Metastatic Liver Cancer Ultrasound Imaging Clinical Applications

Objectives: To evaluate capabilities of contrast-enhanced ultrasound with SonoVue in detection of liver metastases compared with conventional ultrasound. To investigate the perfusion and echogenicity of liver metastases using contrast tuned imaging and to analyse the hemodynamic parameters using QontraXt software.Methods: Thirty-five patients with known liver metastases were evaluated by conventional ultrasound and contrast tuned imaging(CnTI) gray scale ultrasound examination, respectively. The sizes, numbers of lesions found during CEUS were compared with those of conventional US. The perfusion patterns of liver metastases were evaluated. The enhancement type of the lesions were observed at arterial phase(0-40s), portal vein phase(41-120s) and late phase(after 120s). QontraXt software(AMID Italy) was used to estimate the following parameters: Peak(corresponging to blood volume of the lesion), Tp(time reaching maximum peak), Sharpness(corresponding to the velocity of perfusion and clearance of the lesion), AUC(corresponding to the blood flow of the lesion). These parameters were obtained from the time-intensity curves.Results: (l).In 35 patients, 182 liver metastases were found by US and the diameter of the largest lesion and the smallest lesion were 7.1cm and 0.8cm respectively; 386 liver metastases were found by CEUS and the diameter of the largest lesion and the smallest lesion were 7.1cm and 0.5cm, respectively. 204 more lesions were found by CEUS than by conventional US. The difference was statistically significant (P<0.05) . (2).During the arterial phase, the perfusion patterns of 76 major investigated lesions were in four types: 26.3%(20 lesions) enhanced in rim-like and the central region of the lesion was defected; 46.1%(35 lesions) enhanced in rim-like and the inside region of the lesion was homogeneous enhancement but was hypoechoic with respect to the surrounding liver; 11.8%(9 lesions) enhanced in rim-like and tortuous vessels were detected in the lesion; 15.8%(12 lesions) bolus-enhanced quickly and was hyperechonic compare to surrounding parenchyma. (3). A significant statistical difference (P<0.05 ) was found in the values of Peak, Tp, and AUC between the type of bolus-enhanced and other three types. The value of Peak of the type which central region of the lesion was defected was lower than that of other three types. The difference was statistically significant (P<0.05) . (4). In portal vein phase and late phase, all 76 lesions of 35 patients were hypoechoic in relation to the surrounding parenchyma. 54 lesions of 22 patients appear as completely defect in late phase.Conclusions: (1). CnTI markedly increase the contrast between the normal liver and the metastases and thus improve the detection. (2). To observe the enhancement patterns of liver metastases is helpful to characterization. (3). Quantitative analysis of the perfusion of liver metastases is helpful to diagnosis and could explain the reason of the enhancement patterns.