Achieving Optimal Central Venous Catheter Position: Evaluation of Radiographic Landmarks for Accuracy and Inter-observer Reliability in Locating the Cavoatrial Junction

Objective: We sought to compare three popular radiographic landmarks for their accuracy and inter-observer reliability in determination of the cavoatrial junction (CAJ) by analysing the anteroposterior scout and electrocardiogram-gated coronary computed tomographic angiography (CTA) images. Methods: CTA image data of 148 patients were assessed. The position of the CAJ defined by CTA was regarded as the gold standard. The median vertical distance between the CAJ and three radiographic landmarks (two vertebral body units [vertebrae plus discs] below the carina, the superior aspect of the right heart border, and the intersection of the bronchus intermedius with the right heart border) were assessed and compared using the Kruskal–Wallis test. For inter-observer reliability between two radiologists, each with at least 4 years of experience, intra-class correlation (ICC) was analysed. Results: The median vertical distances between the CAJ and two vertebral body units below the carina, the superior aspect of the right heart border, and the intersection of the inferior wall of the bronchus intermedius with the right heart border were 5.1 mm (0-24.6), 10.2 mm (1-45.2) and 9.8 mm (0.8-45.8), respectively. The radiographic landmark of two vertebral body units below the carina provided the closest estimation of the CAJ (p < 0.001). It also demonstrated higher ICC (0.931, 95% confidence interval [CI]=0.905-0.950) than the other two (0.833, 95% CI=0.768-0.880 and 0.860, 95% CI=0.805-0.899, respectively). Conclusion: Among the three popular radiographic landmarks for the CAJ, we found that a point two vertebral body units below the carina provided the most accurate estimate of CAJ location.