Contrast media-enhanced power Doppler sonography for evaluation of hemangiomas and malignant tumors in the liver

Contrast-enhanced US for characterization of focal liver lesions: a comprehensive meta-analysis

OBJECTIVES

This meta-analysis was performed to evaluate the accuracy of contrast-enhanced ultrasound (CEUS) in differentiating malignant from benign focal liver lesions (FLLs).

METHODS

Cochrane Library, PubMed and Web of Science databases were systematically searched and checked for studies using CEUS in characterization of FLLs. Data necessary to construct 2×2 contingency tables were extracted from included studies. The QUADAS tool was utilized to assess the methodologic quality of the studies. Meta-analysis included data pooling, subgroup analyses, meta-regression and investigation of publication bias was comprehensively performed.

RESULTS

Fifty-seven studies were included in this meta-analysis and the overall diagnostic accuracy in characterization of FLLs was as follows: pooled sensitivity, 0.92 (95%CI: 0.91-0.93); pooled specificity, 0.87 (95%CI: 0.86-0.88); diagnostic odds ratio, 104.20 (95%CI: 70.42-154.16). Subgroup analysis indicated higher diagnostic accuracy of the second-generation contrast agents (CAs) than the first-generation CA (Levovist; DOR: 118.27 vs. 62.78). Furthermore, Sonazoid demonstrated the highest diagnostic accuracy among three major CAs (SonoVue, Levovist and Sonazoid; DOR: 118.82 vs. 62.78 vs. 227.39). No potential publication bias was observed of the included studies.

CONCLUSION

CEUS is an accurate tool to stratify the risk of malignancy in FLLs. The second-generation CAs, especially Sonazoid may greatly improve diagnostic performance.

KEY POINTS

• CEUS shows excellent diagnostic accuracy in differentiating malignant from benign FLLs. • The second-generation CAs have higher diagnostic accuracy than first-generation CAs. • Sonazoid demonstrates the highest diagnostic accuracy among three major CAs.

Renal ultrasonography in critically ill patients

Acute renal failure is a sudden and sustained decrease in the glomerular filtration rate associated with a loss of excretory function and the accumulation of metabolic waste products and water. It leads to an increase in serum urea and creatinine, usually with a decrease in urine output. Although routine surveillance of patients by means of laboratory examinations has been well defined, very little is known about renal imaging. Modern technology has provided a large number of sophisticated monitoring systems. Ultrasonography with color-Doppler study of the kidneys may be indicated as a possible monitor of renal perfusion. Ultrasonography is often used as the initial imaging procedure in the examination of patients with renal failure. Aside from excluding hydronephrosis, it is well recognized in characterizing the type of renal disease, especially in an acute setting. This article describes the use of ultrasound to achieve the proper diagnosis of acute renal diseases and to enable the appropriate and early assessment of these patients in intensive care units.

Potential for Differential Diagnosis with Gadolinium-Ethoxybenzyl-Diethylenetriamine Pentaacetic Acid-Enhanced Magnetic Resonance Imaging in Experimental Hepatic Tumors

RATIONALE AND OBJECTIVES

To investigate whether dynamic and delayed magnetic resonance imaging (MRI) with gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA), a hepatobiliary MRI contrast agent, has potential for the differential diagnosis of experimental hepatic tumors.

METHODS

Twelve male rats received N-nitrosomorpholine solution as drinking water to induce hepatic tumors. After injection of Gd-EOB-DTPA, rats were subjected to dynamic and delayed MRI. The relative enhancement (RE) was calculated, and the time of the maximum RE (Tmax) was evaluated. After MRI, liver was histologically analyzed.

RESULTS

One hundred sixty-three hepatic tumors 3-12 mm in diameter were induced after 18 weeks of treatment with 0.01 wt/vol% of N-nitrosomorpholine, and 81 of them were evaluated. The RE in hyperplastic nodules (HPNs) was significantly higher than that in moderately or poorly differentiated hepatocellular carcinomas (HCCs) in the late phase, whereas there was no significant difference in RE between well-differentiated HCCs and HPNs. The average Tmax in HPNs was about 13 minutes, whereas that of each differentiated HCCs was about 1 minute.

CONCLUSIONS

It was possible to differentiate benign HPNs and malignant HCCs (especially well-differentiated HCCs) by evaluating the change of RE or comparison of Tmax with Gd-EOB-DTPA-enhanced MRI.

Small hepatocellular carcinomas in patients with liver cirrhosis: potentials and limitations of contrast-enhanced power Doppler sonography

Detection and characterization of focal liver lesions are critical for patients with liver cirrhosis. The potential of contrast-enhanced sonography in the characterization of focal liver lesions is well established in the literature. However, prospective studies in the assessment of patients with suspected hepatocellular carcinoma (HCC) in liver cirrhosis are rare. B-mode imaging often cannot differentiate small focal lesions in cirrhotic livers. Also, power Doppler is not capable of characterizing small focal lesions in cirrhosis. Contrast-enhanced sonography with a first-generation enhancer seems to improve the accuracy of diagnosis of small HCC. The differentiation of HCC and dysplastic nodules is notoriously difficult. In addition, other arterial hypervascularized liver lesions should be considered, depending on the clinical background. The limitations and drawbacks of contrast-enhanced sonography should be considered. All imaging methods are of limited value in the detection of solid liver lesions smaller than 1 cm.