Comparison between acoustic radiation force impulse quantification data and perfusion-CT parameters in hepatocellular carcinoma.

Objective: To find out, if ultrasound elastography of hepatocellular carcinoma (HCC) can predict patterns of tumor perfusion in volume perfusion computed tomography (VPCT).

Material And Methods: 25 consecutive patients (mean age, 68.9; range, 51-85 years) with liver cirrhosis suspected of HCC underwent VPCT and acoustic radiation force impulse (ARFI) elastography the same day. Quantitative elasticity values were registered, while blood flow (BF), blood volume (BV) and hepatic perfusion index (HPI) of the HCC lesions were calculated. Additionally, we identified histologic WHO grading, lesion size and localization. The Siemens Acuson S 3000 HELX-System with Virtual Touch™-Software and Siemens Somatom Definition Flash with Syngo software were used.

Results: A total of 43 HCC lesions were assessed. Mean shear wave velocity was 2.6m/s (range, 1.1-4.3m/s). There was no significant linear correlation between the elasticity values and BF (p=0.751), BV (p=0.426) and HPI (p=0.437). However, elasticity values were higher, the larger the tumor was (p=0.008). Shear wave velocity declined with increasing distance of the HCC to the skin surface (p=0.028) and depending on liver segment. In addition, elasticity values were higher in less differentiated HCCs. This trend was not statistically significant (p=0.842).

Conclusion: Tissue elasticity in HCC does not correlate with the degree of tumor vascularization, but calculated values are influenced both by the tumor size and localization inside the liver.