Joseph Zambelli PhD, Presenter: Nothing to Disclose

Nicholas Benjamin Bevins MS, Abstract Co-Author: Nothing to Disclose

Zhihua Qi MS, Abstract Co-Author: Nothing to Disclose

Ke Li MS, Abstract Co-Author: Nothing to Disclose

Guang-Hong Chen PhD, Abstract Co-Author: Nothing to Disclose

The purpose of this work is to demonstrate the benefits of x-ray differential phase contrast computed tomography (DPC-CT) imaging as a quantitative, multi-contrast imaging modality in the field of breast imaging.

A grating-based DPC-CT system was constructed at the University of Wisconsin-Madison. Acquisitions of phantoms were reconstructed and used to calibrate the system for quantitative image analysis. The phantoms contained numerous well-characterized plastics with known electron densities and effective atomic numbers. Due to the fundamentally different image formation process in DPC imaging, separate electron density and effective atomic number maps can be simultaneously reconstructed from a single image acquisition, along with the standard attenuation coefficient image. Another contrast mechanism, small-angle scattering (SAS) contrast, can also be used for formation of an additional image that shows the SAS characteristics of an image object. Once calibrated, the system was used to scan diseased human breast tissue samples for quantitative characterization of the diseased and healthy tissue. Resulting image values for healthy tissue and both benign and malignant tumors were compared for each contrast mechanism (absorption, phase contrast, SAS) to determine the benefit of the added contrast mechanisms in diagnosis.

Images of the breast tissue specimens with the multi-contrast imaging technique showed the capability for better differentiation between diseased and healthy tissues than with absorption-based imaging alone. Reconstructions indicated that certain diseased and healthy tissues have different physical properties (electron density or effective atomic number) that result in superior contrast formation in the DPC-CT images compared to traditional absorption CT images, where the attenuation process muddles the physical differences. In addition, the SAS-CT image contained only high-scattering components, e.g., calcifications, while removing the relatively homogenous background.

Grating-based DPC-CT imaging showed greater quantitative and diagnostic capabilities than traditional absorption CT in the case of human breast tissue imaging.

The clinical use of a grating-based DPC-CT imaging system would provide quantitative and multi-contrast imaging that may allow for improved differentiation and unique identification of human tissues.

Zambelli, J, Bevins, N, Qi, Z, Li, K, Chen, G, Multicontrast Cone Beam CT Imaging Using a Talbot-Lau Interferometer.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9008708.html