Controlled attenuation parameter using the FibroScan® XL probe for quantification of hepatic steatosis for non-alcoholic fatty liver disease in an Asian population

Liver Ultrasound Elastography: An Update to the World Federation for Ultrasound in Medicine and Biology Guidelines and Recommendations

The World Federation for Ultrasound in Medicine and Biology has produced these guidelines for the use of elastography techniques in liver diseases. For each available technique, the reproducibility, results and limitations are analyzed, and recommendations are given. This set of guidelines updates the first version, published in 2015. Since the prior guidelines, there have been several advances in technology. The recommendations are based on the international published literature, and the strength of each recommendation is judged according to the Oxford Centre for Evidence-Based Medicine. The document has a clinical perspective and is aimed at assessing the usefulness of elastography in the management of liver diseases.

Quantitative Hepatic Fat Quantification in Non-alcoholic Fatty Liver Disease Using Ultrasound-Based Techniques: A Review of Literature and Their Diagnostic Performance

Non-alcoholic fatty liver disease is a condition that is characterized by the presence of >5% fat in the liver and affects more than one billion people worldwide. If adequate and early precautions are not taken, non-alcoholic fatty liver disease can progress to cirrhosis and death. The current reference standard for detecting hepatic steatosis is a liver biopsy. However, because of the potential morbidity associated with liver biopsies, non-invasive imaging biomarkers have been extensively investigated. Magnetic resonance imaging-based methods have proven accuracy in quantifying liver steatosis; however, these techniques are costly and have limited availability. Ultrasound-based quantitative imaging techniques are increasingly utilized because of their widespread availability, ease of use and relative cost-effectiveness. Several ultrasound-based liver fat quantification techniques have been investigated, including techniques that measure changes in the acoustic properties of the liver caused by the presence of fat. In this review, we focus on quantitative ultrasound approaches and their diagnostic performance in the realm of non-alcoholic fatty liver disease.

Can the same controlled attenuation parameter cut-offs be used for M and XL probes for diagnosing hepatic steatosis?

BACKGROUND AND AIM

There are limited studies on controlled attenuation parameter (CAP) using Fibroscan XL probe for the diagnosis of hepatic steatosis grade. The aim of this study was to determine whether previously defined optimal cut-offs for CAP using the M probe could be applied for the XL probe.

METHODS

Adult patients with chronic liver disease who had a liver biopsy and examination with both the M and XL probes were included. Previously defined optimal cut-offs for CAP using the M probe were used for the diagnosis of steatosis grades ≥S1, ≥S2, and S3 (248, 268, and 280 dB/m, respectively).

RESULTS

Data for 180 patients were analyzed (mean age 53.7 ± 10.8 years; central obesity 84.5%; non-alcoholic fatty liver disease 86.7%). The distribution of steatosis grades was S0, 9.4%; S1, 28.3%; S2, 43.9%, and S3, 18.3%. The sensitivity, specificity, positive predictive value, and negative predictive value of CAP using the M/XL probe for the diagnosis of steatosis grade ≥S1 was 93.9%/93.3%, 58.8%/58.8%, 95.6%/95.6%, and 50.0%/47.6%, respectively. These values were 94.6%/94.6%, 41.2%/44.1%, 72.6%/73.6%, and 82.4%/83.3%, respectively, for ≥S2, and 87.9%/87.9%, 27.2%/27.9%, 21.3%/21.5%, and 90.9%/91.1%, respectively, for S3.

CONCLUSION

The same cut-off values for CAP may be used for the M and XL probes for the diagnosis of hepatic steatosis grade.

Optimal threshold of controlled attenuation parameter with MRI-PDFF as the gold standard for the detection of hepatic steatosis

