Evaluation of 2D- Shear Wave Elastography for Characterisation of Focal Liver Lesions

Abstract

Background & Aim: This is a prospective study for evaluation of 2D-shear wave elastography (2D-SWE) for characterisation and differentiation of benign und malignant focal liver lesions (FLLs).Methods: The patients referred to our ultrasound unit were prospectively included. B-mode ultrasound and 2D-SWE (Aixplorer® France) were performed for one FLL in each patient. Liver histology and/or contrast-enhanced imaging were used as a reference method.Results: 140 patients with FLL were included. SWE acquisitions failed in 24% of them. Therefore, 106 patients with FLL could be analysed, 42/106 with benign and 64/106 with malignant FLLs. The median stiffness for benign FLLs was 16.4 (2.1-71.9) kPa: 16.55 kPa for 18 focal nodular hyperplasia (FNH), 16.35 kPa for 18 hemangioma, 9.8 kPa for 3 focal fatty sparings (FFS), 8.9 kPa for 1 adenoma, 20 kPa for one regenerative node and 29 kPa for one cholangiofibroma, and for the malignant FLLs 36 (4.1-142.9) kPa: 44.8 kPa for 16 hepatocellular carcinoma (HCC), 70.7 kPa for 7 cholangiocarcinoma (CCC) and 29.5 kPa for the 41 metastasis (p<0.001). Malignant FLLs were significantly stiffer than benign FLLs (p<0.0001). Cholangiocarcinomas were the stiffest malignant FFLs with significantly higher values as compared to HCCs and metastases (p=0.033 and p=0.0079, respectively). No significant difference in stiffness could be observed between the different benign FLL entities. No significant difference was observed whether 2D-SWE included the whole FLL, the periphery or only the hardest area of the FLL.Conclusions: 2D-SWE provides further characterising information for interpretation of FLLs and may be useful at least in differentiation of CCCs and HCCs.Abbreviations: ALT: alanine aminotransaminase; AST: aspartate aminotransaminase; AUROC: area under the ROC; ARFI: acoustic radiation force impulse; CCC: cholangiocarcinoma; CECT: contrast-enhanced CT; CEMRI: contrast-enhanced MRI; CEUS: contrast-enhanced ultrasound; FFS: focal fatty sparing; FLL: focal liver lesion; FNH: focal nodular hyperplasia; GGT: gamma-glutamyl-transferase; HCC: hepatocellular carcinoma; NASH: nonalcoholic steatohepatitis; pSWE: point shear wave elastography; ROC: receiver-operating-characteristic; ROI: region of interest; 2D-SWE: 2D-shear wave elastography; TE: transient elastography.