Assessing liver tumor stiffness by transient elastography

Transient elastography is a novel noninvasive method to assess liver fibrosis by measuring liver stiffness. This study is a first step toward the provision of a noninvasive measurement of hepatic tumor stiffness by transient elastography.

Patients with liver tumor larger than 5 cm in diameter and located near the liver surface were enrolled between June 2004 and February 2005. Histology of each tumor was evaluated on ultrasound-guided liver biopsy specimens. Transient elastography (Fibroscan, Echosens, Paris) was used to measure tumor stiffness. Tumor stiffness was measured as follows. First, by using B-mode ultrasound, we searched for the optimal right intercostal position for tumor stiffness measurement while keeping the ultrasound probe and body surface at right angles. Then the vibrator for transient elastography was applied at the same position and angle, and stiffness was measured according to the manufacturer's instruction.

Tumor stiffness was measured in 40 patients, 17 with hepatocellular carcinoma (HCC), six with cholangiocellular carcinoma (CCC), 16 with metastatic tumors (mostly adenocarcinoma), and one with malignant lymphoma. The median value was 55 kPa in HCC, 75 kPa in CCC, 66.5 kPa in metastatic tumor, and 16.9 kPa in malignant lymphoma. The stiffness value of CCC was significantly higher than that of HCC and metastatic tumors (P = .049).

We showed that stiffness of liver tumors could be measured with transient elastography. Improvements in the device, such as smaller and variable region of interest of measurement and real-time B-mode display, may ensure wider clinical application.