Diagnostic Accuracy and Optimal Cut-off of Controlled Attenuation Parameter for the Detection of Hepatic Steatosis in Indian Population

Evaluation of Controlled Attenuation Parameter as a Tool for Assessment of Hepatic Steatosis in Living Liver Donors

Background

Currently, there is an absence of a standardised protocol for the preoperative detection of hepatic steatosis (HS) in living liver donors. A steatotic liver graft jeopardises the outcome of the recipient with multiple potential complications. Vibration-controlled transient elastography (Fibroscan®) provides a controlled attenuation parameter (CAP), which we have utilised in our assessment of HS in living liver donors. This approach offers a promising avenue for the advancement of preoperative evaluation protocols.

Methods

In the period spanning from October 2022 to July 2024, a cohort of 67 liver donors were subjected to preoperative vibration-controlled transient elastography (Fibroscan®) and either preoperative or intraoperative liver biopsy. HS was defined as a fat content exceeding 10%. CAP readings were juxtaposed with liver biopsy results for the diagnosis of HS. Donors were categorised into three categories with HS <5%, 5-10% and those with HS >10% were rejected as per our institutional protocol. This facilitated a comprehensive evaluation of HS in the context of living donor liver transplantation.

Results

CAP was very accurate in detecting HS, with an area under the receiver operating characteristic curve of 0.99 (P < 0.05). Statistical analysis determined that a CAP cutoff value of 266 dB/m provides a sensitivity of 100% and a specificity of 98.4% for predicting HS >10%. Corresponding positive predictive value (PPV) is 85.71%, while the negative predictive value is 100%. Univariate analysis determined body mass index (BMI), age and serum triglyceride levels were associated with CAP; however, multivariate linear regression revealed an association with only BMI (P < 0.001) and age (P < 0.002). When a lower fat threshold of 5% was considered to define HS with the same cut off of CAP, the sensitivity reduced to 66.7% and specificity was 98.3% The recipients of donors with HS of 5%-10% did not show any negative outcomes.

Conclusion

CAP demonstrates significant potential as a predictive tool for hepatic steatosis (HS) in living liver donors. Notably, BMI and age have been identified as independent factors associated with CAP values.

Accuracy of Controlled Attenuation Parameter for Liver Steatosis in High-Risk Patients for MASLD Using MRI-Proton Density Fat Fraction as Reference Standard

AIM

Controlled attenuation parameter (CAP) enables the noninvasive diagnosis of liver steatosis. Magnetic resonance imaging proton density fat fraction (MRI-PDFF) is increasingly used over biopsy for the assessment of steatosis in patients at risk for metabolic dysfunction-associated steatotic liver disease (MASLD). We assessed the accuracy of CAP for liver steatosis defined as MRI-PDFF ≥ 5%.

METHODS

We performed a cross-sectional, diagnostic accuracy study. We prospectively recruited consecutive adult participants with type 2 diabetes and body mass index (BMI) ≥ 25 kg/m2, who underwent CAP and MRI-PDFF within two weeks.

RESULTS

We included 113 participants. The area under the receiver operating characteristic (AUROC) of CAP for MRI-PDFF ≥ 5% was 0.82 [95% confidence interval (CI) 0.74-0.89]. CAP thresholds for ruling-out (sensitivity > 90%) and ruling-in (specificity > 90%) liver steatosis were below 249 and over 328 dB/m respectively. The AUROC of CAP for the detection of MRI-PDFF ≥ 10% was 0.81 (0.73-0.88). CAP thresholds for ruling-out and ruling-in MRI-PDFF ≥ 10% were below 271 and over 345 dB/m respectively. CAP measurements with an interquartile range (IQR) < 30 dB/m improved the detection of higher steatosis grades.

CONCLUSION

CAP has acceptable accuracy for diagnosing MRI-PDFF defined steatosis. Values below 249 dB/m can be used to rule-out liver steatosis, while values over 328 dB/m can set the diagnosis. An IQR < 30 dB/m might improve the accuracy of CAP for higher steatosis grades.

