Microwave technology for detecting traumatic chest injuries in a porcine model

The electromagnetic properties of microwaves are altered by the dielectric properties of biological tissues, allowing microwave technology (MWT) to be used to detect free air and blood in the body. This animal study investigated whether MWT could be used as a point-of-care approach for the diagnosis of pneumothorax (PTX), haemothorax (HTX) and haemopneumothorax (HPTX). A porcine model of PTX (50–1500 mL), HTX (50–750 mL) and HPTX (750 mL blood and 50–1500 mL air) was established, by injecting air and blood in the pleural cavity. A MWT device with eight antennas was positioned around the chest, and all antenna pair combinations were measured and analysed for attenuation of magnitude. All stages of HPTX and larger stages of PTX and HTX induced significant changes in the microwave signals. Attenuation of the signal increased with increasing air and/or blood volume. Although trauma-induced changes were significant compared to the baseline, the interindividual variance exceeded the trauma-related changes. Microwave signals were significantly altered by free air and blood and the attenuation correlated with the size of the PTX, HTX and HPTX. MWT can potentially complement point-of-care diagnostics for severe thoracic injuries. However, further improvement is necessary before clinical testing.