Effects of fat accumulation in the liver on hemodynamic variables assessed by Doppler ultrasonography

The correlation between metabolic dysfunction-associated steatotic liver disease (MASLD) grades and hemodynamic alterations of the portal, hepatic, and splenic vein and spleen size

INTRODUCTION

Metabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), is the most prevalent chronic liver condition worldwide, affecting over 25% of the population. Fatty infiltration in MASLD leads to hemodynamic changes in hepatic circulation, which can be quantitatively assessed using Color Doppler Ultrasonography (US). In this study, we aimed to investigate the correlation of Color Doppler US findings of the portal, hepatic, and splenic venous system within various degrees of MASLD.

METHODS AND MATERIALS

Between 2021 and 2024, 104 patients referred to Mousavi Hospital at Zanjan University of Medical Sciences were enrolled. Participants were divided into four groups based on the degree of hepatic fatty infiltration on biopsy results: normal, grade 1, grade 2, and grade 3, with 26 subjects in each group (13 men and 13 women). All patients were biopsy proved. Gray-scale and Color Doppler US were used to assess portal and splenic vein peak systolic velocity (PSV), portal and splenic vein diameter, hepatic vein waveform, and spleen size. The Spearman rank correlation was employed to evaluate the relationship between these variables under non-parametric conditions.

RESULTS

A significant negative correlation was found between portal vein PSV and MASLD grade (r = - 0.499, p = 0.000). A significant difference was also observed in hepatic venous waveform abnormality between different grades of MASLD (p = 0.043). Accordingly, portal vein PSV and splenic vein PSV had a significantly positive correlation (r = 0.209, p = 0.033). We also observed a positive correlation between the portal vein and splenic diameter (r = 0.210, p = 0.032).

CONCLUSION

Increasing MASLD severity is associated with reduced portal vein PSV and more pronounced abnormalities in hepatic vein flow. Routine assessment of portal and hepatic vein flow using Color Doppler US is recommended to accurately diagnose and monitor the effects of MASLD on hepatic circulation, potentially improving disease management and patient outcomes.

Post-contrast CT liver attenuation alone is superior to the liver-spleen difference for identifying moderate hepatic steatosis

OBJECTIVE

To assess the diagnostic performance of post-contrast CT for predicting moderate hepatic steatosis in an older adult cohort undergoing a uniform CT protocol, utilizing hepatic and splenic attenuation values.

MATERIALS AND METHODS

A total of 1676 adults (mean age, 68.4 ± 10.2 years; 1045M/631F) underwent a CT urothelial protocol that included unenhanced, portal venous, and 10-min delayed phases through the liver and spleen. Automated hepatosplenic segmentation for attenuation values (in HU) was performed using a validated deep-learning tool. Unenhanced liver attenuation < 40.0 HU, corresponding to > 15% MRI-based proton density fat, served as the reference standard for moderate steatosis.

RESULTS

The prevalence of moderate or severe steatosis was 12.9% (216/1676). The diagnostic performance of portal venous liver HU in predicting moderate hepatic steatosis (AUROC = 0.943) was significantly better than the liver-spleen HU difference (AUROC = 0.814) (p < 0.001). Portal venous phase liver thresholds of 80 and 90 HU had a sensitivity/specificity for moderate steatosis of 85.6%/89.6%, and 94.9%/74.7%, respectively, whereas a liver-spleen difference of -40 HU and -10 HU had a sensitivity/specificity of 43.5%/90.0% and 92.1%/52.5%, respectively. Furthermore, livers with moderate-severe steatosis demonstrated significantly less post-contrast enhancement (mean, 35.7 HU vs 47.3 HU; p < 0.001).

CONCLUSION

Moderate steatosis can be reliably diagnosed on standard portal venous phase CT using liver attenuation values alone. Consideration of splenic attenuation appears to add little value. Moderate steatosis not only has intrinsically lower pre-contrast liver attenuation values (< 40 HU), but also enhances less, typically resulting in post-contrast liver attenuation values of 80 HU or less.

