Portable Wideband Microwave Imaging System for Intracranial Hemorrhage Detection Using Improved Back-projection Algorithm with Model of Effective Head Permittivity

Abstract

Intracranial hemorrhage is a medical emergency that requires rapid detection and medication to restrict any brain damage to minimal. Here, an effective wideband microwave head imaging system for on-the-spot detection of intracranial hemorrhage is presented. The operation of the system relies on the dielectric contrast between healthy brain tissues and a hemorrhage that causes a strong microwave scattering. The system uses a compact sensing antenna, which has an ultra-wideband operation with directional radiation, and a portable, compact microwave transceiver for signal transmission and data acquisition. The collected data is processed to create a clear image of the brain using an improved back projection algorithm, which is based on a novel effective head permittivity model. The system is verified in realistic simulation and experimental environments using anatomically and electrically realistic human head phantoms. Quantitative and qualitative comparisons between the images from the proposed and existing algorithms demonstrate significant improvements in detection and localization accuracy. The radiation and thermal safety of the system are examined and verified. Initial human tests are conducted on healthy subjects with different head sizes. The reconstructed images are statistically analyzed and absence of false positive results indicate the efficacy of the proposed system in future preclinical trials.

On-site Rapid Diagnosis of Intracranial Hematoma using Portable Multi-slice Microwave Imaging System

“…This design requirement opposes the compact and light-weight requirement of a portable imaging system. Compactness of the sensing antennas is required to enable using more elements in the array for better imaging quality, as well as reducing the mutual-coupling effects between neighbouring antennas303132333435. All the aforementioned demands of the system make the antenna design process challenging.…”

“…The platform is fabricated using different 3D printed parts. Thus, with a choice of multiple low-cost 3D printing materials, a faster, accurate and unified manufacturing process can be guaranteed compared to the other head imaging prototypes323334. 3D printing also allows the system designers to easily modify the system for any specific environment, e.g.…”

“…Microwave imaging relies on the contrast of the dielectric properties between healthy and unhealthy tissue. Although utilization of microwave frequencies was pioneered for sensing systems for anomaly detection2122232425 and experimental results to identify ICH25 are available in the literature, the imaging of the head interior is demanded to localize ICH position inside the head26272829303132333435363738. Again, for rapid detection of ICH over-simplification of the electromagnetic radiation is noted for the sensing systems, e.g.…”

“…Nonetheless, the reported handful head imaging prototypes rely on sensing antenna’s manual3233 and/or mechanical34 rotational movements, which suffer from vibrations and increase data acquisition instabilities. Nonetheless, as the antenna need to be vertically aligned and concentric to the human head, the data acquisition is highly dependent on the experience and skill of the operator.…”

“…The prototyped system is employed on a 3D anatomically and dielectrically realistic human head phantom. An improved delay-and-sum (DAS) based back-projection algorithm with an effective head permittivity model33 is employed for image reconstruction. A thresholding technique is applied to normalize the reconstructed images by scanning different slices and obtain 3D localization of ICH.…”