Orientation Dependent Visualization of Fibers in Digital Breast Tomosynthesis: Advantages of a Circular Source Trajectory

Visualization of fiber-like structures is important in the context of breast imaging. Cooper's ligaments, vessels, ducts, and spiculations from potentially malignant lesions are all examples of fiber-like features that can be present in the breast. In digital breast tomosynthesis, fiber-like signals appear more conspicuous when aligned perpendicular to the direction of X-ray source travel than when they lie parallel. This in-plane anisotropy results from the use of an arc-shaped source trajectory lying in a plane perpendicular to the detector. In this work, we investigate the use of a circular X-ray source trajectory to mitigate the anisotropic visualization of fiber-like signals. A preliminary simulation study is performed to characterize the orientation-dependence of fiber-like signal conspicuity using both arc-shaped and circular source trajectories. The impact of regularization strength employed in reconstruction is also investigated in both geometries. Reconstructions from the arc-shaped trajectory are seen to exhibit orientation-dependent conspicuity and/or depth blur depending on the regularization strength. Using the circular trajectory, these orientation-dependent phenomena are not observed at any regularization strength.