Evaluation of portal venous velocity with Doppler ultrasound in patients with nonalcoholic fatty liver disease

Non-invasive diagnosis of non-alcoholic fatty liver disease using an algorithm combining clinical indexes and ultrasonographic measures

INTRODUCTION AND OBJECTIVE

Non-Alcoholic Fatty Liver Disease (NAFLD) is a metabolic liver disease related to insulin resistance, which requires invasive methods for diagnosis. The aim of this study was to analyze whether the use of an algorithm involving both clinical indices and hepatic ultrasound measurements improves the accuracy for the non-invasive diagnosis of NAFLD.

PATIENTS AND METHODS

Cross-sectional study with patients undergoing elective cholecystectomy. We collected anthropometric, metabolic, liver biopsy, and liver ultrasonography data. We calculated unpaired t-test and Pearson's coefficient, and areas under the receiver-operating characteristic curves (AUROC) for the Fatty Liver Index (FLI), Lipid Accumulation Product (LAP) indexes, right liver index diameter, and for predictive models constructed with discriminant analysis.

RESULTS

One hundred patients in groups with and without NAFLD. FLI, LAP, right and caudate liver lobe diameters, and congestion index were higher in NAFLD group (p = 0.011, p = 0.011, p = 0.001, p = 0.027, p = 0.009). The right liver lobe diameter had the highest AUROC. Predictive models that combined sensitivity and specificity for the clinical indexes and liver ultrasound had an AUROC over 0.7.

CONCLUSION

The ultrasonography measure of right liver lobe diameter by itself can reliably identify patients with NAFLD with a good sensitivity and specificity, however, this can be improved by adding the LAP mathematical index in our population.

Changes in the Velocity of Blood in the Portal Vein in Mild Acute Pancreatitis-A Preliminary Clinical Study

Background and objective: Portal vein thrombosis is associated with a decrease in the main blood velocity in this vessel. While most studies examine etiological factors of portal vein thrombosis after its occurrence, we aimed to evaluate portal vessels and assess whether mild acute pancreatitis affects blood flow in the portal vein and increases the risk of thrombosis. Materials and methods: This prospective single centered follow-up study enrolled 66 adult participants. Fifty of them were diagnosed with mild acute pancreatitis based on the Revised Atlanta classification, and 16 healthy participants formed the control group. All participants were examined three times. The first examination was carried out at the beginning of the disease and the next two at three-month intervals. Blood samples were taken and color Doppler ultrasound performed the first time, whereas ultrasound alone was performed during the second and third visits. Mean and maximal blood velocities and resistivity index in the main portal vein and its left and right branches were evaluated. Results: Mean velocity of the blood flow in the main portal vein and its right and left branches was not significantly different from healthy individuals during the acute pancreatitis phase: 23.1 ± 8.5 cm/s vs. 24.5 ± 8.2 cm/s (p = 0.827); 16.4 ± 7.9 cm/s vs. 16.4 ± 8.1 cm/s (p = 1.000); and 8 ± 3.4 cm/s vs. 7.4 ± 2.5 cm/s (p = 0.826), respectively. The same was observed when comparing the maximal blood flow velocity: 67.9 ± 29 cm/s vs. 67.5 ± 21 cm/s (p > 0.05); 45.4 ± 27 cm/s vs. 44 ± 23.8 cm/s (p = 0.853); and 22.2 ± 9.8 cm/s vs. 20 ± 7.3 cm/s (p = 0.926), respectively. Changes in venous blood velocities were not significant during the follow-up period in separate study groups. Conclusions: Portal blood flow velocities do not change during mild acute pancreatitis in the inflammatory and postinflammatory periods. This observation suggests that mild acute pancreatitis does not increase the risk of portal vein thrombosis.

The Doppler ultrasonographic evaluation of hemodynamic changes in hepatic vascular structures in patients with hepatosteatosis

Background

The hemodynamic changes in hepatic vascular structures of hepatosteatosis patients were examined using Doppler ultrasonography.

Material/Methods

Ninety hepatosteatosis patients, classified as mild, moderate or severe, and 30 healthy volunteers were included in this 120-person study. The height, weight, liver size, blood lipids and blood liver function tests of the subjects were measured. Those values were compared in the patient and control groups. In the patient and control groups, color duplex Doppler ultrasonography was used to examine portal vein peak velocity, portal vein flow volume, hepatic artery resistive index (RI), hepatic artery pulsatility index (PI) and hepatic artery flow volume.

Results

Similarly to the degree of hepatosteatosis, increases in body mass index, liver size, liver enzyme levels and blood lipid levels were statistically significant (p<0.05). While the difference in portal vein peak velocity in the hepatosteatosis and control groups was not statistically significant, there was an increasing reduction in the degree of steatosis (p>0.05). As the degree of hepatosteatosis increased, there was a reduction in hepatic artery flow volume, portal vein flow volume and total flow volume that was not statistically significant. In the mild hepatosteatosis group, hepatic artery RI and PI values were statistically significantly lower than in the other groups (p<0.05). In the severe hepatosteatosis group, although the hepatic artery RI and PI values were not statistically significant, there was a minimal increase compared to the other groups.

Conclusions

It is believed that those results were caused by a reduction in liver compliance and hepatic vascular compliance, in addition to resistance increase in vascular structures.

Evaluation of hepatic tissue blood flow using xenon computed tomography with fibrosis progression in nonalcoholic fatty liver disease: comparison with chronic hepatitis C

AIMS

The present study evaluated the utility of xenon computed tomography (Xe-CT) as a noninvasive diagnostic procedure for the measurement of hepatic tissue blood flow (TBF) in patients with nonalcoholic fatty liver disease (NAFLD) or chronic hepatitis C (CH-C).

