Real-time elastography in differentiating metastatic from nonmetastatic liver nodules

The study was designed to evaluate the role of real-time elastography in differentiating metastatic from nonmetastatic liver nodules, which include various benign lesions, hepatocellular carcinoma (HCC) nodules and lymphoma. Out of 1000 prospective patients who underwent abdominal ultrasound (US) examination, 48 patients had liver nodules. Nodule stiffness was determined by real-time elastography (ES) using color maps and shear wave velocity (SWV) and nodules having marked stiffness or SWV of more than 2.5 m/s were diagnosed as metastatic. The final diagnosis was made on fine needle aspiration cytology. No statistically significant differences were seen on elastomaps in the stiffness of metastatic and nonmetastatic nodules (p = 0.16) while SWV showed statistically significant differences in the strain velocities of benign, metastatic and heptocellular carcinoma nodules p < 0.0001 and < 0.008, respectively. At a cutoff value of SWV 2.5 m/s, the sensitivity, specificity and false positive to detect metastatic nodules by ES were 88%, 83% and 16%, respectively. When the SWV cut off value was set at 2.0 m/s the sensitivity, specificity and false positive were 94%, 70% and 29%, respectively. The study showed that estimation of SWV by ES at a cut off value of 2.5 m/s was a better and a more useful tool in diagnosing both solid and necrotic metastatic liver nodules compared with the color stiffness maps alone.