Characteristics of Focal Liver Lesions in Arterial Phase
on Contrast-enhanced Ultrasound and Contrast-
-enhanced Computed Tomography – Comparative Study*

Background Intrapancreatic accessory spleens (IPASs) are usually misdiagnosed as pancreatic neuroendocrine tumors (PNETs). Texture analysis is valuable in tumor detection, diagnosis, and staging. Purpose To identify the potential of texture features in differentiating IPASs from small hypervascular PNETs. Material and Methods Twenty-one patients with PNETs and 13 individuals with IPASs who underwent pretreatment dynamic contrast-enhanced computed tomography (CT) were retrospectively analyzed. The routine imaging features—such as location, size, margin, cystic or solid appearance, enhancement degree and pattern, and lymph node enlargement—were recorded. Texture features, such as entropy, skewness, kurtosis, and uniformity, on contrast-enhanced images were analyzed. Receiver operating characteristic (ROC) analysis was performed to differentiate IPASs from PNETs. Results No significant differences were observed in margin, enhancement degree (arterial and portal phase), lymph node enlargement, or size between PNETs and IPASs (all P > 0.05). However, IPASs usually showed heterogeneous enhancement at the arterial phase and the same degree of enhancement as the spleen at the portal phase, both of which were greater than those of PNETs (69% vs. 35%, P = 0.06; 100% vs. 29%, P = 0.04). Entropy and uniformity were significantly different between IPASs and PNETs at moderate (1.5) and high sigma values (2.5) (both P < 0.01). ROC analysis showed that uniformity at moderate and high sigma had the highest area under the curve (0.82 and 0.89) with better sensitivity (85.0–95.0%) and acceptable specificity (75.0–83.3%) for differentiating IPASs from PNETs. Conclusions Texture parameters have potential in differentiating IPASs from PNETs.

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Tips and Tricks in Contrast-Enhanced Ultrasound (CEUS) for the Characterization and Detection of Liver Malignancies

Ultraschall in der Medizin - European Journal of Ultrasound ◽

10.1055/a-0900-3962 ◽

2019 ◽

Vol 40 (04) ◽

pp. 404-424 ◽

Cited By ~ 6

Author(s):

Barbara Schellhaas ◽

Deike Strobel

Keyword(s):

Liver Cirrhosis ◽

Contrast Enhancement ◽

Late Phase ◽

Therapeutic Monitoring ◽

Arterial Phase ◽

Focal Liver Lesions ◽

Liver Lesions ◽

Contrast Enhanced Ultrasound ◽

Liver Malignancies ◽

Contrast Enhanced

AbstractContrast-enhanced ultrasound (CEUS) has a high diagnostic accuracy in the assessment of focal liver lesions. Clinical context (presence of liver cirrhosis, history of other malignancy versus incidental finding) is crucial for the correct interpretation of CEUS findings. CEUS has to be preceded by structured anamnesis and clinical examination as well as accurate B-mode sonography. Metastases are the most common malignant liver lesions in a non-cirrhotic liver. According to their contrast enhancement in the arterial phase, metastases are categorized as hyper- and hypo-vascular metastases. A common feature of all metastatic lesions is washout of the contrast agent in the portal venous or late phase. In the context of liver cirrhosis, > 95 % of focal liver lesions are hepatocellular carcinomas (HCCs). HCCs typically show arterial phase hyperenhancement, followed by mild and gradual contrast washout occurring very late in the late phase. For intrahepatic cholangiocellular carcinoma (ICC), the pattern of contrast enhancement in the arterial phase can vary. However, all ICCs typically show early and pronounced washout. Other liver malignancies like lymphoma, angiosarcoma, epithelioid hemangioendothelioma and others are very rare. Except for the contrast washout seen in all liver malignancies, they do not display pathognomonic enhancement patterns upon CEUS. Thus, biopsy is indispensable for definite diagnosis of the tumor entity. Furthermore, CEUS is used for the detection of metastases and therapeutic monitoring after local ablative procedures. The examination procedure differs slightly depending on the specific indication (characterization, detection).

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