Ultrasound examination of the liver: Variations in the vascular anatomy.

The hepatic vasculature is highly complex. The hepatic artery (a branch of the celiac tripod) and the portal vein (formed by the confluence of the splenic and superior mesenteric veins) provide a dual blood supply while venous drainage is guaranteed by the hepatic veins. There are also numerous anatomic variants that can involve one or more of the system's three components.Hepatic artery variants are the least common. Ten types have been identified, including several that are fairly frequent and others that are quite rare, and the variation generally involves the extrahepatic portion of the vessel. Portal vein variants are found in around 20% of the population. They can involve the main portal trunk or segmental branches. Variants of the hepatic veins are the most common. They involve the number and course (supernumerary veins) or the number, course, and openings (accessory veins).Knowledge of portal vein and hepatic vein variants, which are extremely common, is of prime importance for precise localization of lesions. Hepatic artery variants are equally important for surgical treatment of hepatic disease, especially liver transplantation, where it is essential for preoperative workup and postoperative follow-up of the recipient as well as for assessment of potential donors.

Diagnosis of liver cirrhosis by transit-time analysis at contrast-enhanced ultrasonography.

PURPOSE: The aims of this prospective study were to evaluate analysis of sulfur-hexafluoride-filled microbubble contrast agent (Sonovue) transit times as a tool for differentiating liver cirrhosis from the noncirrhotic stage of liver disease and to compare its performance with that of conventional B-mode and Doppler ultrasonography (US). MATERIALS AND METHODS: Contrast-enhanced hepatic ultrasonography with the US contrast agent Sonovue was performed on 38 patients with diagnoses of hepatic cirrhosis based on unequivocal clinical signs or liver biopsy findings (Child-Pugh classes A in 19, B in 16 and C in three), 31 patients with noncirrhotic diffuse liver disease (biopsy confirmed) and 14 controls without diffuse liver disease. Time curves of hepatic-vein signal intensity were analysed using objective criteria to determine the time of enhancement onset (hepatic-vein arrival time) and peak enhancement (hepatic-vein peak enhancement). Accuracy in diagnosing cirrhosis was compared with that based on B-mode and Doppler data. RESULTS: Hepatic-vein arrival time in cirrhotic patients was significantly shorter (p < 0.01) than in noncirrhotic (chronic liver disease and controls) patients. Peak enhancement times in these three groups were not significantly different. An arrival-time cutoff of 17 s distinguished cirrhotic from noncirrhotic patients with high accuracy (100% sensitivity, 93.3% specificity, positive and negative predictive values 92.6% and 100%, respectively) and excellent reproducibility (kappa coefficients of 1.0 and 0.93 for intraand interobserver agreement). Contrast-enhanced US showed better sensitivity than the B-mode and Doppler data. CONCLUSIONS: Analysis of the time of onset of US contrast enhancement of the hepatic vein appears to be a potentially useful noninvasive supplement to conventional sonography and Doppler in the follow-up of patients with chronic diffuse liver disease.

Contrast-enhanced ultrasound to evaluate the severity of chronic hepatitis C.

BACKGROUND: Non-invasive techniques are being developed to assess the severity of liver disease. Haemodynamic changes in the hepatic circulation during the development of liver disease can be evaluated with contrast-enhanced ultrasound. AIM: To evaluate the possible correlation between ultrasound contrast-agent transit times and different stages of chronic hepatitis C. PATIENTS: Sixteen patients with clinically evident hepatitis C virus-related cirrhosis, 22 non-cirrhotic patients with chronic hepatitis C and 14 controls with no clinical evidence of liver disease were studied. METHODS: Contrast-enhanced hepatic ultrasonography was performed with a sulphur hexafluoride-filled microbubble contrast agent, and time curves of hepatic vein signal intensity were analysed to determine the time of enhancement onset (hepatic vein arrival time) and peak enhancement (hepatic vein peak enhancement). RESULTS: Hepatic vein arrival time in cirrhotic patients was significantly shorter (p<0.001) than in non-cirrhotic patients and controls. Within the group with chronic hepatitis C, METAVIR scores of fibrosis and necro-inflammatory changes had no significant effect on hepatic vein arrival times. CONCLUSION: Analysis of the time of onset of ultrasound contrast enhancement of the hepatic vein appears to be a simple, non-invasive method for reliably excluding cirrhosis with signs of portal hypertension, but not for assessing the severity of either chronic hepatitis C or cirrhosis.

Three-dimensional sonographic study of breast nodules.

