Uric acid versus non uric acid urinary calculi: in vivo differentiation using detector-based spectral CT

Description of Research Project: This research project will compare spectral sub-segmental analysis from a non-contrast spectral CT acquisition provides equivalent accuracy in the characterization of urinary calculi compared to the gold standard chemical analysis. Main Research Objectives: To determine the diagnostic performance of spectral sub-segmental analysis from non-contrast spectral CT acquisition for the characterization of urinary calculi compared to gold standard chemical analysis. Expected Outcomes: This study will demonstrate that spectral sub-segmental analysis generated from the detector-based spectral CT dataset can be used in the clinical environment to differentiate between uric acid and non-uric acid urinary calculi. This may reduce the time to treatment for patients with uric acid calculi. Research Design and Method: Data will be collected retrospectively for this study. The study population will be adult patients aged over 18 who have undergone CT Kidney Ureter Bladder (KUB) with clinical suspicion of urolithiasis on a spectral CT scanner in the RBWH Department of Medical Imaging (DMI) since 01 January 2020 to January 2022. Potential participants will be identified from Karisma, the RBWH DMI radiology information system (RIS). The CT image datasets of potential participants will be reviewed by the RBWH research team on Inteleviewer, the RBWH PACS, or on Intellispace Portal, the thin client software routinely used in RBWH DMI for spectral CT analysis, to assess the suitability of potential participants' CT datasets for inclusion in the study. Only members of the RBWH research team will review the CT image data sets using sub-segmental analysis to determine the number, size and composition of renal calculi present on spectral CT reconstruction series. Diagnostic performance of sub-segmental spectral analysis will be compared to pathological chemical analysis and assessed using various statistical methods.