Assessing the Influence of Reconstruction Kernel in Plaque Imaging in Computed Tomography

Plaque imaging using computed tomography (CT) is an important diagnostic method for predicting the risk of vascular events. However, the CT value variability of plaques, which depends on the scan parameters, remains a key challenge. The aim of this study was to evaluate the effect of reconstruction properties on the CT value, area, and shape reproducibility of plaques. In general, the types of reconstruction kernels in a CT system are limited, thus impeding the acquisition of the necessary resolution properties (modulation transfer functions: MTFs). We therefore obtained images with eight types (smoothed to edge-enhanced) of resolution property by applying frequency processing to the original CT images. We made phantoms of simulated 6-mm-diameter vessels with plaque and scanned them at different doses. The CT values, areas, and shape reproducibility of plaques were measured from each processed image. Enhanced-type resolution with no edge enhancement (not exceeding 1.0) effectively raised the CT value and shape reproducibility accuracies. However, edge-enhancement type resolution caused errors in the CT value, area and shape reproducibility.