Evaluation of rat liver with ARFI elastography: In vivo and ex vivo study

Abstract

Objective The aim of this study was to compare in vivo vs ex vivo liver stiffness in rats with acoustic radiation force impulse (ARFI) elastography using the histological findings as the gold standard. Methods Eighteen male Wistar rats aged 16–18 months were divided into a control group (n = 6) and obese group (n = 12). Liver stiffness was measured with shear wave velocity (SWV) using the ARFI technique both in vivo and ex vivo . The degree of fibrosis, steatosis and liver inflammation was evaluated in the histological findings. Pearson’s correlation coefficient was applied to relate the SWV values to the histological parameters. Results The SWV values acquired in the ex vivo study were significantly lower than those obtained in vivo ( P < 0.004). A significantly higher correlation value between the degree of liver fibrosis and the ARFI elastography assessment was observed in the ex vivo study (r = 0.706, P < 0.002), than the in vivo study (r = 0.623, P < 0.05). Conclusion Assessment of liver stiffness using ARFI elastography yielded a significant correlation between SWV and liver fibrosis in both the in vivo and ex vivo experiments. We consider that by minimising the influence of possible sources of artefact we could improve the accuracy of the measurements acquired with ARFI.

Wearable bioadhesive ultrasound shear wave elastography

“…3, C and D). The mean Young’s modulus of normal livers in rats was 4.16 ± 0.55 kPa, which aligns well with the shear modulus measurements of 1.50 ± 0.10 kPa reported in well-established literature ( 22 , 23 ). It is worth noting that the Young’s modulus can generally be assumed as three times the shear modulus according to Eq.…”

Development of a Robotic Shear Wave Elastography System for Noninvasive Staging of Liver Disease in Murine Models

“…( 2 ) Over the past decade, clinical research has demonstrated that SWE and other ultrasound readouts (such as echogenicity, backscatter coefficient, and/or attenuation) are safe and effective at diagnosing a multitude of liver pathologies in humans, including steatosis, ( 3 ) fibrosis/cirrhosis, ( 4 ) and cancer, ( 5 ) and have greatly reduced the reliance on invasive biopsy. ( 6 ) While the integration of SWE, and corollary technologies such as transient elastography, in clinical practice has progressed at a robust pace, there has been a notable lack of adoption of these technologies in preclinical research, despite a growing list of publications demonstrating the feasibility of the approach in rodent models (mice ( 7 , 8 , 9 ) and rats ( 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ) ) and relevancy of these models to human liver stiffness measurements. ( 24 ) Basic science laboratories still mostly rely on histology to assess hepatic injury and response to therapy, ( 25 , 26 , 27 , 28 ) which hampers longitudinal studies because it requires subject endpoints, thus increasing the individuals enrolled and costs.…”