Characterization of liver lesions by real-time contrast-enhanced ultrasonography.

OBJECTIVE: The aim of this study was to identify the most common patterns of various common liver lesions at real-time contrast-enhanced ultrasonography with second-generation contrast agents and their role in the differentiation of malignant from benign lesions. PATIENTS AND METHODS: The enhancement pattern in the arterial phase and its modifications in subsequent portal and sinusoidal phases were separately evaluated in (i) 171 liver lesions detected at conventional ultrasonography in 125 noncirrhotic patients (87 metastases, six cholangiocellular carcinoma, 38 focal nodular hyperplasia, 30 hemangiomas, seven focal fatty sparing/changes, two hepatocellular adenomas and one hepatocellular carcinoma) and (ii) 75 lesions detected in 67 cirrhotic patients (66 hepatocellular carcinoma and nine dysplastic nodules). The final diagnosis was made by contrast-enhanced helical computed tomography and/or magnetic resonance imaging or by ultrasonography-guided biopsy when the diagnosis was equivocal at conventional imaging techniques (45 lesions). RESULTS: In noncirrhotic patients, the hypoechoic pattern in portal and sinusoidal phase (rapid washout) or the markedly hypoechoic or anechoic pattern in sinusoidal phase (marked late washout) showed a sensitivity, specificity and accuracy of 96.8, 100 and 98.2% for the diagnosis of malignancy. In cirrhotic patients, early arterial enhancement showed a sensitivity of 93.9% for the diagnosis of malignancy, with a specificity as low as 55.5% given the presence of arterial enhancement in 5/9 nodules resulted dysplastic at histological analysis. CONCLUSION: Real-time contrast-enhanced ultrasonography provides sensitive and specific criteria for the differential diagnosis between benign and malignant liver lesions, and in most cases it may replace more expensive and invasive imaging techniques.

Echo-enhanced ultrasonography: is it the future gold standard of imaging in acute pancreatitis?

We report the imaging of a patient in whom the diagnosis of acute pancreatitis and the assessment of disease severity was carried out using echo-enhanced ultrasonography. Contrast-enhanced computed tomography confirmed the echo-enhanced ultrasonography picture. Echo-enhanced ultrasonography may become the imaging technique of choice in assessing the severity of acute pancreatitis since it is easy to perform, safe and lends itself to emergency situations. Most importantly, this technique should be also useful for following-up patients and it may be also an alternative to MRI in those patients in whom contrast-enhanced computed tomography cannot be carried out.

Characterization of small nodules in cirrhosis by assessment of vascularity: the problem of hypovascular hepatocellular carcinoma.

In a prospective study, we examined the impact of arterial hypervascularity, as established by the European Association for the Study of the Liver (EASL) recommendations, as a criterion for characterizing small (1-3 cm) nodules in cirrhosis. A total of 72 nodules (1-2 cm, n = 41; 2.1-3 cm, n = 31) detected by ultrasonography in 59 patients with cirrhosis were included in the study. When coincidental arterial hypervascularity was detected at contrast perfusional ultrasonography and helical computed tomography, the lesion was considered to be hepatocellular carcinoma (HCC) according to EASL criteria. When one or both techniques showed negative results, ultrasound-guided biopsy was performed. In cases with negative results for malignancy or high-grade dysplasia, biopsy was repeated when an increase in size was detected at the 3-month follow-up examination. Coincidental hypervascularity was found in 44 of 72 nodules (61%; 44% of 1-2-cm nodules and 84% of 2-3-cm nodules). Fourteen nodules (19.4%) had negative results with both techniques (hypovascular nodules). Biopsy showed HCC in 5 hypovascular nodules and in 11 of 14 nodules with hypervascularity using only one technique. All nodules larger than 2 cm finally resulted to be HCC. Not satisfying the EASL imaging criteria for diagnosis were 38% of HCCs 1 to 2 cm (17% hypovascular) and 16% of those 2 to 3 cm (none hypovascular). In conclusion, the noninvasive EASL criteria for diagnosis of HCC are satisfied in only 61% of small nodules in cirrhosis; thus, biopsy frequently is required in this setting. Relying on imaging techniques in nodules of 1 to 2 cm would miss the diagnosis of HCC in up to 38% of cases. Any nodule larger than 2 cm should be regarded as highly suspicious for HCC.

