Comparison of acoustic radiation force impulse imaging with the convex probe 6C1 and linear probe 9L4

Acoustic radiation force impulse imaging (ARFI) is a noninvasive method to detect liver fibrosis. The aims of the study were to evaluate the difference between 2 different probes, 6 C1 and 9 L4, and to study inter- and intraobserver reproducibility for the probes.

We enrolled 100 patients in this cross-sectional comparative study. All patients underwent liver stiffness measurement with both probes. Intraobserver, interobserver, intralobe, and interlobe agreement was analyzed using the intraclass correlation coefficient.

A significant difference in success rates was observed for both probes between the right and left liver lobes. A success rate of 91% was observed in the right liver lobe compared with 77% in the left liver for the convex probe (P = .007), and 91% vs 68% for the linear probe (P < .001). There was a significant correlation in ARFI-shear wave velocity (ARFI-SWV) between both probes in the right liver lobe (P = .01; r = .508) and in the left liver lobe (P = .05; r = .278); however, there was no significant correlation in ARFI-SWV between the liver lobes for both probes (convex probe r = .19 P = .112; linear probe r = .144 P = .23). Good or excellent inter- and intraobserver was detected for both probes. Poor agreement was found only for the interobserver agreement in the left lobe with the convex probe (ICC = .320).

ARFI can be performed successfully with both probes in both liver lobes. There was no significant correlation in ARFI between the liver lobes for both probes; however, the right liver lobe should be favored. Standardization of the procedure is needed for the comparability of different studies.