OTU-18\u2005Using X-ray phase contrast imaging to identify oesophageal pathology

Abstract

Introduction Oesophageal cancer is the 5th commonest cause of cancer death in the UK. It accounts for 9,000 new cancer cases every year. Most oesophageal cancers are diagnosed at a late stage. Survival data shows that patients with early disease have a 37.5% 5 year survival compared to 8.4% and 4.9% for those with regional or distant disease.1 Histological diagnosis of oesophageal pathology is an expensive and time consuming process with high inter observer variability. X-ray imaging is inexpensive and has not previously been used for imaging of soft tissue due to poor contrast resolution. X-ray phase contrast imaging (XPCI) uses refraction of x-rays as they pass through a tissue rather than attenuation, which provides much higher soft tissue contrast2. It can also be tuned to have a depth resolution of between 5 μm and 10 mm. This may allow for easy assessment of extent of disease infiltration. Aims We aimed to use XPCI to image four types of oesophageal mucosa, normal squamous, non-dysplastic Barrett’s oesophagus, Barrett’s oesophagus with high-grade dysplasia and oesophageal adenocarcinoma. Methods Following ethical approval, twelve biopsies were obtained both from patients attending for endoscopy at UCLH as well as from the CRUK Cancer Centre Biobank. Biopsies were imaged at the Diamond Synchrotron in beamline i13 using an XPCI technique called free space propagation. We reconstructed the images using MATLAB® software. These CT images were compared to histology from matched biopsies taken at the time of endoscopy or the original histological diagnosis if biobank tissue was used. Results We successfully reconstructed CT images for all four tissue types achieving a resolution of ∼5 microns. We were able to identify normal layered squamous mucosa as well as changes within the structure of the biopsies including glands and goblet cells. The four tissue types appear to have quite different morphology. In addition, the three dimensional tissue structure could be clearly identified, with cancer being the most disorganised. This is the first time that XPCI has been used to image oesophageal biopsies. We have demonstrated the feasibility of the technique and the possibility of obtaining high resolution images which mimic histology with the extra benefit of demonstrating three dimensional structure. References “Oesophageal cancer incidence statistics | Cancer Research UK.” [Online]. Available: https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/oesophageal-cancer/incidence#ref-5. [Accessed: 29-Jan-2019]. Olivo A, Gkoumas S, Endrizzi M, et al. Low-dose phase contrast mammography with conventional x-ray sources. Medical Physics 2013;40(9);90701. doi:10.1118/1.4817480