PURPOSE: We examined breast nodules with three-dimensional (3D) sonography and power-Doppler to identify new parameters that might be useful in differentiating benign and malignant lesions. MATERIALS AND METHODS: Breast nodules in 34 women were examined with a Voluson-GE 730 scanner and a 7.5 MHz linear-array dedicated 3D probe. Each nodule was examined in the B-mode, and its vascular characteristics were evaluated with power-Doppler; 3D reconstruction was used in both studies. All examinations were performed by the same operator, who was unaware of the case characteristics. The examiner classified each lesion as benign or malignant based on B-mode appearance, margin characteristics, infiltration, and blood vessel distribution on power-Doppler; lesion volume was also calculated for T staging. Results were compared with those of biopsies, which were performed on all nodules after the sonographic examination. RESULTS: Biopsy findings revealed that 29 nodules were benign and 5 malignant. Based on the 3D sonographic examination, 27 lesions were considered benign, and 7 were classified as malignant. Two of the latter diagnoses were false-positives; there were no false negatives (specificity: 93.1%, sensitivity: 100%, accuracy: 94.1%). CONCLUSIONS: 3D sonography can be used to calculate lesional mass for T1 staging of malignant breast nodules. It can also reveal wall irregularities in benign lesions that are missed on two-dimensional (2D) scans and the limits of infiltration of malignant lesions. The 3D power-Doppler examination provides a panoramic full-length view of blood vessels supplying the nodule, and the number of vessels visualized with this approach is higher than that observed on 2D studies.

Ultrasound examination of the liver: Normal vascular anatomy.

Various treatments for liver diseases, including liver transplant (particularly partial liver resection from a living donor), treatment of liver tumors, and TIPS, require detailed knowledge of the complex vascular anatomy of the liver. The hepatic artery and portal vein provide the organ with a double blood supply whereas venous drainage is furnished by the hepatic veins.Multislice computed tomography and magnetic resonance imaging provide undeniably excellent information on these structures. On ultrasound, the inferior vena cava, the openings of the hepatic veins, and the main branch of the portal vein can always be visualized, but intrasegmental vessels (portal, arterial, accessory hepatic venous branches) can be only partially depicted and in some cases not at all.In spite of its difficulty and limitations, hepatic sonography is frequently unavoidable, particularly in critically ill patients, and the results are essential for defining diagnostic and therapeutic strategies. For this reason, a thorough knowledge of the sonographic features of hepatic vascular anatomy is indispensable.

Liver cirrhosis: evaluation of haemodynamic changes using an ultrasound contrast agent.

Liver cirrhosis is associated with haemodynamic changes. Using Levovist, we measured and compared Doppler signal arrival and peak enhancement times in the hepatic vein of patients with cirrhosis (n= 12) or chronic liver disease (n= 16) and in 12 healthy subjects. There were six patients with Child stage A, one patient with B, and five patients with C. The signal was recorded starting 20 s before contrast infusion until 2 h 20 min after its end. A software of the ultrasound (US) machine automatically sampled time-intensity values. Arrival times were significantly shorter (P < 0.001) in cirrhotic than non-cirrhotic (chronic liver disease + controls) and in patients with Child stage C compared with A. Differences in peak enhancement were weakly significant between cirrhotic and chronic patients (P < 0.04) and highly significant between the former and controls (P < 0.001), whereas differences between Child stages C and A were not significant (P > 0.05). Finally, cirrhotic patients had arrival times consistently shorter than 17 s. Automatic time-intensity curve analysis made measurements objective and conceptual error systematic, thus identifiable. Analysis of the passage of Levovist at the hepatic vein can thus become a non-invasive, well-tolerated and cost-effective diagnostic and monitoring tool in a larger number of patients with liver disease.

Ultrasonographic contrast agent: evaluation of time-intensity curves in the characterisation of solitary thyroid nodules.

PURPOSE: To evaluate whether the time-intensity curve can improve characterisation of solitary thyroid nodules. MATERIAL AND METHODS: From June to December 2000 we studied 61 patients (16 men and 45 women, mean age 46 years) with solitary thyroid nodules that were not associated with any important hormonal alteration and that showed poor tracer uptake at scintigraphy. We evaluated the Power Doppler vascular pattern before and after a 60" intravenous injection of 2.5 g of Levovist (diluted in 7 ml). The study lasted 5 minutes from the beginning of the infusion. Finally, the time-intensity curves were processed. All the nodules underwent fine needle aspiration biopsy (FNAB) and excision biopsy. RESULTS: Histology revealed 43 benign lesions and 18 malignant lesions. At contrast-enhanced Power Doppler 83.4% (15/18) of the malignant nodules were found to be hypervascularized, while 16.6% (3/18) were hypovascularized. Of the benign lesions, 90.7% (39/43) were hypervascularized, 9.3% (4/43) were hypovascularized. All the nodules, both hyper- and hypovascularized, displayed rapid and intense wash-in curves. By contrast, the wash-out curves were regular and monophasic in 40/43 (93%) benign lesions (36 hypervascularized and 4 hypovascularized lesions) and irregular and polyphasic in 16/18 (89%) malignant lesions (13 hypervascularized and 3 hypovascularized lesions); 3/43 (7%) benign nodules showed polyphasic wash-out and 2/18 malignant lesions (11%) showed monophasic wash-out. DISCUSSION AND CONCLUSIONS: Time-intensity curves, and particularly wash-out curves, provide useful information for the characterisation of solitary thyroid nodules. 93% of benign nodules (with regular vascularization) showed a monophasic pattern of the wash-out curve, while 89% of malignant nodules ("anarchical" vascularization) had polyphasic wash-out curves. This behaviour was observed in both hypervascularized and hypovascularized lesions. Our method proved to have a sensitivity of 88% and a specificity of 93%. The study of time-intensity curves could therefore enable us to differentiate between benign and malignant lesions and characterise hypovascularized malignant nodules which would not be observed without contrast agent.