  Recent development of photon-counting CT (PCCT) brings great opportunities
for plaque characterization with much-improved spatial resolution and spectral
imaging capability. While existing coronary plaque PCCT imaging results are
based on detectors made of CZT or CdTe materials, deep-silicon photon-counting
detectors have unique performance characteristics and promise distinct imaging
capabilities. In this work, we report a systematic simulation study of a
deep-silicon PCCT scanner with a new clinically-relevant digital plaque phantom
with realistic geometrical parameters and chemical compositions. This work
investigates the effects of spatial resolution, noise, motion artifacts,
radiation dose, and spectral characterization. Our simulation results suggest
that the deep-silicon PCCT design provides adequate spatial resolution for
visualizing a necrotic core and quantitation of key plaque features. Advanced
denoising techniques and aggressive bowtie filter designs can keep image noise
to acceptable levels at this resolution while keeping radiation dose comparable
to that of a conventional CT scan. The ultrahigh resolution of PCCT also means
an elevated sensitivity to motion artifacts. It is found that a tolerance of
less than 0.4 mm residual movement range requires the application of accurate
motion correction methods for best plaque imaging quality with PCCT.
