Early Identification of Residual Tumors following Microwave Ablation Using Contrast-Enhanced Ultrasonography in a Rabbit VX2 Liver Cancer Model

Objective. It is difficult to evaluate the ablation effect immediately after thermal ablation of liver cancer by clinical imaging methods, due to the immediate formation of an annular inflammatory reaction band (IRB). This study is aimed at exploring the early identification indicators of the IRB and residual tumor postmicrowave ablation (MVA) using contrast-enhanced ultrasonography (CEUS). Methods. MVA was used to inactivate part of the tumor nodules in rabbit VX2 liver cancer models, leading to the coexistence of the IRB with residual tumors. Quantitative analysis of the perfusion parameters of the tumor and ablation zone was performed using CEUS, followed by liver biopsy and VEGFR-2 immunohistochemical staining. Results. All rabbits successfully tolerated VX2 tumor inoculation and MVA operation. No statistically significant difference existed between the IRB vs. residual tumors, the IRB vs. junctional areas, and residual tumors postablation vs. VX2 tumors before ablation in regional blood volume, blood velocity, and blood flow estimated by parameters A, k, and A∗k of CEUS quantitative analysis. There was a statistically significant difference between the IRB and normal liver parenchyma in regional blood velocity and blood flow (p=0.005 and p=0.023, respectively). Normal liver parenchyma showed nonspecific VEGFR-2 staining, while VX2 tumor before ablation and residual tumor after ablation both showed positive VEGFR-2 staining; the necrosis zone showed negative staining by VEGFR-2 immunohistochemical staining. Conclusion. MVA had no significant effect on the residual tumor hemodynamics. The blood flow in the IRB increased significantly as compared to normal liver parenchyma, resembling tumor hemodynamic patterns. CEUS can detect residual tumors immediately postablation only when they protrude from the annular-shaped IRB. In addition, VEGFR-2 targeted CEUS may have a great potential for detecting residual tumor after thermal ablation of hepatocellular carcinoma.

Charactecteristics of Liver Tumors by means of ARFI-elastography

The purpose of this study was to determine the possibility of ARFI- elastography for diagnosis of tumors of the liver. The study included 95 patients with liver tumors. 22 patients were excluded from the study because of the deep location of the formation or the inability to measure the speed performance. Therefore the tumors in 73 patients were obtained by ARFI-elastography and analyzed. Verification of the diagnosis was achieved by histological examination of the material in 93% of cases and by MRI, CT in 7% of cases. Patients were divided by diagnosis: 4 – with benign tumors, 33 – with hepatocellular carcinoma, 4 – with cholangio-carcinoma, 19 – with metastatic colorectal cancer, 13 – with metastases of other cancer. Benign tumors included two focal nodular hyperplasia and hepatocellular adenoma, one cavernous hemangioma a large size. The obtained results were compared with normal liver parenchyma in 77 people. Average speed was: 2.83 m/s in the benign, 1.55 m/s in the normal liver parenchyma, 2.5 m/s at the nodes of hepatocellular carcinoma, 2.66 m/s at the nodes cholangio-carcinomar, 2.79 m/s in the metastasis of colorectal cancer, 2.79 m/s in the remaining metastases. Associated threshold value for the diagnosis of the majority of malignant tumors, it is necessary to consider the speed of over 2 m/s. Sensitivity groups ranged from 59% to 100% and a specificity of 70% to 86%. The results indicate higher speed performance parameters (mean, median, threshold values > 2.3 m/s) in benign tumors. This is due to a small group, as well as the large size of entities – from 5.0 to 24.0 cm, indicating that the long-term course of the disease with the development of fibrosis in them, so the stiffness of education becomes higher. These data prove that the quantitative elastography shear wave can be used as an additional diagnostic tool in oncology, but further accumulation of scientific data, since the values of the groups overlap.

CT with different doses of the hepatocyte-specific contrast medium fp 736-03

Purpose: to study the dose-response relationship in FP 736-03 (48 mg I/ml), a hepatocyte-specific contrast medium for CT of the liver Material and Methods: A nude-rat model of experimental hepatic metastases was used. CT of the liver was performed before and after i.v. injection of FP 736-03 at 4 different doses: 0.25, 0.5, 1.0 and 2.0 ml/kg b.w. Attenuation in the normal liver parenchyma and in the metastases was measured and plotted as a function of time Results: the enhancement of the normal liver parenchyma increased in the dose range studied. No increase was found in the metastases; the attenuation here remained constant during the observation period. the maximum enhancement values at doses of 0.25, 0.5, 1.0 and 2.0 ml/kg b.w. were (mean ± SD) 13.5±2.7, 30.1±4.2, 33.2±4.5 and 59.7±13.1 HU respectively