Macrovesicular hepatic steatosis in living related liver donors: correlation between CT and histologic findings

Diffuse and focal liver fat: advanced imaging techniques and diagnostic insights

The fatty liver disease represents a complex, multifaceted challenge, requiring a multidisciplinary approach for effective management and research. This article uses conventional and advanced imaging techniques to explore the etiology, imaging patterns, and quantification methods of hepatic steatosis. Particular emphasis is placed on the challenges and advancements in the imaging diagnostics of fatty liver disease. Techniques such as ultrasound, CT, MRI, and elastography are indispensable for providing deep insights into the liver's fat content. These modalities not only distinguish between diffuse and focal steatosis but also help identify accompanying conditions, such as inflammation and fibrosis, which are critical for accurate diagnosis and management.

Deep-learning segmentation to select liver parenchyma for categorizing hepatic steatosis on multinational chest CT

Unenhanced CT scans exhibit high specificity in detecting moderate-to-severe hepatic steatosis. Even though many CTs are scanned from health screening and various diagnostic contexts, their potential for hepatic steatosis detection has largely remained unexplored. The accuracy of previous methodologies has been limited by the inclusion of non-parenchymal liver regions. To overcome this limitation, we present a novel deep-learning (DL) based method tailored for the automatic selection of parenchymal portions in CT images. This innovative method automatically delineates circular regions for effectively detecting hepatic steatosis. We use 1,014 multinational CT images to develop a DL model for segmenting liver and selecting the parenchymal regions. The results demonstrate outstanding performance in both tasks. By excluding non-parenchymal portions, our DL-based method surpasses previous limitations, achieving radiologist-level accuracy in liver attenuation measurements and hepatic steatosis detection. To ensure the reproducibility, we have openly shared 1014 annotated CT images and the DL system codes. Our novel research contributes to the refinement the automated detection methodologies of hepatic steatosis on CT images, enhancing the accuracy and efficiency of healthcare screening processes.

Correlation between magnetic resonance imaging proton density fat fraction (MRI-PDFF) and liver biopsy to assess hepatic steatosis in obesity

Obesity is highly associated with Non-alcoholic fatty liver disease (NAFLD) and increased risk of liver cirrhosis and liver cancer-related death. We determined the diagnostic performance of the complex-based chemical shift technique MRI-PDFF for quantifying liver fat and its correlation with histopathologic findings in an obese population within 24 h before bariatric surgery. This was a prospective, cross-sectional, Institutional Review Board-approved study of PDFF-MRI of the liver and MRI-DIXON image volume before bariatric surgery. Liver tissues were obtained during bariatric surgery. The prevalence of NAFLD in the investigated cohort was as high as 94%. Histologic hepatic steatosis grades 0, 1, 2, and 3 were observed in 3 (6%), 25 (50%), 14 (28%), and 8 (16%) of 50 obese patients, respectively. The mean percentages of MRI-PDFF from the anterior and posterior right hepatic lobe and left lobe vs. isolate left hepatic lobe were 15.6% (standard deviation [SD], 9.28%) vs. 16.29% (SD, 9.25%). There was a strong correlation between the percentage of steatotic hepatocytes and MRI-PDFF in the left hepatic lobe (r = 0.82, p < 0.001) and the mean value (r = 0.78, p < 0.001). There was a strong correlation between MRI-derived subcutaneous adipose tissue volume and total body fat mass by dual-energy X-ray absorptiometry, especially at the L2-3 and L4 level (r = 0.85, p < 0.001). MRI-PDFF showed good performance in assessing hepatic steatosis and was an excellent noninvasive technique for monitoring hepatic steatosis in an obese population.

Utilizing fully-automated 3D organ segmentation for hepatic steatosis assessment with CT attenuation-based parameters

OBJECTIVES

To investigate the clinical utility of fully-automated 3D organ segmentation in assessing hepatic steatosis on pre-contrast and post-contrast CT images using magnetic resonance spectroscopy (MRS)-proton density fat fraction (PDFF) as reference standard.

MATERIALS AND METHODS

This retrospective study analyzed 362 adult potential living liver donors with abdominal CT scans and MRS-PDFF. Using a deep learning-based tool, mean volumetric CT attenuation of the liver and spleen were measured on pre-contrast (liver(L)_pre and spleen(S)_pre) and post-contrast (L_post and S_post) images. Agreements between volumetric and manual region-of-interest (ROI)-based measurements were assessed using the intraclass correlation coefficient (ICC) and Bland-Altman analysis. Diagnostic performances of volumetric parameters (L_pre, liver-minus-spleen (L-S)_pre, L_post, and L-S_post) were evaluated for detecting MRS-PDFF ≥ 5% and ≥ 10% using receiver operating characteristic (ROC) curve analysis and compared with those of ROI-based parameters.

