Affiliations: Department of Imaging Sciences, University of
Rochester Medical Center, Rochester, NY, USA | Department of Electrical and Computer Engineering,
University of Rochester, Rochester, NY, USA | Department of Physics and Astronomy, University of
Rochester, Rochester, NY, USA
Note: [] Corresponding author: Ruola Ning, Department of Imaging
Sciences, University of Rochester Medical Center, 601 Elmwood Avenue, Box 648,
Rochester, NY 14642, USA. E-mail: Ruola_Ning@urmc.rochester.edu
Abstract: Cone Beam Breast CT is a promising diagnostic modality in breast
imaging. Its isotropic 3D spatial resolution enhances the characterization of
micro-calcifications in breasts that might not be easily distinguishable in
mammography. However, due to dose level considerations, it is beneficial to
further enhance the visualization of calcifications in Cone Beam Breast CT
images that might be masked by noise. In this work, the Papoulis-Gerchberg
method was modified and implemented in Cone Beam Breast CT images to improve
the visualization and detectability of calcifications. First, the PG method was
modified and applied to the projections acquired during the scanning process;
its effects on the reconstructed images were analyzed by measuring the
Modulation Transfer Function and the Noise Power Spectrum. Second, Cone Beam
Breast CT images acquired at different dose levels were pre-processed using
this technique to enhance the visualization of calcification. Finally, a
computer-aided diagnostic algorithm was utilized to evaluate the efficacy of
this method to improve calcification detectability. The results demonstrated
that this technique can effectively improve image quality by improving the
Modulation Transfer Function with a minor increase in noise level.
Consequently, the visualization and detectability of calcifications were
improved in Cone Beam Breast CT images. This technique was also proved to be
useful in reducing the x-ray dose without degrading visualization and
detectability of calcifications.
Keywords: Cone beam breast CT, PG method, breast calcifications, spatial resolution
