Value Of Ultrasonic Elastography In Differentiating Benign And Malignant Liver Tumors

Background & ObjectiveHepatocellular carcinoma is the fifth most common cancer in the world and the third most common cause of cancer mortality. Ultrasonography is one of the most commonly used method in diagnosis and differential diagnosis of various liver disease, because of its convenience, noninvasive, inexpensive and high repeatability. The conventional ultrasonic inspection makes the differential diagnosis of benign and malignant tumors mainly through the observation of the lesion size, edge, morphology, echogenicity of liver disease, which has some limitations. Ultrasonic Elastography (UE) is a novel technique established by Ophir in 1991. UE makes the diagnosis of benign and malignant tumors through the detection of the lesion rigidity. UE is appropriate for and maturely used in the superficial tumors, especially in the differential diagnosis of benign from malignant breast lesions. Real-time ultrasonic elastography is user-friendly with a high accuracy rate, thereby improving B mode ultrasound assessment, and the elastography sensitivity was 78.0%, specificity was 98.5% and overall accuracy was 93.8%. But, some studies were approved to demonstrate that UE with the proposed imaging classification had almost the same diagnostic performance as conventional ultrasonography in assessing breast lesions. UE does not have the potential to replace conventional B-mode ultrasonography for the detection of breast cancer, but may complement conventional ultrasonography to improve the diagnostic performance. However, there were few works to use UE in liver tumors. The elastography characteristics of liver tumors, with an obvious particularity, are not different with that of superficial tumors. In the current study, the real-time UE was evaluated in liver neoplasms, and compared with the results of postoperative pathological diagnosis. The objective of this study is to investigate the application value of UE in differential diagnosis of liver benign and malignant tumors.Methods1. Ultrasonic elastography in differentiating benign and malignant liver tumors.A total of 207 patients with 224 liver tumors were examined by conventional ultrasonography and ultrasonic elastography. All the patients underwent surgery and the lesions were confirmed by postoperative pathology. The results of conventional ultrasonography and ultrasonic elastography were compared with the pathological findings.2. Value of the strain ratio in the diagnosis of liver tumors by ultrasonic elastography. Ultrasonic elastography was performed in 145 patients with 157 liver tumors to obtain the strain images. The strain ratio of the tumors was then calculated. By comparing with the results of pathological diagnosis, the cut-off point for the strain ratio was determined using the receiver operating characteristic curve.Results1. Ultrasonic elastography in differentiating benign and malignant liver tumors.Pathological examination showed that 77 lesions were benign and 147 lesions were malignant. The benign lesions included 62 hepatic hemangioma, 6 focal nodular hyperplasia, 3 hepatic hemangioendothelioma, 2 hepatic angiomyolipoma and 4 liver abscess. The malignant lesions included 113 hepatocellular carcinoma, 11 intrahepatic cholangiocarcinoma, 8 mixed hepatic carcinoma and 15 metastatic liver carcinoma. The sensitivity, specificity, and accuracy of conventional ultrasonography for diagnosing malignant liver tumors were 74.8%,74.0% and 74.6%. However, the sensitivity, specificity, and accuracy of ultrasonoic elastography for diagnosing malignant liver tumors were 83.7%,87.0% and 84.8%.2. Value of the strain ratio in the diagnosis of liver tumors by ultrasonic elastography.The strain ratio of benign tumors was significantly lower than that of malignant ones (2.75±1.26vs8.33±4.45, P<0.01). The strain ratio of intrahepatic cholangiocarcinoma was highest, followed by metastatic liver carcinoma,hepatocellular carcinoma, and hepatic hemangioma. The cut-off point for strain ratio was set as 4.0. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value were 89.4%, 86.8%, 88.5%, 93.0% and 80.7%, respectively. The area under the curve was 0.941.Conclusions1. Ultrasonic elastography in differentiating benign and malignant liver tumors. The results indicate that the accuracy of ultrasonoic elastography for differentiating malignant from benign liver tumors is higher than that of conventional ultrasonography. Ultrasonic elastography is a new valuable method in diagnosing liver tumors and is helpful in differentiating between benign and malignant liver tumors.2. Value of the strain ratio in the diagnosis of liver tumors by ultrasonic elastography. Strain ratio could reflect the stiffness of liver tumors and represents a more objective diagnostic parameter for differentiation of benign and malignant liver tumors.