CLINICAL TRIAL REGISTRATION

Not applicable.

Accuracy of controlled attenuation parameter for liver steatosis in patients at risk for metabolic dysfunction-associated steatotic liver disease using magnetic resonance imaging: a systematic review and meta-analysis

Background

The controlled attenuation parameter (CAP) enables the noninvasive assessment of liver steatosis. We performed a systematic review and meta-analysis to evaluate the diagnostic accuracy of CAP for identifying liver steatosis in patients at risk for metabolic dysfunction-associated steatotic liver disease (MASLD), using magnetic resonance imaging proton density fat fraction (MRI-PDFF) as the reference standard.

Methods

We searched Medline, Embase, Cochrane Library and gray literature sources up to March 2024. We defined MASLD as MRI-PDFF ≥5%. We also assessed the accuracy of CAP for identifying patients with MRI-PDFF ≥10%. We calculated pooled sensitivity and specificity estimates using hierarchical random-effects models. We assessed the risk of bias using the Quality Assessment of Diagnostic Accuracy Studies 2 tool, and the certainty in meta-analysis estimates using the Grading of Recommendations Assessment, Development and Evaluation framework.

Results

We included 8 studies with 1116 participants. The prevalence of MASLD ranged from 65.2-93.9%. Pooled sensitivity and specificity of CAP for MRI-PDFF ≥5% were 0.84 (95% confidence interval [CI] 0.79-0.88) and 0.77 (95%CI 0.68-0.84), respectively, with an area under the receiver operating characteristic curve (AUROC) of 0.88. The pooled sensitivity and specificity for MRI-PDFF ≥10% were 0.83 (95%CI 0.80-0.87) and 0.72 (95%CI 0.59-0.82), with an AUROC of 0.85. The certainty in our estimates was low to very low because of the high risk of bias, inconsistency and imprecision.

Conclusions

CAP has acceptable diagnostic accuracy for both MRI-PDFF ≥5% and MRI-PDFF ≥10%. Adequately powered and rigorously conducted diagnostic accuracy studies are warranted to establish the optimal CAP thresholds.

A Novel Score Based on Controlled Attenuation Parameter Accurately Predicts Hepatic Steatosis in Individuals With Metabolic Dysfunction Associated Steatotic Liver Disease: A Derivation and Independent Validation Study

INTRODUCTION

In metabolic dysfunction-associated steatotic liver disease, the diagnostic efficacy of controlled attenuation parameter (CAP) was not very accurate in evaluating liver fat content. The aim of this study was to develop a score, based on CAP and conventional clinical parameters, to improve the diagnostic performance of CAP regarding liver fat content.

METHODS

A total of 373 participants from 2 independent Chinese cohorts were included and divided into derivation (n = 191), internal validation (n = 75), and external validation (n = 107) cohorts. Based on the significant difference index between the 2 groups defined by the magnetic resonance imaging-proton density fat fraction (MRI-PDFF) in derivation cohort, the optimal model (CAP-BMI-AST score [CBST]) was screened by the number of parameters and the area under the receiver operating characteristic curve (AUROC). In the internal and external validation cohorts, the AUROC and corresponding 95% confidence intervals (CIs) were used to compare the diagnostic performance of CBST with that of CAP.

RESULTS

We constructed the CBST = -14.27962 + 0.05431 × CAP - 0.14266 × body mass index + 0.01715 × aspartate aminotransferase. When MRI-PDFF was ≥20%, ≥10%, and ≥5%, the AUROC for CBST was 0.77 (95% CI 0.70-0.83), 0.89 (95% CI 0.83-0.94), and 0.93 (95% CI 0.88-0.98), which was higher than that for CAP respectively. In the internal validation cohort, the AUROC for CBST was 0.80 (95% CI 0.70-0.90), 0.95 (95% CI 0.91-1.00), and 0.98 (95% CI 0.94-1.00). The optimal thresholds of CBST were -0.5345, -1.7404, and -1.9959 for detecting MRI-PDFF ≥20%, ≥10%, and ≥5%, respectively.