METHODS

Xe-CT was performed in 93 patients with NAFLD and in 109 patients with CH-C. Subjects were classified into one of three groups, based on fibrosis stage: group 1, no bridging fibrosis; group 2, bridging fibrosis; and group 3, liver cirrhosis. Correlations between hepatic TBFs in each fibrosis stage were examined.

RESULTS

In group 1, portal venous TBF (PVTBF), hepatic arterial (HATBF), and total hepatic TBF (THTBF) were significantly lower in patients with in nonalcoholic steatohepatitis (NASH) than in those with CH-C (p < 0.001, p < 0.05, p < 0.001, respectively). In group 2, PVTBF and THTBF were significantly lower in patients with in NASH than in those with CH-C (p < 0.001, p < 0.05, respectively). In group 3, hepatic TBFs were not significantly different when comparing patients with NASH and those with CH-C.

CONCLUSIONS

PVTBF decreased due to fat infiltration. Therefore, hemodynamic changes occur relatively earlier in NAFLD than in CH-C. Patients with NASH should be monitored carefully for portal hypertensive complications in the early fibrosis stage.

Impact of anthropometrical parameters on portal vein diameter and liver size in a subset of Karachi based population

OBJECTIVE

The purpose was to study the impact of anthropometrical parameters on portal vein diameter and liver size by ultrasound in a subset of Karachi population.

METHODS

Four hundred and fifty nine apparently healthy subjects were included in this cross sectional study. After recording weight and height of each subject, Portal vein diameter and both liver lobes were measured by gray scale ultrasonography. Students T test and ANOVA were applied for statistical analyses.

RESULTS

With increasing age, portal vein diameter and right lobe of liver increased significantly (p value < 0.001). Increase in portal vein diameter was also observed with rise in body mass index (0.8 cm in underweight - 1.1 cm in obese subjects). Sizes of right and left liver lobes also increased with a rise in body mass index (p value < 0.001 and 0.001). Gender, however, did not have any effect on portal vein diameter and liver size.

CONCLUSION

Age and body mass index are reliable parameters to consider for avoiding false positive diagnosis of hepatomegaly and portal hypertension. Knowing the right and left liver size with respect to anthropometrical measurements also assist a clinician in selecting a subject for liver transplantation.

Diffusion analysis with triexponential function in hepatic steatosis

Our purpose was to assess the influence of liver steatosis on diffusion by triexponential analysis. Thirty-three patients underwent diffusion-weighted magnetic resonance imaging with multiple b values for perfusion-related diffusion, fast free diffusion, and slow restricted diffusion coefficients (D p, D f, D s) and fractions (F p, F f, F s). They also underwent dual-echo gradient-echo imaging for measurement of the hepatic fat fraction (HFF). Of these, 13 patients were included in the control group and 20 in the fatty liver group with HFF >5 %. The parameters of the two groups were compared by use of the Mann-Whitney U test. The relationships between diffusion coefficients and HFFs were assessed by use of the Pearson correlation. D p and D f were reduced significantly in the steatotic liver group compared with those in the control group (D p = 27.72 ± 6.61 × 10(-3) vs. 33.33 ± 6.47 × 10(-3) mm(2)/s, P = 0.0072; D f = 1.70 ± 0.53 × 10(-3) vs. 2.06 ± 0.40 × 10(-3) mm(2)/s, P = 0.0224). There were no significant differences in the other parameters between the two groups. Furthermore, D p and D f were correlated with HFF (P < 0.0001, r = -0.64 and P = 0.0008, r = -0.56, respectively). Decreased liver perfusion in steatosis caused the reduction in D p, and extracellular fat accumulation and intracellular fat droplets in steatosis led to the reduction in D f. Thus, the influence of hepatic steatosis should be taken into consideration when triexponential function analysis is used for assessment of diffuse liver disease.

Branched-chain amino acids alleviate nonalcoholic steatohepatitis in rats

Nonalcoholic steatohepatitis (NASH) is a prevalent disease in countries around the world. The branched-chain amino acids (BCAAs) leucine, isoleucine, and valine cannot be synthesized by the body and have been shown to promote muscle buildup; thus, it is logical to suggest that BCAAs can reduce fat deposition in the body. We used gonadectomized rats fed a high-fat diet to investigate the effects of BCAAs on lipid metabolism over an 8-week experimental period. Body composition, tissue histology, plasma lipid indices, and hormone levels were examined. We demonstrated that the body weights of rats were not significantly decreased but the mesenteric fat was significantly decreased (p < 0.05) in BCAA-treated rats. In addition, BCAAs decreased plasma lipid levels and fat deposition in the liver. At week 4, when the untreated rats displayed macrovesicular steatosis, BCAA-treated rats had only macrovesicular droplets in their hepatocytes. At week 8, when the untreated rat livers displayed profound inflammation and cirrhosis, BCAA-treated rat livers remained in the macrovesicular stage of steatosis. BCAAs induced higher blood glucose and plasma insulin levels (p < 0.05). BCAAs also improved liver blood flow by increasing mean arterial blood pressure and decreasing portal pressure, which helped delay the change in blood flow pattern to that of cirrhosis. BCAAs also induced the skeletal muscle to express higher levels of branched-chain α-keto acid dehydrogenase E1α, which indicates an enhanced metabolic capacity of BCAAs in muscle tissue. This study clearly demonstrates the effects of BCAAs on the amelioration of fat deposition in rats fed a high-fat diet.