X-ray elastography: imaging the mechanical properties of tissue using X-rays
The mechanical properties of breast tissue, such as elasticity, have long been known to be an important indicator of tissue health and recent research suggests that peritumoural stiffness is predictive of response to therapy, for specific tumour types. Elastography acquires three-dimensional maps of tissue elasticity and is currently performed using various methods, including optical coherence tomography, magnetic resonance imaging and ultrasonographic imaging. Ultrasonographic elastography is used clinically in both breast and liver cancer imaging. X-ray imaging has, until now, not been used to perform elastography. This project will deliver the first X-ray based images of tissue stiffness.
X-ray imaging has not so far been used to perform elastography because traditional, attenuation based X-ray imaging, lacks the soft tissue contrast required to perform elastography. X-ray phase imaging has superior soft tissue contrast and is being propsed at UCL to perform X-ray phase elastography, for the first time. This project represents an opportunity to perform proof of principle experiments for a novel and topical imaging modality and demonstrate its clinical benefit. Once the clinical benefit is demonstrated, it is proposed to translate this technique for use in X-ray tomosynthesis and an intraoperative margin assessment system currently under development at UCL.
The objectives of the project are: 1) Development a compression stage which allows for CT imaging of ex vivo breast tissue whilst being compressed; 2) Develop medical image computing techniques for extracting the displacement of tissue throughout its volume which is due to mechanical loading; 3) Validate the developed system using phantoms developed as part of another project; and 4) Perform X-ray phase imaging of ex vivo breast tissue. This is a new concept in X-ray phase imaging and is thus an opportunity to break new ground in a project which is a collaboration between a radiology, medical image computing and X-ray phase imaging.
This project relates directly to the clinical research program of cancer imaging. Breast screening and diagnostic imaging continue to be a challenge due to the low contrast offered by conventional X-ray mammography. This technique offers a new contrast mechanism by which breast imaging can be performed. This project fits directly into the image acquisition methodological research theme as it represents a new imaging technique for the existing X-ray phase imaging system. It also fits within computational modelling as the computation of tissue deformation, from CT data sets, in response to an applied load forms an integral part of the project.