DISCUSSION

The CBST score can accurately evaluate liver steatosis and is superior to the CAP.

Non-invasive hepatic fat quantification: Can multi-echo Dixon help?

Objective

To evaluate the diagnostic accuracy of multi-echo Dixon magnetic resonance imaging (MRI) in hepatic fat quantification, in comparison with that of magnetic resonance spectroscopy (MRS), on 3.0-T MRI.

Materials and Methods

Fifty-five adults with no known liver disease underwent MRI in a 3.0-T scanner for determination of the hepatic fat fraction, with two techniques: multi-echo Dixon, in a manually drawn region of interest (ROI) and in the entire liver parenchyma (automated segmentation); and MRS. The diagnostic accuracy and cutoff value for multi-echo Dixon were determined, with MRS being used as the reference standard.

Results

The mean fat fraction obtained by multi-echo Dixon in the manually drawn ROI and in the entire liver was 5.2 ± 5.8% and 6.6 ± 5.2%, respectively, whereas the mean hepatic fat fraction obtained by MRS was 5.7 ± 6.4%. A very strong positive correlation and good agreement were observed between MRS and multi-echo Dixon, for the ROI (r = 0.988, r2 = 0.978, p < 0.001) and for the entire liver parenchyma (r = 0.960, r2 = 0.922, p < 0.001). A moderate positive correlation was observed between the hepatic fat fraction and body mass index of the participants, regardless of the fat estimation technique employed.

Conclusion

For hepatic fat quantification, multi-echo Dixon MRI demonstrated a very strong positive correlation and good agreement with MRS (often considered the gold-standard noninvasive technique). Because multi-echo Dixon MRI is more readily available than is MRS, it can be used as a rapid tool for hepatic fat quantification, especially when the hepatic fat distribution is not homogeneous.

First-in-human diagnostic study of hepatic steatosis with computed ultrasound tomography in echo mode

BACKGROUND

Non-alcoholic fatty liver disease is rapidly emerging as the leading global cause of chronic liver disease. Efficient disease management requires low-cost, non-invasive techniques for diagnosing hepatic steatosis accurately. Here, we propose quantifying liver speed of sound (SoS) with computed ultrasound tomography in echo mode (CUTE), a recently developed ultrasound imaging modality adapted to clinical pulse-echo systems. CUTE reconstructs the spatial distribution of SoS by measuring local echo phase shifts when probing tissue at varying steering angles in transmission and reception.

METHODS

In this first-in-human phase II diagnostic study, we evaluated the liver of 22 healthy volunteers and 22 steatotic patients. We used conventional B-mode ultrasound images and controlled attenuation parameter (CAP) to diagnose the presence (CAP≥ 280 dB/m) or absence (CAP < 248 dB/m) of steatosis in the liver. A fully integrated convex-probe CUTE implementation was developed on the ultrasound system to estimate liver SoS. We investigated its diagnostic value via the receiver operating characteristic (ROC) analysis and correlation to CAP measurements.

RESULTS

We show that liver CUTE-SoS estimates correlate strongly (r = -0.84, p = 8.27 × 10-13) with CAP values and have 90.9% (95% confidence interval: 84-100%) sensitivity and 95.5% (81-100%) specificity for differentiating between normal and steatotic livers (area under the ROC curve: 0.93-1.0).

CONCLUSIONS

Our results demonstrate that liver CUTE-SoS is a promising quantitative biomarker for diagnosing liver steatosis. This is a necessary first step towards establishing CUTE as a new quantitative add-on to diagnostic ultrasound that can potentially be as versatile as conventional ultrasound imaging.

