Determination and prospective validation of cut-off values for the diagnosis of liver cirrhosis for point shear-wave elastography/acoustic radiation force impulse imaging using the ACUSON Sequoia ultrasound system

Abstract

Objectives Point shear-wave elastography (pSWE) alias acoustic radiation force impulse (ARFI) imaging is a well-established ultrasound-based technique for the non-invasive assessment of liver tissue stiffness. As cut-off values for liver cirrhosis cannot be transferred from one ultrasound system to another, this study aimed at determining cut-off values for the newly developed Siemens ACUSON Sequoia ultrasound system. Methods In a pilot study phase, two independent examiners conducted 10 pSWE measurements in an elasticity phantom and 32 healthy individuals for the determination of inter-examiner agreement. Afterwards, 22 cirrhotic patients and 57 patients with chronic liver disease undergoing liver biopsy underwent pSWE. Patient characteristics and stiffness values were compared for individuals with and without liver cirrhosis. Diagnostic accuracies of cut-off values for the diagnosis of liver cirrhosis were calculated using areas under the receiver operating characteristics analysis and Youden’s index. In a subsequent validation study phase, these cut-off values were validated prospectively in 107 cirrhotic and 68 non-cirrhotic patients. Results Inter-examiner agreement was excellent for measurements in the elasticity phantom (intra-class correlation coefficient [ICC] = 0.998; P < 0.001), and good for measurements in patients (ICC = 0.844; P < 0.001). The best cut-off value for the diagnosis of liver cirrhosis was 1.405 m/s with an AUC of 0.872, a sensitivity of 88.2% and a specificity of 88.2% (P < 0.001). Conclusion ARFI elastography using the Siemens ACUSON Sequoia showed a good inter-examiner agreement. The optimal cut-off value was lower than the cut-off values described for former generations of ultrasound devices. These preliminary results should be confirmed in larger patient collectives with histology as the reference standard.