Comparing Acoustic Radiation Force Impulse Imaging to transient elastography to assess liver stiffness in healthy volunteers with and without valsalva manoeuvre

Abstract

Purpose: Acoustic Radiation Force Impulse Imaging (ARFI) is a new ultrasound elastography technology (Siemens ACUSON S2000 Virtual Touch TM Tissue Quantification), which is integrated in conventional ultrasound equipment. In preliminary studies, ARFI sheer wave speed (SWS) in liver tissue correlated well with transient elastography (TE) values and liver fibrosis stages.Materials and methods: Sixty-eight healthy male and female volunteers were measured with ARFI with two ultrasound tranducers, three measuring positions and during valsalva manoeuvre. A TE (FibroScan TM , Echosens, France) was performed in 60 volunteers.Results: Volunteers had a mean age of 28 years and a mean BMI of 22.3. There was no significant difference of ARFI SWS between the 4C1 and 4V1 ultrasound probes in either intercostal or abdominal approach to liver segment 8 but a higher variance of ARFI SWS with the 4V1/abdominal compared to the intercostal approach (p = 0.0368). The 4C1/intercostal approach had the highest success rates (97.2%), comparable to those of TE (97.18%). Left liver lobe measurements obtained both significantly higher ARFI SWS and value variance (p = 0.0016 and p = 0.0198) compared to 4C1/intercostal approach. Mean ARFI SWS was 1.19 m/s (range 0.77-1.63). Mean TE was 5.39 kPa (range 3.3-9.0 kPa). Valsalva manoeuvre did not significantly alter ARFI SWS and variance. Skin-liver distance significantly influenced ARFI SWS (p < 0.05), while age and gender did not.Conclusion: These results might constitute a first impression of the chances of ARFI SWS to assess liver stiffness, especially in patients with liver diseases due to increased venous pressure.

Physiologic Reduction of Hepatic Venous Blood Flow by the Valsalva Maneuver Decreases Liver Stiffness

“…Other elastographic methods were not sensitive to the Valsalva maneuver or yielded mixed results. [18][19][20] The contrast to previously published research exploring the impact of the Valsalva maneuver on liver stiffness is most likely related to a number of factors, including the following: (1) time-harmonic elastographic mechanical excitation exploits a lower dynamic range than acoustic radiation force impulse or other transient-based elastographic measurements; (2) time-harmonic elastography can examine major portions of the right liver along profiles of approximately 14 cm in length; and (3) We used short breath-holding intervals of no longer than 3 seconds for our measurements. Breathing-related flow alterations have been demonstrated to be important for other elastographic methods as well.…”

Shear wave elastography of the liver – review on normal values

“…However, others showed that respiratory status (e. g., apnea versus free-breathing) did not influence LSM [8]. Valsalva maneuver did not influence the values [53]. It has been suggested that a breath hold for a few seconds during quiet breathing may lead to optimal results [11,12].…”

Standard value of ultrasound elastography using acoustic radiation force impulse imaging (ARFI) in healthy liver tissue of children and adolescents.

“…By measuring during continuous speech or while crying, movement of the diaphragm is minimized. In literature a thereby produced Valsalva has no significant effect on the ARFI elastrography value [23].…”