Quantitative dynamic contrast-enhanced sonography of hepatic tumors

Abstract

Liver tumors are defined using quantitative dynamic contrast-enhanced ultrasound compared to histological diagnosis, respectively, long-term follow-ups. Forty-two focal liver lesions in 39 patients were examined by contrast harmonic imaging over a period of 2 min after bolus injection of 10-ml galactose-based contrast agent. Vascular enhancement was quantified by using a dedicated software that allowed us to place representative regions of interest (ROI) in the center of the lesion, in the complete lesion, in regular liver parenchyma and in representative liver vessels (artery, vein and portal vein). Peak enhancement was judged to be either in the arterial, portal venous or in the late phase of liver perfusion. The lesion was described as hypovascular, isovascular and hypervascular compared to liver parenchyma. Contrast uptake was described as centrifugal or centripetal and peripheral or homogenous, respectively. Characterization of the lesions was performed unenhanced and after contrast by four independent specialists unaware of histology. Diagnosis of malignancy was evaluated by using a receiver operating characteristic (ROC) analysis, also overall accuracy, average sensitivity, specificity and negative and positive predictive values were calculated. Interobserver agreement was defined by the Kappa statistics. Histologic examination revealed 29 malignant [hepatocellular carcinoma (HCC), n=11; cholangiocellular carcinoma (CCC), n=1; lymphoma, n=1; metastases, n=16)] and 7 benign [hemangioma, n=1; focal nodular hyperplasia (FNH), n=4, adenoma, n=2)] lesions. Six benign lesions (hemangioma n=1; FNH n=5) were proved by long-term follow-up. ROC analysis regarding the diagnosis of malignancy showed values from 0.43 to 0.62 (mean 0.57) before and from 0.70 to 0.80 (mean 0.75) after contrast agent, respectively. The average values for sensitivity, specificity, accuracy and negative and positive predictive values were 66, 26, 62, 45 and 73% unenhanced and 83, 49, 73, 65 and 82% after contrast, respectively. The interobserver agreement was 0.54 and 0.65 for unenhanced and enhanced examinations, respectively. Quantitative dynamic contrast-enhanced sonography improves the diagnosis of malignancy in liver lesions.

Intrahepatic cholangiocarcinoma and hepatocellular carcinoma: differential diagnosis with contrast-enhanced ultrasound

“…In the late phase, microbubbles washed out more conspicuously in all tumours compared with surrounding liver parenchyma [18,29], and this feature has a high degree of sensitivity and specificity in the diagnosis of malignant FLLs [16,30]. The detection rate of tumour vessels was lower in ICC (24%) in comparison with that in HCC (66%), which might be a clue in distinguishing between these two entities.…”

Evaluation of the Accuracy of Liver Lesion DCEUS Quantification With Respiratory Gating

“…Respiration can also obscure visual details in the qualitative assessment of liver lesion DCEUS such as the lesion's feeding vessels since different cross sections of the lesion appear on the imaging plane due to out-of-plane respiratory motion. A clinically used approach to compensate for the effects of respiratory motion is to direct patients to perform breath-holds [17]. However this approach can only by applied to patients that are able to hold their breath for a substantial period of time.…”

Role of parametric imaging in contrast-enhanced sonography of hepatic focal nodular hyperplasia

“…10 Klein et al have demonstrated the value of CEUS to improve diagnosis accuracy of focal liver lesions. 11 Those results were confirmed by Kim et al in diffuse liver disease. 12 However, until now only 1 study has been published in which the perfusion pattern of focal liver lesions is determined by quantifying the signal enhancement after bolus injection of a galactose-based contrast agent.…”

“…4,7,9,18 The first studies using ultrasound contrast agents and color Doppler sonography were limitated by blooming artifacts. [7][8][9]11 The introduction of second-generation agents has improved the characterization of focal liver lesions by reducing artifacts (eg, blooming or motion artifacts) depicting tiny vessels within a lesion as well as progression of contrast within the lesion. 13,17,[19][20][21][22][23][24] Our study confirms the value of CEUS in the depiction of specific vascular patterns for FNH, namely a central artery, spoke-wheel pattern, and a global enhancement at the end of the arterial phase, regardless of the size of the lesion.…”