive, bedside, radiation-free method for pulmonary embolism diagnosis, risk stratification, and dynamic treatment monitoring.

Pulmonary embolism is an important type of venous thromboembolism and may be associated with substantial morbidity and mortality. CT pulmonary angiography is commonly used as the reference standard for diagnosis, but it has limitations, including radiation exposure, use of iodinated contrast agents, and limited feasibility for continuous bedside monitoring in some critically ill patients. Electrical impedance tomography is a noninvasive functional imaging technique that can be performed at the bedside and does not involve radiation. This study will evaluate a pulsatile EIT-based approach for assessing pulmonary ventilation and perfusion. The main EIT-derived parameters include the ventilation-perfusion matching index, dead-space ventilation index, and intrapulmonary shunt index. The retrospective phase will collect existing clinical and EIT data from patients with CTPA-confirmed acute pulmonary embolism and healthy controls. These data will be used to compare EIT parameters between groups, evaluate diagnostic performance, and explore optimal cutoff values. The prospective phase will enroll patients newly diagnosed with acute pulmonary embolism and healthy volunteers. EIT examinations will be performed during routine clinical evaluation and follow-up. EIT parameters will be compared with CTPA findings, clinical risk stratification, D-dimer levels, echocardiographic indicators, and clinical outcomes. For patients with pulmonary embolism, serial EIT measurements may be used to evaluate dynamic changes during treatment and follow-up. This is an observational study. Participants will not be assigned to any treatment by the study protocol, and clinical management will be determined by the treating physicians according to routine clinical practice.