Contrast enhanced ultrasound of hepatocellular carcinoma

Sonazoid(Daiichi Sankyo,Tokyo,Japan),a secondgeneration of a lipid-stabilized suspension of a perfluorobutane gas microbubble contrast agent,has been used clinically in patients with liver tumors and for harmonic gray-scale ultrasonography(US)in Japan since January 2007.Sonazoid-enhanced US has two phases of contrast enhancement:vascular and late.In the late phase of Sonazoid-enhanced US,we scanned the whole liver using this modality at a low mechanical index(MI)without destroying the microbubbles, and this method allows detection of small viable hepatocellular carcinoma(HCC)lesions which cannot be detected by conventional US as perfusion defects in the late phase.Re-injection of Sonazoid into an HCC lesion which previously showed a perfusion defect in the late phase is useful for confirming blood flow intothe defects.High MI intermittent imaging at 2 frames per second in the late phase is also helpful in differentiation between necrosis and viable hypervascular HCC lesions.Sonazoid-enhanced US by the coded harmonic angio mode at a high MI not only allows clear observation of tumor vessels and tumor enhancement, but also permits automatic scanning with Sonazoidenhanced three dimensional(3D)US.Fusion images combining US with contrast-enhanced CT or contrastenhanced MRI have made it easy to detect typical or atypical HCC lesions.By these methods,Sonazoidenhanced US can characterize liver tumors,grade HCC lesions histologically,recognize HCC dedifferentiation, evaluate the efficacy of ablation therapy or transcatheter arterial embolization,and guide ablation therapy for unresectable HCC.This article reviews the current developments and applications of Sonazoid-enhanced US and Sonazoid-enhanced 3D US for diagnosing and treating hepatic lesions,especially HCC.

Differentiation of focal liver lesions using three-dimensional ultrasonography: Retrospective and prospective studies

AIM: To differentiate focal liver lesions based on enhancement patterns using three-dimensional ultrasonography (3D US) with perflubutane-based contrast agent.METHODS: Two hundred and eighty two patients with focal liver lesions,including 168 hepatocellular carcinomas (HCCs),63 metastases,40 hemangiomas and 11 focal nodular hyperplasias (FNHs),were examined by 3D US with perflubutane-based contrast agent.Tomographic ultrasound images and sonographic angiograms were reconstructed.Among 282 lesions,enhancement patterns of 163 lesions between January 2007 and October 2007 were analyzed retrospectively.Then from November 2007 to May 2008,compared with contrast-enhanced (CE) 2D US,CE 3D US was performed on 119 lesions for prospective differential diagnosis.Sensitivity,specificity,area under receiver operating characteristic curve (Az) and inter-reader agreement were assessed.RESULTS: With the tridimensional view,dominant enhancement patterns were revealed as diffuse enhancement or peripheral ring-like enhancement,followed with washout change for HCCs or metastases,respectively,and peripheral nodular enhancement or diffuse enhancement with spoke-wheel arteries,followed by persistent enhancement for hemangiomas or FNHs,respectively.At CE 3D US,the prospective differentiation of lesions showed sensitivity 92% (mean for two readers),specificity 91% and Az value 0.95 for HCCs,84%,97%,and 0.95 for metastases,91%,98%,and 0.98 for hemangiomas and 80%,99%,and 0.99 for FNHs,respectively,while good to excellent inter-reader agreement was achieved.No significant difference exists between prospective diagnosis accuracy at CE 3D US and that at CE 2D US.CONCLUSION: CE 3D US provides a spatial perspective for liver tumor enhancement,and could help in differentiating focal liver lesions.

Case of a tumor comprising gastric cancer and duodenal neuroendocrine tumor

The present report describes a rare case of a tumor composed of early gastric cancer and a duodenal neuroendocrine tumor(NET). A 78-year-old woman underwent esophagogastroduodenoscopy at a local institution for screening of the upper gastrointestinal tract which revealed a protruded tumor through the pyloric ring from the pyloric antrum. The tumor was too large to treat at the facility; consequently, she was referred to our hospital for further management. Esophagogastroduodenoscopy with tumor biopsy of the lesion revealed the diagnosis of early gastric cancer. Endoscopic submucosal dissection was performed with sufficient free margins in both vertical and horizontal directions. Histopathological findings showed NET confined to the submucosal layer and covered by welldifferentiated adenocarcinoma. Immunohistochemical stainings showed that the two lesions existed continuously. While the possibility of a collision cancer was considered, it was suggested that the two lesions existed continuously. Finally, the tumor was diagnosed as gastric cancer composed of duodenal NET G1, with a lymphatic invasion of NET component.