Papers Published

1. Rajagopal, JR; Farhadi, F; Negussie, AH; Abadi, E; Sahbaee, P; Saboury, B; Malayeri, AA; Pritchard, WF; Jones, EC; Samei, E, Multivariate snr in spectral computed tomography, Progress in Biomedical Optics and Imaging - Proceedings of SPIE, vol. 11595 (January, 2021) [doi] .
   (last updated on 2025/05/31)

   Abstract:
   In this work, we define a theoretical approach to characterizing the signal-to-noise ratio (SNR) of multi-channeled systems such as spectral computed tomography image series. Spectral image datasets encompass multiple near-simultaneous acquisitions that share information. The conventional definition of SNR is applicable to a single image and thus does not account for the interaction of information between images in a series. We propose an extension of the conventional SNR definition into a multivariate space where each image in the series is treated as a separate information channel thus defining a spectral SNR matrix. We apply this to the specific case of contrast-to-noise ratio (CNR). This matrix is able to account for the conventional CNR of each image in the series as well as a covariance weighted CNR (Cov-CNR), which accounts for the covariance between two images in the series. We evaluate this experimentally with data from an investigational photon-counting CT scanner (Siemens).