The utility of Xenon-133 liver scan in the diagnosis and management of nonalcoholic fatty liver disease

Enhanced non-alcoholic fatty liver detection: Computed tomography scan image analysis and noise reduction with morphological dilation

Non-alcoholic fatty liver disease (NAFLD) is characterized by accumulation of fat in the liver cells caused by means other than alcohol consumption. It is one of the most common chronic liver diseases worldwide and can lead to severe conditions, such as cirrhosis and liver cancer. NAFLD is often associated with other metabolic disorders, such as obesity and diabetes, and is closely related to lifestyle factors, such as diet and physical activity [1]. The diagnosis as well as management of NAFLD are complex and involve a multidisciplinary approach. The available treatment options include lifestyle modifications, pharmacological interventions, and in severe cases, liver transplantation. The increasing prevalence of NAFLD highlights the urgent requirement of effective prevention and management strategies. This disease is a growing health concern in India, given the rise in the incidence of obesity and diabetes. According to a study published in the Journal of Clinical and Experimental Hepatology in 2020, the prevalence of NAFLD in India is estimated to be between 9% and 32%. In accordance with the research population and diagnostic criteria employed, a study published in the Indian Journal of Gastroenterology in 2019 found that the prevalence of NAFLD in India ranged from 9.6% to 32.3% [2]. The same study also revealed that the prevalence of non-alcoholic steatohepatitis (NASH), a highly severe form of NAFLD, ranged from 1.5% to 8.4%. These statistics highlight the need for increased awareness and preventive measures to manage the growing burden of NAFLD in India.

Recent advances in non-invasive diagnosis and medical management of non-alcoholic fatty liver disease in adult

Background

Number of non-alcoholic fatty liver disease (NAFLD) cases is increasing over time due to alteration of food habit, increase incidence of metabolic syndrome, and lack of exercise. Liver biopsy is the test for diagnosis and staging of NAFLD, but nowadays several biochemical markers, scoring systems, and imaging studies are available to diagnose and stage NAFLD which is linked to end-stage liver disease, hepatocellular cancer, and elevated cardiovascular- and cancer-related morbidity and mortality. Therefore urgent diagnosis and management are required to avoid complications related to NAFLD. This review summarizes recent advances in diagnosis and medical management of non-alcoholic fatty liver disease.

Main text

Recently published studies from PubMed, Red Cross, Copernicus, and also various previous studies were reviewed. We have discussed various non-invasive methods for detection of non-alcoholic fatty liver disease, non-alcoholic steatohepatitis (NASH), and hepatic fibrosis. Non pharmacological therapies for NAFLD, indications, and approved medications for NAFLD and other commonly used non-approved medications have been discussed in this review article.

Conclusions

Multiple non-invasive tests are available for diagnosis of NAFLD, and its different stages however gold standard test is liver biopsy. NALFD without NASH and significant fibrosis is treated by lifestyle modifications which include moderate to vigorous exercise and diet modification. To improve hepatic steatosis, minimum of 3–5% of body weight loss is necessary, but > 7–10% weight reductions is required for histological improvement in NASH and fibrosis. Pharmacotherapy is indicated when patient is having NASH with significant fibrosis.

Non-Invasive Assessment Method Using Thoracic-Abdominal Profile Image Acquisition and Mathematical Modeling with Bezier Curves

The study was performed at Brasov County Hospital, in the Internal Medicine, Diabetes, Gastroenterology and Cardiology Wards with the collaboration of Transylvania University of Brasov, as a study approved by the Ethical Board of the university. The study aimed at assessing the connection between the anthropometric parameters of abdominal adiposity (measured by means of an original experiment designed to determine the curvature of the thoracic-abdominal adiposity for the patients and processed by help of a mathematical model based upon Bezier curves geometry) and the fat load of the liver (assessed by ultrasound by measuring the diameters of both hepatic lobes) for the patients diagnosed with Non-Alcoholic Fatty Liver Disease (NAFLD). The existence of ten types of thoracic-abdominal curves profiles were statistically analyzed in order to evaluate in a simple manner the liver size in NAFLD. The method of diagnosis is based on an easily reproduced experiment, it is original, innovative, non-invasive, and cost-effective. Can be implemented anywhere in the world, there is no need for investment, only for determining the profile of the belly.

