Application of electrical resistance tomography for thrombus visualization in blood

Visualization of a thrombus is very important in the development of various artificial organs and extracorporeal circulation devices. This paper presents an application of electrical resistance tomography (ERT) technique for the visualization of a thrombus in blood. Experiments were conducted in static and flowing bovine and swine blood samples. Artificially created thrombi were mixed in the blood samples for visualization. Eight-electrode tomography sensor was used for the measurement. Cross-sectional resistivity distribution was reconstructed using linear back projection algorithm. A thrombus was characterized by increased local resistivity. We successfully reconstructed the time, size and cross-sectional location of a thrombus, and reached a conclusion that the concentration and orientation of the RBCs in a thrombus contributed to the increase in the resistivity. The increment was relatively higher in the static blood than in flowing blood. These findings can be helpful in the development of an instrumentation system for the real-time monitoring of blood to visualize a thrombus. Developers of left ventricular assistance devices, heart-lung machines, hemodialyzer etc., and the end-users (i.e. patients) can greatly benefit from such a system.