The optimal threshold of controlled attenuation parameter (CAP) for the detection of hepatic steatosis using both M and XL probe is unknown in nonalcoholic fatty liver disease (NAFLD). Magnetic resonance imaging proton density fat fraction (MRI-PDFF) is an accurate and precise method of detecting the presence of hepatic steatosis that is superior to CAP. Thus, the aim of this study was to evaluate the diagnostic accuracy and optimal threshold of CAP for the detection of hepatic steatosis as defined by MRI-PDFF ≥ 5%. This prospective cross-sectional study included 119 adults (59% women) with and without NAFLD who underwent MRI-PDFF and CAP using either M or XL probe when indicated within a 6-month period at the NAFLD Research Center, University of California, San Diego. The mean ( ± standard deviation) age and body mass index were 52.4 (±15.2) years and 29.9 (±5.5) kg/m2 , respectively. The prevalence of NAFLD (MRI-PDFF ≥ 5%) and MRI-PDFF ≥ 10% was 70.6% and 47.1%, respectively. The area under the receiver operating characteristic (AUROC) of CAP for the detection of MRI-PDFF ≥ 5% was 0.80 (95% confidence interval [CI], 0.70-0.90) at the cut-point of 288 dB/m and of MRI-PDFF ≥ 10% was 0.87 (95% CI, 0.80-0.94) at the cut-point of 306 dB/m. When stratified by the interquartile range (IQR) of CAP, we observed that an IQR below the median (30 dB/m) had a robust AUROC compared with an IQR above the median (0.92 [95% CI, 0.85-1.00] versus 0.70 [95% CI, 0.56-0.85]; P = 0.0117), and these differences were statistically and clinically significant.

CONCLUSION

The cut-point of CAP for presence of hepatic steatosis (MRI-PDFF ≥ 5%) was 288 dB/m. The diagnostic accuracy of CAP for the detection of hepatic steatosis is more reliable when the IQR of CAP is <30 dB/m. These data have implications for the clinical use of CAP in the assessment of NAFLD. (Hepatology 2018;67:1348-1359).

Role of imaging-based biomarkers in NAFLD: Recent advances in clinical application and future research directions

Non-alcoholic fatty liver disease (NAFLD) is a major public health problem afflicting approximately one billion individuals worldwide. Liver biopsy is considered the gold standard for assessment of liver disease severity in patients with NAFLD. However, it is invasive, has high inter-observer variability, and is associated with adverse effects, including pain, infection and, albeit rarely, death. It is also impractical because of the large number of individuals who have NAFLD. Therefore, tools to non-invasively assess disease severity in NAFLD are urgently needed. Over the last two decades, tremendous advances have been made in the assessment of NAFLD by non-invasive imaging. In this review, we will discuss the different non-invasive imaging modalities available to quantify liver fat and liver fibrosis. We will also discuss the limitations of current modalities to detect the progressive form for NAFLD, termed non-alcoholic steatohepatitis. Finally, we will discuss the comparative efficacy of various imaging-based elastographic modalities for detection of advanced fibrosis or cirrhosis, as well as their diagnostic characteristics.

Changes in inflammatory factors and prognosis of patients complicated with non-alcoholic fatty liver disease undergoing coronary artery bypass grafting

This study was designed to assess the relationship between changes in peripheral inflammatory factors of patients complicated with non-alcoholic fatty liver disease (NAFLD) undergoing coronary artery bypass grafting (CABG) before and after operation, and their prognosis. A total of 68 patients with stable angina pectoris treated in Xinjiang Hospital who underwent CABG at some point between August of 2013 and August of 2015 were enrolled in the study, and divided into the NAFLD group (n=31) and the non-NAFLD group (n=37) according to the presence of the condition or its absence. Peripheral blood was drawn from the patients before and at 24 h and 1 month after the operation, and the expression levels of high-sensitivity C-reactive protein (hsCRP), soluble CD40 ligand (sCD40L), intercellular adhesion molecule-1 (ICAM-1) and matrix metalloproteinase-9 (MMP-9) were measured via standard enzyme-linked immunosorbent assay. Our results showed the expression levels of hsCRP and sCD40L of patients in both groups reached a peak 24 h after operation; and there were statistically significant changes compared with the levels before the operation and at 1 month after operation (p<0.01). However, there were no statistically significant differences in the expression levels between the two groups (p>0.05). The expression levels of ICAM-1 at each time-point in both groups were increased after the operation, but the changes were not statistically significant (p>0.05). The expression levels of MMP-9 increased after the operation, and the levels at 1 month after operation were significantly higher than those before operation and at 24 h after the operation (p<0.01). Importantly, the expression levels of MMP-9 of patients in the NAFLD group at 1 month after operation were significantly higher than those of patients in the non-NAFLD group at the same time, and the differences were statistically significant (p<0.01). Finally, logistic regression analysis showed that the expression level of MMP-9 was an important influencing factor for cardiovascular events after CABG (OR=1.182, p<0.05). Based on our findings, the expression levels of inflammatory factors in peripheral blood in patients complicated with NAFLD undergoing CABG differ from those who are not complicated, and the MMP-9 levels may be closely related to the prognosis of patients complicated with NAFLD.