Measurement of shear wave velocity in acoustic radiation force impulse imaging before and after contrast administration

Aims: Acoustic Radiation Force Impulse imaging (ARFI) and contrast enhanced ultrasound (CEUS) are often performed for the same patient, especially for patients with focal liver lesions (FLL). CEUS could affect velocity measurements in vivo and in vitro. Whether microbubbles affect the measurement of shear wave velocity (SWV) is still unknown.

Purpose: To assess the inter-observer reproducibility of ARFI between two skilled physicians and to evaluate if CEUS affect the measurement of SWV in ARFI.

Patients and methods: 53 patients (29 males, 24 females, age: 59 ± 15 [22 – 84] years) who underwent CEUS examination were included. ARFI was performed on liver segment V by physicians A and B before CEUS, and by physicians A within 4 – 6 minutes and 7 – 10 minutes after contrast injection. In a subgroup of 31 patients (15 males, 16 females, age: 57 ± 18 [22 – 84]), ARFI was also performed on FLL by physician A before CEUS, and within 4 – 6 minutes and 7 – 10 minutes after contrast injection, respectively.

Results: The SWV values obtained by physician A and B before CEUS yielded an intra-class correlation coefficient value of 0.913 (95%CI, 0.849 – 0.950). No significant differences were shown between the SWV values before CEUS and within 4 – 6 minutes and 7 – 10 minutes after contrast injection (all P > 0.05) in both liver parenchyma and FLL.

Conclusion: ARFI showed excellent inter-observer reproducibility between two skilled physicians. UCA did not affect the measurement of SWV after contrast injection in both liver parenchyma and FLL.