OBJECTIVE: To analyze the contrast-enhancement patterns obtained at pulseinversion harmonic imaging (PIHI) of focal hepatic lesions, and to thus determine tumor vascularity and the acoustic emission effect. MATERIALS AND METHODS: We reviewed pulse-inversion images in 90 consecutive patients with focal hepatic lesions, namely hepatocellular carcinoma (HCC) (n=43), metastases (n=30), and hemangioma (n=17). Vascular and delayed phase images were obtained immediately and five minutes following the injection of a microbubble contrast agent. Tumoral vascularity at vascular phase imaging and the acoustic emission effect at delayed phase imaging were each classified as one of four patterns. RESULTS: Vascular phase images depicted internal vessels in 93% of HCCs, marginal vessels in 83% of metastases, and peripheral nodular enhancement in 71% of hemangiomas. Delayed phase images showed inhomogeneous enhancement in 86% of HCCs; hypoechoic, decreased enhancement in 93% of metastases; and hypoechoic and reversed echogenicity in 65% of hemangiomas. Vascular and delayed phase enhancement patterns were associated with a specificity of 91% or greater, and 92% or greater, respectively, and with positive predictive values of 71% or greater, and 85% or greater, respectively. CONCLUSION: Contrast-enhancement patterns depicting tumoral vascularity and the acoustic emission effect at PIHI can help differentiate focal hepatic lesions.
Adult ; Aged ; Carcinoma, Hepatocellular/blood supply/*ultrasonography ; Colon/pathology ; Contrast Media/*administration & dosage ; Diagnosis, Differential ; Female ; Hemangioma/blood supply/*ultrasonography ; Human ; Image Enhancement/*methods ; Liver/pathology/ultrasonography ; Liver Neoplasms/blood supply/secondary/*ultrasonography ; Lung/pathology ; Male ; *Microbubbles ; Middle Aged ; Pancreas/pathology ; Polysaccharides/administration & dosage/diagnostic use ; Reproducibility of Results ; Retrospective Studies ; Sensitivity and Specificity ; Stomach/pathology ; Support, Non-U.S. Gov't

BACKGROUND/AIMS: To evaluate the enhancement patterns of liver metastases and their influencing factors using dynamic contrast-enhanced ultrasound (CEUS). METHODS: A total of 240 patients (139 male and 101 female; 58.5±11.2 years of age) diagnosed with liver metastases in our hospital were enrolled in this study to evaluate tumor characteristics using CEUS. A comparison of enhancement patterns with tumor size and primary tumor type was performed using the chi-square test. The differences between quantitative variables were evaluated with the independent-sample t-test and one-way analysis of variance. RESULTS: The enhancement patterns of liver metastases on CEUS were categorized as diffuse homogeneous hyperenhancement (133/240, 55.4%), rim-like hyperenhancement (80/240, 33.3%), heterogeneous hyperenhancement (10/240, 4.2%), and isoenhancement (17/240, 7.1%). There were significant differences in the enhancement patterns during the arterial phase based on the nodule size (p=0.001). A total of 231 of the nodules showed complete washout during the portal phase, and 237 nodules were hypoenhanced during the delayed phase. The washout time was correlated with tumor vascularity, with a longer washout time observed in hypervascular metastases compared to hypovascular metastases (p=0.033). CONCLUSIONS: Diffuse homogeneous hyperenhancement followed by rapid washout was the most common enhancement pattern of liver metastases on CEUS and was affected by the nodule size and tumor vascularity. Small metastases were prone to show diffuse homogeneous hyperenhancement. Hyper-vascular metastases showed a significantly longer washout time compared to hypovascular metastases.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Contrast Media/*therapeutic use ; Female ; Humans ; Liver/diagnostic imaging/pathology ; Liver Neoplasms/blood supply/*diagnostic imaging/secondary ; Male ; Middle Aged ; Neovascularization, Pathologic/diagnostic imaging ; Ultrasonography/*methods ; Young Adult