Value of projectional imaging relative to cross-sectional imaging to assess catheter tip position in the superior vena cava: evaluation of reader variability

OBJECTIVES: The cavo-atrial junction (CAJ) is the most appropriate central venous catheters CVC tip location to reduce complications. Among chest X-ray (CXR) landmarks for tips assessment, only the pericardial reflection lies in the same plane as the vascular structures. We aimed to evaluate the observer variability to determine tip positioning on CXR, using CT as a gold standard. METHODS: We retrospectively analyzed 107 CT scans of patients with port catheters (January-December 2021). The tip to CAJ distance (DCAJ) was measured on both projectional (PJ) and cross-sectional (CS) CT images by 2 × 2 observers (within and between evaluations). Observational statistics included paired t-tests, repeatability coefficients (RC), and intraclass correlation coefficients (ICC), with data visualized using Bland-Altman plots. RESULTS: All ICC were >0.9, indicating excellent reliability. The mean difference between observers comparing CS and PJ was 0.13 ± 0.80 cm (P = .10) with outer 95% confidence limits of 1.92 cm and -2.17 cm and an RC of 1.79 cm. CONCLUSION: CXR provides a reliable method for CVC tip localization, though assessment variability is ±2 cm. ADVANCES IN KNOWLEDGE: CXR assessment of CVC tips shows both intra- and inter-individual variability, due to challenges in identifying the CAJ and catheter tip . While considering the 3 cm anatomical zone around the CAJ acceptable, operators should be aware of the 2 cm variability resulting from CXR assessment. To account for this variability and avoid the risk of positioning the tip beyond 3 cm from the CAJ, operators should reduce the CXR-based acceptable zone to 1 cm around the CAJ, impacting approximately 30% of procedures.