Evaluation of liver parenchyma stiffness in patients with liver tumours: optimal strategy for shear wave elastography.

OBJECTIVES: To determine the methodology of non-invasive test for evaluation of liver stiffness (LS) with tumours using two-dimensional (2D) shear wave elastography (SWE). METHODS: One hundred and twenty-seven patients with liver tumours underwent 2D-SWE before surgery to measure liver and spleen stiffness (SS). Two-dimensional SWE values were obtained in the liver at 0-1 cm, 1-2 cm and >2 cm from the tumour edge (PLS-1, PLS-2 and RLS, respectively). The influence of tumour-associated factors was evaluated. The area under the receiver operating characteristic curve (AUC) for each value was analysed to diagnose cirrhosis. RESULTS: PLS-1 was higher than PLS-2, which was even higher than RLS (p < 0.001). The AUCs of PLS-1, PLS-2, RLS and SS for diagnosing cirrhosis were 0.760, 0.833, 0.940 and 0.676, with the specificity of 75.7%, 67.6%, 90.3% and 77.4%, respectively. Tumour sizes, locations or types showed no apparent influence on 2D-SWE values except for RLS, which was higher in patients with primary hepatic carcinomas (p < 0.05). CONCLUSIONS: LS with tumours is best measured at >2 cm away from the tumour edge. SS measurement could be used as an alternative to LS measurement in the event of no available liver for detection. KEY POINTS: • Tumour-associated factors impact background liver stiffness assessment. • Background liver stiffness is best measured at >2 cm from tumour edge. • Spleen stiffness can be an alternative to assess background liver stiffness.

Ultrasound elastography as an imaging biomarker for detection of early tumor response to chemotherapy in a murine breast cancer model: a feasibility study.

OBJECTIVE: This study investigated the feasibility of using strain elastography (SE) and real time shear wave elastography (RT-SWE) to evaluate early tumor response to cytotoxic chemotherapy in a murine xenograft breast cancer tumor model. METHODS: MCF-7 breast cancer-bearing nude mice were treated with either cisplatin 2 mg kg-1 plus paclitaxel 10 mg kg-1 (treatment group) or sterile saline (control group) once daily for 5 days. The tumor elasticity was measured by SE or RT-SWE before and after therapy. Tumor cell density was assessed by hematoxylin and eosin staining, and the ratio of collagen fibers in the tumor was evaluated by Van Gieson staining. The correlation between tumor elasticity, as determined by SE and SWE, as well as the pathological tumor responses were analyzed. RESULTS: Chemotherapy significantly attenuated tumor growth compared to the control treatment (p < 0.05). Chemotherapy also significantly increased tumor stiffness (p < 0.05) and significantly decreased (p < 0.05) tumor cell density compared with the control. Moreover, chemotherapy significantly increased the ratio of collagen fibers (p < 0.05). Tumor stiffness was positively correlated with the ratio of collagen fibers but negatively correlated with tumor cell density. CONCLUSION: The study suggests that ultrasound elastography by SE and SWE is a feasible tool for assessing early responses of breast cancer to chemotherapy in our murine xenograft model. Advances in knowledge: This study showed that the tumor elasticity determined by ultrasound elastography could be a feasible imaging biomarker for assessing very early therapeutic responses to chemotherapy.