Indian National Association for Study of the Liver (INASL) Guidance Paper on Nomenclature, Diagnosis and Treatment of Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) is a major cause of chronic liver disease globally and in India. The already high burden of NAFLD in India is expected to further increase in the future in parallel with the ongoing epidemics of obesity and type 2 diabetes mellitus. Given the high prevalence of NAFLD in the community, it is crucial to identify those at risk of progressive liver disease to streamline referral and guide proper management. Existing guidelines on NAFLD by various international societies fail to capture the entire landscape of NAFLD in India and are often difficult to incorporate in clinical practice due to fundamental differences in sociocultural aspects and health infrastructure available in India. A lot of progress has been made in the field of NAFLD in the 7 years since the initial position paper by the Indian National Association for the Study of Liver on NAFLD in 2015. Further, the ongoing debate on the nomenclature of NAFLD is creating undue confusion among clinical practitioners. The ensuing comprehensive review provides consensus-based, guidance statements on the nomenclature, diagnosis, and treatment of NAFLD that are practically implementable in the Indian setting.

Liver Stiffness Values in Persons with Normal Histology

Background and aims

Most studies to date have focused on liver stiffness measurement (LSM) in patients with different chronic liver diseases, and normal LSM is defined based on normal liver function tests or the absence of fibrosis. Very few studies have defined LSM based on completely normal liver biopsies. The current study was done to define the distribution of LSM values in individuals with normal liver biopsies.

Methods

All prospective liver donors presenting to Medanta, the Medicity hospital between September 2020 and September 2021 fulfilling the eligibility criteria were included in this study.

Results

A total of 63 donors (36 females and 27 males) were included in the study, 37 (58.7%) donors had normal liver biopsies, and 26 (41.2%) donors showed the presence of non-alcoholic fatty liver disease. LSM values in the normal liver histology group were 5.01 ± 1.99 kPa by the M probe and 5.34 ± 2.25 kPa by the XL probe. Even though the correlation was weak (r = 0.29, P = 0.03), M probe LSM correlated positively with body mass index. There was a good correlation between the LSM measured by the M probe and the XL probe (r = 0.73, P = <0.001).

Conclusions

LSM value in the biopsy-proven normal liver histology group was 5.01 ± 1.99 by the M probe and 5.34 ± 2.25 by the XL probe.

Ultrasound-Based Diagnostic Methods: Possible Use in Fatty Liver Disease Area

Liver steatosis is a chronic liver disease that is becoming one of the most important global health problems, due to its direct connection with metabolic syndrome, its significant impact on patients' socioeconomic status and frailty, and the occurrence of advanced chronic liver disease. In recent years, there has been rapid technological progress in the ultrasound-based diagnostics field that can help us to quantitatively assess liver steatosis, including continuous attenuation parameters in A and B ultrasound modes, backscatter coefficients (e.g., speed of sound) and ultrasound envelope statistic parametric imaging. The methods used in this field are widely available, have favorable time and financial profiles, and are well accepted by patients. Less is known about their reliability in defining the presence and degree of liver steatosis. Numerous study reports have shown the methods' favorable negative and positive predictive values in comparison with reference investigations (liver biopsy and MRI). Important research has also evaluated the role of these methods in diagnosing and monitoring non-alcoholic fatty liver disease (NAFLD). Since NAFLD is becoming the dominant global cause of liver cirrhosis, and due to the close but complex interplay of liver steatosis with the coexistence of liver fibrosis, knowledge regarding NAFLD's influence on the progression of liver fibrosis is of crucial importance. Study findings, therefore, indicate the possibility of using these same diagnostic methods to evaluate the impact of NAFLD on the patient's liver fibrosis progression risk, metabolic risk factors, cardiovascular complications, and the occurrence of hepatocellular carcinoma. The mentioned areas are particularly important in light of the fact that most of the known chronic liver disease etiologies are increasingly intertwined with the simultaneous presence of NAFLD.