Region based 4D tomographic image reconstruction: Application to cardiac x-ray CT

Abstract

X-ray computed tomography (CT) is a powerful tool for noninvasive cardiac imaging. However, radiation dose is a major issue. In this paper, we propose an iterative reconstruction method that reduces the radiation dose without compromising image quality. This is achieved by exploiting prior knowledge in two ways: the reconstructed object is assumed to consist of both stationary and dynamic regions over time and the dynamic region is assumed to have sparse structures after a proper sparsifying space-time transform. Experiments on simulation data and a real µCT cardiac mouse dataset show that, with comparable image quality, the radiation dose can be substantially reduced compared to conventional acquisition/reconstruction protocols.

Improving image quality in fast, time-resolved micro-CT by weighted back projection

“…knowledge on where in the sample the dynamic process may occur. This type of prior knowledge has been used in other algorithms in literature, such as the method presented by Myers et al 23 and region based 4D tomographic reconstruction 24 . In both of these, the static regions are enforced in order not to deviate from their initial value.…”

“…In region based reconstruction 24 , two separate SIRT reconstructions are performed. One, called the static reconstruction, uses the complete projection data, the other uses a small fraction around the time that is being reconstructed and is performed for each time step.…”