Fig. 4From: Ultrasound localization of central vein catheter tip by contrast-enhanced transthoracic ultrasonography: a comparison study with trans-esophageal echocardiographyROC curves for subcostal bicaval transthoracic echocardiography (subcostal Bicaval TTE), apical four-chamber transthoracic echocardiography (apical four-chamber TTE) and chest-x-ray (CXR), with transesophageal echocardiography assumed as reference. AUC area under curve (95% confidence interval)Back to article page