Assessment of grating-based X-ray phase-contrast CT for differentiation of invasive ductal carcinoma and ductal carcinoma in situ in an experimental ex vivo set-up
Limited contrast between healthy and tumour tissue is a limiting factor in mammography and CT of the breast. Phase-contrast computed tomography (PC-CT) provides improved soft-tissue contrast compared with absorption-based techniques. In this study, we assessed the technical feasibility of grating-based PC-CT imaging of the breast for characterisation of ductal carcinoma in situ (DCIS).
Grating-based PC-CT was performed on one breast specimen containing an invasive ductal carcinoma and DCIS using monochromatic radiation of 23 keV. Phase-contrast and absorption-based images were compared qualitatively and quantitatively with histopathology in a blinded fashion.
Grating-based PC-CT showed improved differentiation of soft-tissue components. Circular structures of high phase-shift contrast corresponding to the walls of the dilated ductuli of the DCIS were visualised with a contrast-to-noise ratio (CNR) of 9.6 using PC-CT but were not detectable on absorption-based images (CNR = 0.27). The high phase-shift structures of the dilated ductuli were identifiable in the PC-CT volume data set allowing for 3D characterisation of DCIS.
Our results indicate that unlike conventional CT, grating-based PC-CT may allow the differentiation between invasive carcinoma and intraductal carcinoma and healthy breast tissue and provide 3D visualisation of DCIS.
• Phase-contrast computed tomography (CT) yields improved soft-tissue contrast.
• The method can resolve the fine structure of a breast tumour.
• Invasive and intraductal carcinoma can be differentiated.
• Differentiation is possible by visual inspection and quantification.
• The method could improve early breast cancer diagnosis.
KeywordsX-ray phase-contrast imaging Computed tomography Synchrotron radiation Ductal carcinoma in situ (DCIS) Invasive ductal carcinoma
Abbreviations and acronyms
phase-contrast computed tomography
ductal carcinoma in situ
phase-contrast Hounsfield unit
We would like to thank Dr. Thomas Schlossbauer for help with sample acquisition. This work was supported by the Munich Centre for Advanced Photonics Cluster of Excellence (EXC158), Karlsruhe Nano Micro Facility (KNMF) – a Helmholtz Research Infrastructure at Karlsruhe Institute of Technology (KIT) and Siemens Healthcare (Forchheim, Germany). F. Pfeiffer and J. Herzen acknowledge support through the European Research Council (FP7, starting grant #240142). T. Weitkamp is supported by RTRA DIGITEO and Triangle de la Physique (grants 2009-034 T and 2009-79D).
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