High-resolution medical imaging with full-waveform inversion

Medical imaging is essential for diagnosing and monitoring diseases, but current technologies such as X-rays, CT scans, and MRI present significant limitations. X-rays and CT scans expose patients to ionising radiation, which carries health risks, particularly for those who require repeated scans. MRI, while producing highly detailed images, is costly, non-portable, is contraindicated for patients with ferromagnetic implants and often involves long wait times. These challenges limit the accessibility and practicality of these imaging methods, particularly in time-sensitive cases like stroke, or in regions with limited medical infrastructure. This research aims to further develop and validate a portable, cost-effective ultrasound-based imaging device that integrates full-waveform inversion (FWI) to deliver high-resolution, non-invasive images of the brain, and extend it to image the abdomen and the limbs, offering a safer, faster alternative to current methods. Ultrasound is widely valued in healthcare for its safety, portability, and cost-effectiveness, but traditional methods struggle with producing sufficiently detailed images of complex internal structures, such as the brain, especially in the presence of high-impedance contrasts such as the skull or air-filled tissues. FWI, though well stablished in geophysics, can overcome these limitations by utilising the full waveform of the recorded data and accurate algorithms that model wave propagation through the body, but it has not yet been fully exploited in clinical settings. This project will bridge that gap by refining and integrating FWI algorithms into an advanced and clinically ready ultrasound device that utilises optimally arranged low-frequency transducers to achieve the high resolution and accuracy needed for brain and abdomen imaging. The primary application of this device will be brain imaging. In this phase, the project will consolidate the technology developed to date and validated in a laboratory environment by addressing different challenges that hinder the translation to a clinical setting (e.g. patient movement, lack of low frequencies and flat bandwidth, contact medium). In parallel, the device will be repurposed for abdominal imaging, where current techniques struggle with early detection of conditions like pancreatic cancer by adapting the design of the device, type of sensors and reconstruction algorithms. In its final stage, the system will be optimised for imaging limbs, offering a safer alternative to X-rays and CT scans for musculoskeletal conditions. The impact of this research extends beyond improving image quality. For instance, the ability to detect strokes quickly and accurately with non-ionising ultrasound technology could significantly improve patient outcomes by enabling faster intervention, particularly in emergency settings. Similarly, earlier detection of cancers, such as those affecting the pancreas, could lead to earlier diagnosis, more effective treatments and better survival rates. For musculoskeletal imaging, a portable, affordable, and safer alternative to X-rays would reduce radiation exposure for vulnerable patients and those who require frequent imaging, such as athletes or patients with chronic conditions, reducing their exposure to ionising radiation. Moreover, this technology’s affordability and portability would expand access to advanced imaging capabilities in underserved or remote areas, where traditional imaging infrastructure may be unavailable. In conclusion, this research aims to develop a groundbreaking ultrasound-based system integrating FWI to offer a powerful, portable, and safer alternative to current imaging technologies by addressing the key limitations of MRI, X-rays, and CT scans and delivering faster, more accurate, and more accessible imaging solutions with the potential to significantly improve healthcare outcomes.