Towards Microwave Detection of Thromboses

Licentiatavhandling, 2022

Stroke is estimated to be the second most common cause of death with huge
burdens and costs for the patient and society. Since the treatment given to a stroke patient depends on the type of stroke they have, a fast and reliable diagnosis of the stroke type is needed before any treatment can be started. In general, the treatment is more effective the sooner it is started. Thrombectomy is an interventional treatment for patients with an occlusion (thrombosis) in a large artery that is only performed in a limited number of hospitals, thus early detection can support the pre-hospital decision-making process and help decreasing the time to treatment start. The aim of this work is to investigate and develop a method for pre-hospital diagnosis of ischemic stroke by using a microwave diagnosis setup and Contrast-Enhancement Agent (CEA). We propose to exploit the asymmetry created in the brain as a result of partial or full blockage of the arteries due to thromboses. This asymmetry is enhanced with the use of CEA and can be captured by the EM waves transmitted and received by the antennas on the head.
The microwave diagnosis setup consists of several antennas placed on the
body. The multipath interference caused by the waves traveling on the surface
of the body is a factor that limits the detection accuracy of this system. In the present study, a Dielectric Rod Antenna (DRA) is designed to address this challenge with a Self Grounded Bow-Tie Antenna (SGBTA) as the wave exciter. It was shown that DRA can reduce the surface wave power up to 10 dB in comparison with that of SGBTA while increasing its bandwidth by 72%.

Preliminary results obtained from measurements on sheep are promising.