CLINICAL RELEVANCE STATEMENT

Moderate steatosis can be reliably diagnosed on post-contrast CT using liver attenuation values alone. Livers with at least moderate steatosis enhance less than those with mild or no steatosis, which combines with the lower intrinsic attenuation to improve detection.

KEY POINTS

The liver-spleen attenuation difference is frequently utilized in routine practice but appears to have performance limitations. The liver-spleen attenuation difference is less effective than liver attenuation for moderate steatosis. Moderate and severe steatosis can be identified on standard portal venous phase CT using liver attenuation alone.

Variation in hepatic segmental portal venous pulsed wave Doppler flow distribution in patients with NAFLD: A pilot study

Purpose

To evaluate the segmental variations in portal venous pulsed wave colour Doppler flow velocity in patients with moderate to severe non-alcoholic fatty liver disease in comparison with healthy controls.

Materials and Methods

In this prospective, observational, case-control study, the maximum velocity of all the segmental branches of portal vein were evaluated on colour Doppler in patients with moderate to severe non-alcoholic fatty liver disease, and the values were compared between three groups (1) Healthy controls (n = 30), (2) non-alcoholic fatty liver disease group, that is moderate to severe fatty liver without features of portal hypertension (n = 32) and (3) non-alcoholic steatohepatitis-portal hypertension group, that is those non-alcoholic fatty liver disease patients with features of portal hypertension (n = 13).

Results

Compared to controls, non-alcoholic fatty liver disease group showed a lower velocity in all the eight segments of liver. The ratio of segment 2 to segment 7 peak portal vein maximum velocity was significantly higher in non-alcoholic fatty liver disease (1.03 ± 0.21) compared to controls (0.90 ± 0.17) and even higher in non-alcoholic steatohepatitis-Portal hypertension group (1.83 ± 0.40) with p value of 0.003.

Conclusion

Our study demonstrates the occurrence of flow redistribution occurring in cases of non-alcoholic fatty liver disease patients with the left lobe receiving higher portal venous flow. This flow redistribution was even more pronounced in a subset of non-alcoholic fatty liver disease patients who developed features of portal hypertension.

Performance of Ultrasound Techniques and the Potential of Artificial Intelligence in the Evaluation of Hepatocellular Carcinoma and Non-Alcoholic Fatty Liver Disease

Global statistics show an increasing percentage of patients that develop non-alcoholic fatty liver disease (NAFLD) and NAFLD-related hepatocellular carcinoma (HCC), even in the absence of cirrhosis. In the present review, we analyzed the diagnostic performance of ultrasonography (US) in the non-invasive evaluation of NAFLD and NAFLD-related HCC, as well as possibilities of optimizing US diagnosis with the help of artificial intelligence (AI) assistance. To date, US is the first-line examination recommended in the screening of patients with clinical suspicion of NAFLD, as it is readily available and leads to a better disease-specific surveillance. However, the conventional US presents limitations that significantly hamper its applicability in quantifying NAFLD and accurately characterizing a given focal liver lesion (FLL). Ultrasound contrast agents (UCAs) are an essential add-on to the conventional B-mode US and to the Doppler US that further empower this method, allowing the evaluation of the enhancement properties and the vascular architecture of FLLs, in comparison to the background parenchyma. The current paper also explores the new universe of AI and the various implications of deep learning algorithms in the evaluation of NAFLD and NAFLD-related HCC through US methods, concluding that it could potentially be a game changer for patient care.

Hemodynamic changes in hepatic sinusoids of hepatic steatosis mice

BACKGROUND

Fatty liver (FL) is now a worldwide disease. For decades, researchers have been kept trying to elucidate the mechanism of FL at the molecular level, but rarely involve the study of morphology and medical physics. Traditionally, it was believed that hemodynamic changes occur only when fibrosis occurs, but it has been proved that these changes already show in steatosis stage, which may help to reveal the pathogenesis and its progress. Because the pseudolobules are not formed during the steatosis stage, this phenomenon may be caused by the compression of the liver microcirculation and changes in the hemodynamics.

