Electrical Impedance Tomography (EIT) is an imaging technology that uses the electrical properties within an anatomic structure derived from measurements made on the structure’s surface. EIT is a non-invasive, non-ionizing, real-time, functional imaging technique with no harmful side effects. EIT is suitable for patients of any age and can be performed continuously at the bedside without sedation. EIT can generate images of lung ventilation, perfusion, and V/Q ratio maps in real time – breath to breath and beat to beat.
GE Research collaborated with academic partners to develop a novel, simultaneous multi-source EIT. We refer to this as SMS-EIT. GE has built prototype SMS-EIT systems with 32 independent channels. Each channel consists of individual current source and voltage measurement circuits for driving and measuring signals operating at 10 kHz operating frequency. Data is acquired at about 20 frames per second with 16-bit accuracy. While other EIT commercial systems exist, they use an inferior approach and multiplex a single (or bipolar) current source about their electrode array. A single source approach affords significantly less capability to detect small inhomogeneities than an SMS-EIT systems in which the number of current sources is equal to the number of skin electrodes. GE’s SMS-EIT design provides higher signal-to-noise ratio and greater sensitivity to image pulmonary perfusion in addition to ventilation.
Non-invasive real-time lung monitoring and assessment is an unmet need for the many high acuity care conditions:
- Differentiate pneumothorax and hemothorax and track its progression for combat casualty care
- Monitor lung function for ventilated patients during aeromedical evacuation
- Enable successful weaning with continuous lung function monitoring following ventilator disconnect
- Monitor lung function and therapy response for premature neonates and pediatric patients
Lung function assessment with EIT presents a radiation free alternative for pediatric and neonate patients. EIT can be implemented as a small, battery-operated and portable device to bring continuous lung assessment to the point of injury for civilian or military trauma applications.
Capabilities utilized for Electrical Impedance Tomography (EIT) for Lung Monitoring project
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