Agatston scores for coronary artery disease derived from true noncontrast and photon-counting CT angiography virtual noncontrast images (PureCalcium algorithm) showed excellent correlation but limi... Background Coronary artery calcium scoring (CACS) for coronary artery disease requires true noncontrast (TNC) CT alongside contrast-enhanced coronary CT angiography (CCTA). Photon-counting CT provi...

Purpose: Qualitative comparison of image quality and diagnostic usability of the recently introduced ZeeFree (ZF) reconstruction algorithm for photon-counting coronary CT angiography (cCTA) with Standard (SD) and TrueStack (TS) reconstruction algorithms. Methods and materials: This retrospective single-center study included 59 patients (mean age 62.5 ± 13.7, 37 males) who were referred for cCTA on a clinical photon-counting CT scanner between July and December 2023. Curved planar reformations were reconstructed for coronary arteries using ZF, SD, and TS algorithms. Three blinded radiologists individually evaluated image quality on a 5-point Likert scale (5 = excellent; median and interquartile range). Differences were evaluated using Friedman’s test with pair-wise post-hoc testing. Readers were advised to assess the image quality to be diagnostic using a dichotomous yes/no question, with results being presented as percentages and significance evaluated by the Pearson Chi-Square test. Interrater reliability for image quality used Gwet’s AC2 coefficient with ordinal weights, and Gwet’s AC1 coefficient for diagnostic usability. Results: ZF showed superior quality (4 (2)) compared to SD (4 (2), p = 0.03) and TS (4 (1), p < 0.001) while a substantial inter-rater agreement was observed for all algorithms (0.70–0.74). Furthermore, ZF obtained the highest diagnostic usability compared to SD (82.5% vs. 77.0%, p < 0.001) and TS (75.5%, p < 0.001) while yielding an almost perfect inter-rater agreement (0.84). Conclusion: Compared to SD and TS, the novel ZF image reconstruction algorithm for photon-counting cCTA provides improved image quality and diagnostic usability, suggesting its primary use for clinical assessment. Key Points: Question How well does the novel ZeeFree algorithm address motion artifacts in photon-counting coronary CT angiography? Findings ZeeFree significantly outperformed Standard and TrueStack reconstruction algorithms for image quality and diagnostic usability. Clinical relevance Enhanced image quality with ZeeFree could improve the diagnosis of coronary artery disease.

Objectives: Evaluating esophageal cancer (EC) response to neoadjuvant radiochemotherapy (NARC) has been challenging, but photon-counting CT (PCCT) provides multiparametric data, including iodine concentration (IC), which can be utilized for evaluation. This study explored the relationship between IC and histopathological features of EC, assessing its role in predicting NARC responses. Materials and methods: Of 105 patients with EC, 85 (67 men; mean age 66.0 ± 11.0 years) met the inclusion criteria and underwent PCCT scans during the portal venous phase. Normalized iodine concentration (NIC) was calculated, and tumor characteristics, including stage, grade, and lymphovascular invasion, were analyzed. Statistical analyses included Mann–Whitney U tests, sensitivity, specificity, and area under the curve (AUC) calculations. Interobserver reliability of NIC measurements was assessed. Results: Interobserver reliability for NIC was excellent (ICC = 0.99 for all tumors, p < 0.01). In adenocarcinoma, NIC was lower in good therapy responders (Becker 1a/1b: 0.40 ± 0.13) than poor responders (Becker 2/3: 0.51 ± 0.12, p = 0.01). An NIC cutoff ≤ 0.41 predicted good regression (OR = 4.77, p = 0.03; AUC = 0.704, sensitivity = 72.2%, specificity 64.7%). Poor response prediction showed moderate accuracy (AUC = 0.662). Conclusion: NIC values show excellent interobserver agreement and can predict treatment response to NARC in EC, particularly for adenocarcinomas, where lower NIC values are linked to better outcomes. While NIC provides good predictive value, further studies with larger sample sizes are needed to confirm these findings and explore additional factors influencing outcomes. Key Points: Question Does photon-counting CT-derived iodine concentration correlate with key histopathological features in esophageal cancer and predict response to neoadjuvant radiochemotherapy? Findings Photon-counting CT–derived normalized iodine concentration in esophageal adenocarcinoma moderately predicted treatment response, despite no correlation with tumor grade or Ki-67 . Clinical relevance Normalized iodine concentration values from photon-counting CT, obtained during routine staging exams, offer an objective method for predicting treatment response in esophageal adenocarcinoma, enabling more precise therapy planning and personalized patient management . Graphical

Septic arthritis is common in older adults and can be related to joint surgery or hematogenous distribution. To date, the risk factors affecting survival are unknown. This study aimed to evaluate the effects of existing implants, positive synovial microbiological culture results, and the American Society of Anesthesiology Physical Status (ASA) classification on the short- and mid-term survival of older patients with primary septic gonarthritis. This retrospective study included 133 older adults >60 years who underwent surgery for primary septic gonarthritis. Data were collected from medical records and public obituaries. Kaplan–Meier survival curves were used to estimate the probability of survival, as well as log-rank tests to measure and compare survival rates over one- and five-year periods. The mean age was 74.9 years (SD ± 9.2), and the 5-year follow-up rate was 74.3% (the mean follow-up was 3000.5 days; SD ± 1771.6). Mean survival was significantly different in patients with implants and without implants (p = 0.015), and between ASA II, ASA III, and ASA IV (p < 0.001). There was no significant difference in the survival of patients with or without a positive synovial microbiological culture (p = 0.08). Older adults with septic monoarthritis and pre-existing medical implants showed impaired survival. The ASA classification prior to surgery for primary septic monoarthritis can be helpful in identifying patients with poorer mid-term outcomes.