AIM

To understand the pathogenesis of hepatic steatosis and to study the hemodynamic changes associated with hepatic steatosis.

METHODS

Eight-week-old male C57BL/6 mice were divided into three groups randomly (control group, 2-wk group, and 4-wk group), with 16 mice per group. A hepatic steatosis model was established by subcutaneous injection of carbon tetrachloride in mice. After establishing the model, liver tissue from mice was stained with hematoxylin and eosin (HE), and oil red O stains. Blood was collected from the angular vein, and hemorheological parameters were estimated. A two-photon fluorescence microscope was used to examine the flow properties of red blood cells in the hepatic sinusoids.

RESULTS

Oil red O staining indicated lipid accumulation in the liver after CCl₄ treatment. HE staining indicated narrowing of the hepatic sinusoidal vessels. No significant difference was observed between the 2-wk and 4-wk groups of mice on morphological examination. Hemorheological tests included whole blood viscosity (mPas, γ = 10 s-¹/γ = 100 s^-1) (8.83 ± 2.22/4.69 ± 1.16, 7.73 ± 2.46/4.22 ± 1.32, and 8.06 ± 2.88/4.22 ± 1.50), red blood cell volume (%) (51.00 ± 4.00, 42.00 ± 5.00, and 40.00 ± 3.00), the content of plasma fibrinase (g/L) (3.80 ± 0.50, 2.90 ± 0.80, and 2.30 ± 0.70), erythrocyte deformation index (%) (44.49 ± 5.81, 48.00 ± 15.29, and 44.36 ± 15.01), erythrocyte electrophoresis rate (mm/s per V/m) (0.55 ± 0.11, 0.50 ± 0.11, and 0.60 ± 0.20), revealing pathological changes in plasma components and red blood cells of hepatic steatosis. Assessment of blood flow velocity in the hepatic sinusoids with a laser Doppler flowmeter (mL/min per 100 g) (94.43 ± 14.64, 80.00 ± 12.12, and 67.26 ± 5.92) and two-photon laser scanning microscope (μm/s) (325.68 ± 112.66, 213.53 ± 65.33, and 173.26 ± 44.02) revealed that as the modeling time increased, the blood flow velocity in the hepatic sinusoids decreased gradually, and the diameter of the hepatic sinusoids became smaller (μm) (10.28 ± 1.40, 6.84 ± 0.93, and 5.82 ± 0.79).

CONCLUSION

The inner diameter of the hepatic sinusoids decreases along with the decrease in the blood flow velocity within the sinusoids and the changes in the systemic hemorheology.

Effects of friction massage of the popliteal fossa on blood flow velocity of the popliteal vein

[Purpose] Friction massage (friction) of the popliteal fossa is provided for the purpose of relieving pain related to circulatory disorders by improving venous flow in the lower legs. The purpose of this study is to verify the effects of enhancing the venous flow based on measuring the blood flow velocity of the popliteal vein before and after providing friction to the patients. [Subjects and Methods] Fifteen healthy male university students participated in the study. The Doppler ultrasonography (DU) was used to measure the blood flow velocity of the popliteal vein, in order to verify the effects of enhancing the venous flow by comparing the measured values before and after a friction massage. [Results] The result of comparing the blood flow velocity before and after providing friction showed that there was a significant increase after friction. [Conclusion] This study proved that friction to the popliteal fossa is effectively enhances venous flow by increasing the blood flow velocity in the popliteal vein.