Usefulness of contrast-enhanced perfusional sonography in the assessment of hepatocellular carcinoma hypervascular at spiral computed tomography.

BACKGROUND/AIMS: Diagnosis of hepatocellular carcinoma (HCC) relies strongly on the detection of hypervascularity in the arterial phase and, in this setting, spiral computed tomography (CT) is the most widely used method. This prospective study aimed to investigate the usefulness of low mechanical index harmonic ultrasound (US), using a second generation contrast-enhanced technique, in the assessment of vascular pattern of HCC shown to be hypervascular at spiral CT. METHODS: A total of 79 cirrhotic patients with 103 nodules (mean+/-SD 28+/-13 mm) with arterial hypervascularity at spiral CT were studied. US examination was performed by perfusional sonography, using a new dedicated technology (CnTI-Esaote trade mark ), operating at low mechanical index, after injection of a second generation contrast agent (SonoVue trade mark -Bracco), allowing detection of tumoral flow during arterial phase. RESULTS: Selective arterial enhancement on perfusional sonography was observed in 94 /103 nodules (91.3%), with a sensitivity of 66.6, 87.5, 91.7, and 97.3% in nodules 123 cm respectively. CONCLUSIONS: Perfusional sonography shows good diagnostic agreement with spiral CT in hypervascular HCC and may be proposed for the immediate vascular characterization of nodules detected at US and used as second imaging technique to confirm hypervascularity in cirrhotic nodules.

Liver metastases from rectal carcinoma: disease progression during chemotherapy despite loss of arterial-phase hypervascularity on real-time contrast-enhanced harmonic sonography at low acoustic energy.

We used a new sonographic technique, real-time contrast-enhanced harmonic sonography at low acoustic energy, to evaluate liver perfusion and liver metastases from colorectal cancer in a 73-year-old woman after chemotherapy. After 6 weeks of chemotherapy, liver metastases that had been clearly visible on conventional sonography before chemotherapy were no longer detectable on conventional sonography but were still evident on contrast-enhanced sonography. At about 6 months after initiation of chemotherapy, the lesions were all visible again on conventional sonography and had become significantly larger, although some no longer showed contrast enhancement during the arterial phase. In this case, changes in arterial perfusion over time did not parallel the response of liver metastases to chemotherapy.

Effect of Levovist on splanchnic hemodynamics in cirrhotic patients.

This study was aimed to assess the effect of Levovist on Doppler parameters of splanchnic hemodynamics. A total of 12 patients with cirrhosis and 12 healthy subjects underwent Doppler ultrasound (US) examination of the portal vein and of the hepatic, splenic and superior mesenteric arteries before, 5 to 8 and 12 to 15 min after the start of an 8-min long IV infusion of 2.5 g of Levovist. Mean velocity and mean diameter were calculated for the portal vein. Resistance index was determined for the arteries. A significant increase of resistance index was observed in the hepatic (0.80 +/- 0.07 vs. 0.71 +/- 0.06; p < 0.01) and splenic arteries (0.72 +/- 0.06 vs. 0.64 +/- 0.06; p < 0.01) 5 to 8 min after contrast agent injection in patients with cirrhosis, but not in controls. Neither portal vein diameter nor portal flow mean velocity changed during the test in both controls and cirrhotic patients. This effect might be related to a selective trapping of microbubbles in the altered hepatic and splenic microvasculature in patients with cirrhosis rather than being artefactual. It might have implications on harmonic imaging US protocols designed to image the cirrhotic liver in the early arterial phase.