Non-alcoholic fatty liver disease--a chronic disease of the 21^st century

Non-alcoholic fatty liver disease (NAFLD) comprises a spectrum of metabolic states ranging from simple steatosis to inflammation with associated fibrosis to cirrhosis. Though accumulation of hepatic fat is not associated with a significant increase in mortality rates, hepatic inflammation is, as this augments the risk of terminal liver disease, i.e., cirrhosis, hepatic decompensation (liver failure) and/or hepatocellular carcinoma. Disease progression is usually slow, over a decade or more and, for the most part, remains asymptomatic. Recent estimates suggest that the global prevalence of NAFLD is high, about one in four. In most cases, NAFLD overlaps with overweight, obesity, cardiovascular disease and the metabolic syndrome with numerous contributing parameters including a dysregulation of adipose tissue, insulin resistance, type 2 diabetes, changes in the gut microbiome, neuronal and hormonal dysregulation and metabolic stress. NAFLD is diagnosed incidentally, despite its high prevalence. Non-invasive imaging techniques have emerged, making it possible to determine degree of steatosis as well asfibrosis. Despite this, the benefit of routine diagnostics remains uncertain. A better understanding of the (molecular) pathogenesis of NAFLD is needed combined with long-term studies where benefits of treatment can be assessed to determine cost-benefit ratios. This review summarizes the current state of knowledge and possible areas of treatment.

Prognostic Value of Non-Invasive Fibrosis and Steatosis Tools, Hepatic Venous Pressure Gradient (HVPG) and Histology in Nonalcoholic Steatohepatitis

Background & Aims

Non-invasive diagnostic methods for liver fibrosis predict clinical outcomes in viral hepatitis and nonalcoholic fatty liver disease (NAFLD). We specifically evaluated prognostic value of non-invasive fibrosis methods in nonalcoholic steatohepatitis (NASH) against hepatic venous pressure gradient (HVPG) and liver histology.

Methods

This was a retrospective cohort study of 148 consecutive patients who met the following criteria: transjugular liver biopsy with HVPG measurement; biopsy-proven NASH; absence of decompensation; AST-to-Platelets Ratio Index (APRI), fibrosis-4 (FIB-4), NAFLD fibrosis score, ultrasound, hepatic steatosis index and Xenon-133 scan available within 6 months from biopsy; a minimum follow-up of 1 year. Outcomes were defined by death, liver transplantation, cirrhosis complications. Kaplan–Meier and Cox regression analyses were employed to estimate incidence and predictors of outcomes, respectively. Prognostic value was expressed as area under the curve (AUC).

Results

During a median follow-up of 5 years (interquartile range 3-8), 16.2% developed outcomes, including 7.4% who died or underwent liver transplantation. After adjustment for age, sex, diabetes, the following fibrosis tools predicted outcomes: HVPG >10mmHg (HR=9.60; 95% confidence interval [CI] 3.07-30.12), histologic fibrosis F3-F4 (HR=3.14; 1.41-6.95), APRI >1.5 (HR=5.02; 1.6-15.7), FIB-4 >3.25 (HR=6.33; 1.98-20.2), NAFLD fibrosis score >0.676 (HR=11.9; 3.79-37.4). Prognostic value was as follows: histologic fibrosis stage, AUC=0.85 (95% CI 0.76-0.93); HVPG, AUC=0.81 (0.70-0.91); APRI, AUC=0.89 (0.82-0.96); FIB-4, AUC=0.89 (0.83-0.95); NAFLD fibrosis score, AUC=0.79 (0.69-0.91). Neither histologic steatosis nor non-invasive steatosis methods predicted outcomes (AUC<0.50).

Conclusions

Non-invasive methods for liver fibrosis predict outcomes of patients with NASH. They could be used for serial monitoring, risk stratification and targeted interventions.

Nonalcoholic fatty liver disease: Noninvasive methods of diagnosing hepatic steatosis

Hepatic steatosis is the buildup of lipids within hepatocytes. It is the simplest stage in nonalcoholic fatty liver disease (NAFLD). It occurs in approximately 30% of the general population and as much as 90% of the obese population in the United States. It may progress to nonalcoholic steatohepatitis, which is a state of hepatocellular inflammation and damage in response to the accumulated fat. Liver biopsy remains the gold standard tool to diagnose and stage NAFLD. However, it comes with the risk of complications ranging from simple pain to life-threatening bleeding. It is also associated with sampling error. For these reasons, a variety of noninvasive radiological markers, including ultrasound, computed tomography, magnetic resonance spectroscopy, and the controlled attenuation parameter using transient elastography and Xenon-133 scan have been proposed to increase our ability to diagnose NAFLD, hence avoiding liver biopsy. The aim of this review is to discuss the utility and accuracy of using available noninvasive diagnostic modalities for fatty liver in NAFLD.