Assessment of Portal Venous and Hepatic Artery Haemodynamic Variation in Non-Alcoholic Fatty Liver Disease (NAFLD) Patients

INTRODUCTION

Non-Alcoholic Fatty Liver Disease (NAFLD) has various spectrums of liver diseases like isolated fatty liver, steatohepatitis and cirrhosis usually progressing in a linear fashion. In this process they are known to cause certain haemodynamic changes in the portal flow and hepatic artery flow.

AIM

The aim of the study was to study these haemodynamic changes in patients with NAFLD and to correlate it with the disease severity.

MATERIALS AND METHODS

Ninety patients diagnosed to have NAFLD based on ultrasound abdomen (30 each in grade1, grade2 and grade3 NAFLD) and 30 controls (Normal liver on ultrasound abdomen) were subjected to portal vein and hepatic artery Doppler study. Peak maximum velocity (Vmax), Peak minimum velocity (Vmin), Mean flow velocity (MFV), and Vein pulsality index (VPI) of the portal vein and hepatic artery resistivity index (HARI) of the hepatic artery were the doppler parameters which were assessed. Liver span was also assessed both for the fatty liver and controls.

RESULTS

The mean Vmax, Vmin, MFV and VPI of the portal vein in patients with NAFLD was 12.23±1.74cm/sec, 9.31±1.45cm/sec, 10.76±1.48cm/sec, and 0.24±0.04 as compared to 14.05±2.43cm/sec, 10.01±2.27cm/sec, 12.23±2.47cm/sec, 0.3±0.08 in controls respectively. All these differences were statistically significant except for Vmin. The Mean HARI in patients with fatty liver was 0.65±0.06 when compared to controls of 0.75±0.06 (p=0.001). HARI (r-value of -0.517) had a better negative correlation followed by VPI (r-value of -0.44) and Vmax (r-value of -0.293) with the severity of NAFLD. MFV had a very weak negative correlation (r-value of -0.182) with the severity of NAFLD.

CONCLUSION

The Vmax, MFV, VPI and HARI were significantly less when compared to controls suggesting a reduced portal flow and an increased hepatic arterial flow in patients with NAFLD. Among the parameters, HARI correlated better with the severity of NAFLD followed by VPI.

Association of the Nonalcoholic Hepatic Steatosis and Its Degrees With the Values of Liver Enzymes and Homeostasis Model Assessment-Insulin Resistance Index

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is among the most common chronic diseases of the modern world with a wide variety of factors including genetic, environmental and metabolic. The aim of this study was to verify the association between the degrees of hepatic steatosis at the abdominal ultrasound and the values of aminotransferases (aspartate aminotransferase (AST) and alanine transferase (ALT)), gamma glutamyl transpeptidase (GGT) and homeostasis model assessment-insulin resistance (HOMA-IR) index.

METHODS

A prospective, descriptive survey study, using a quantitative analytical examination, was conducted from July 2013 to July 2014. In the statistical analysis, values were expressed as median, first and third quartiles. We used the nonparametric Kruskal-Wallis test to compare the medians between the degrees of steatosis, adopted a statistical significance of 5% (P ≤ 0.05) and used the statistical program SPSS 22.0.

RESULTS

We diagnosed 233/800 (29.1%) patients with hepatic steatosis on routine ultrasound, and 65.7% were female. Regarding degrees, 119 had grade 1 (51.0%), 94 grade 2 (40.4%) and 20 grade 3 (8.6%). The median age of the patients with grade 1, 2 or 3 did not vary significantly (P > 0.05). The median body mass index (BMI), although clinically important because of its elevation, did not differ significantly (P > 0.05). ALT levels increased as the degree of hepatic steatosis has advanced as well as the levels of AST, GGT and HOMA-IR. AST values showed a greater association with the severity of fatty liver (P = 0.0001) than the ALT (P = 0.001).

CONCLUSIONS

ALT, AST, GGT and HOMA-IR are associated to the degrees of hepatic steatosis on ultrasound and can help in the selection of patients for the liver histological evaluation.