Role of Diffusion-Weighted Magnetic Resonance Imaging in the Diagnosis and Grading of Hepatic Steatosis in Patients With Non-alcoholic Fatty Liver Disease: Comparison With Ultrasonography and Magnetic Resonance Spectroscopy

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is becoming the most common cause of cirrhosis. Although magnetic resonance spectroscopy (MRS) is considered the gold standard, it has a few limitations. The role of diffusion-weighted imaging (DWI), which is a simpler sequence, in the diagnosis and grading of fatty liver is not well studied. The aim of the study was to investigate the value of DWI in the diagnosis and grading of hepatic steatosis in patients with NAFLD.

MATERIALS AND METHODS

Fifty-one adults (mean age: 38 years; 28 men, 23 women) with NAFLD, diagnosed clinically and by ultrasonography (USG), were included in the study after obtaining informed consent and approval from the institute ethics committee. USG was performed for grading of hepatic steatosis in all patients, followed by magnetic resonance imaging with DWI and MRS, on a 1.5T scanner. The mean apparent diffusion coefficient (ADC) values and proton density fat fraction (PDFF) were calculated, and MRS was used as the gold standard. The mean ADC values were compared with the PDFF and USG grades.

RESULTS

There was a weak correlation between ADC values and PDFF (r = -0.36; P < 0.05). In addition, there was a weak correlation between the ADC values of the liver and USG grade (r = -0.34; P < 0.05). However, an overall increase in USG grades and PDFF was associated with decrease in the mean ADC value (P < 0.001).

CONCLUSION

DWI is not accurate in the diagnosis and grading of hepatic steatosis in patients with NAFLD. However, a significant increase in fat deposition in the liver lowers the ADC values.

Role of Magnetic Resonance Imaging in the Monitoring of Patients with Nonalcoholic Fatty Liver Disease: Comparison with Ultrasonography, Lipid Profile, and Body Mass Index

AIM

The aim of this study was to study the role of magnetic resonance imaging (MRI) in monitoring hepatic fat content in cases of nonalcoholic fatty liver disease (NAFLD).

MATERIALS AND METHODS

41 adults (mean age: 39 years, 22 males; 19 females) with NAFLD were included after obtaining approval from the institutional ethics committee. The baseline clinical (weight, body mass index [BMI]) and biochemical parameters, fatty liver grade on ultrasonography (USG), and hepatic fat signal fraction (FSF) using dual-echo chemical shift imaging and proton density fat fraction on magnetic resonance spectroscopy (MRS-PDFF) were assessed, before and after intervention (dietary and lifestyle changes and oral vitamin E for six months). They were categorized into Group A (good compliance to intervention) and Group B (poor compliance), and the clinical and imaging parameters were compared between them.

RESULTS

After intervention, Group A (n = 30) showed significant reduction in BMI (28.35 ± 3.25 to 27.14 ± 3.24 kg/m²; P < 0.001), hepatic FSF (19.30 ± 9.09% to 11.18 ± 7.61%; P < 0.05), and MRS-PDFF (18.79 ± 8.53% to 10.64 ± 6.66%). In Group B (n = 11), there was significant increase in BMI (28.85 ± 2.41 to 29.31 ± 2.57 kg/m²; P < 0.001), hepatic FSF (18.96 ± 9.79% to 21.48 ± 11.80%; P < 0.05), and reduction in high-density lipoproteins (P < 0.05). Although there was good correlation between USG and MRS in quantifying liver fat (r = 0.84-0.87; P < 0.001), USG was unable to detect <5.3% change in hepatic fat. There was poor correlation between lipid profile and MRS-PDFF. Change in body weight significantly correlated with change in hepatic fat content (r = 0.76; P < 0.001).

CONCLUSION

MRI is useful in accurately quantifying and in monitoring hepatic fat content and is better than clinical and biochemical parameters and USG.

Drug Development for Nonalcoholic Fatty Liver Disease: Landscape and Challenges

Nonalcoholic fatty liver disease (NAFLD) is now the leading cause of chronic liver disease in industrialized economies. With no licensed treatment currently available, together with a growing prevalence that parallels global increases in obesity and type 2 diabetes, NAFLD will dominate the landscape of hepatology for the foreseeable future. A multifaceted etiopathogenesis, paucity of reproducible preclinical models that effectively recreate human NAFLD, and lack of robust surrogate trial endpoints have presented major hurdles in drug discovery and development. Smooth collaboration between bench scientists, biotechnology, pharmaceutical industries, and clinicians will be pivotal to target identification, development of effective therapies, biomarker discovery, and ultimately to bring pipeline drugs to market. This review examines the key challenges remaining in NAFLD drug development, outlines early and late phase clinical trials of candidate treatments, and discusses the journey toward biomarker discovery which may facilitate development of novel endpoints in NAFLD clinical trials, enabling meaningful response to be determined noninvasively.