RESULTS

Among the 362 subjects, 105 and 35 had hepatic steatosis with MRS-PDFF ≥ 5% and ≥ 10%, respectively. Volumetric and ROI-based measurements revealed ICCs of 0.974, 0.825, 0.992, and 0.962, with mean differences of -4.2 HU, -3.4 HU, -1.2 HU, and -7.7 HU for L_pre, S_pre, L_post, and S_post, respectively. Volumetric L_pre, L-S_pre, L_post, and L-S_post yielded areas under the ROC curve of 0.813, 0.813, 0.734, and 0.817 for MRS-PDFF ≥ 5%; and 0.901, 0.915, 0.818, and 0.868 for MRS-PDFF ≥ 10%, comparable with those of ROI-based parameters (0.735-0.818; and 0.816-0.895, Ps = 0.228-0.911).

CONCLUSION

Automated 3D segmentation of the liver and spleen in CT scans can provide volumetric CT attenuation-based parameters to detect and grade hepatic steatosis, applicable to pre-contrast and post-contrast images.

CLINICAL RELEVANCE STATEMENT

Volumetric CT attenuation-based parameters of the liver and spleen, obtained through automated segmentation tools from pre-contrast or post-contrast CT scans, can efficiently detect and grade hepatic steatosis, making them applicable for large population data collection.

KEY POINTS

• Automated organ segmentation enables the extraction of CT attenuation-based parameters for the target organ. • Volumetric liver and spleen CT attenuation-based parameters are highly accurate in hepatic steatosis assessment. • Automated CT measurements from pre- or post-contrast imaging show promise for hepatic steatosis screening in large cohorts.

Imaging of Alcohol-Associated Liver Disease

Alcohol-associated liver disease (ALD) continues to be a global health concern, responsible for a significant number of deaths worldwide. Although most individuals who consume alcohol do not develop ALD, heavy drinkers and binge drinkers are at increased risk. Unfortunately, ALD is often undetected until it reaches advanced stages, frequently associated with portal hypertension and hepatocellular carcinoma (HCC). ALD is now the leading indication for liver transplant. The incidence of alcohol-associated hepatitis (AH) surged during the COVID-19 pandemic. Early diagnosis of ALD is therefore important in patient management and determination of prognosis, as abstinence can halt disease progression. The spectrum of ALD includes steatosis, steatohepatitis, and cirrhosis, with steatosis the most common manifestation. Diagnostic techniques including ultrasound, CT, and MRI provide useful information for identifying ALD and excluding other causes of liver dysfunction. Heterogeneous steatosis and transient perfusion changes on CT and MRI in the clinical setting of alcohol-use disorder are diagnostic of severe AH. Elastography techniques are useful for assessing fibrosis and monitoring treatment response. These various imaging modalities are also useful in HCC surveillance and diagnosis. This review discusses the imaging modalities currently used in the evaluation of ALD, highlighting their strengths, limitations, and clinical applications.

Pancreatic steatosis is an independent risk factor for post-transplant diabetes mellitus in kidney transplant patients

BACKGROUND AND AIM

Post-transplant diabetes mellitus (PTDM) is associated with an increased risk of post-transplant cardiovascular diseases, and several risk factors of PTDM have been shown in the literature. Yet, the relationship between hepatic and pancreatic steatosis with post-transplant diabetes mellitus remains vague. We aimed to evaluate pancreatic steatosis, a novel component of metabolic syndrome, and hepatic steatosis association with post-transplant diabetes mellitus in a single-center retrospective cohort study conducted on kidney transplant recipients.

METHOD

We have performed a single-center retrospective cohort study involving all kidney transplant recipients. We have utilized pretransplant Fibrosis-4, nonalcoholic fatty liver disease fibrosis score, and abdominal computed tomography for the assessment of visceral steatosis status.

RESULTS

We have included 373 kidney transplant recipients with a mean follow-up period of 32 months in our final analysis. Post-transplant diabetes mellitus risk is associated with older age (p < .001), higher body-mass index (p < .001), nonalcoholic fatty liver disease-fibrosis score (p = .002), hepatic (p < .001) or pancreatic (p < .001) steatosis on imaging and higher pre-transplant serum triglyceride (p = .003) and glucose levels (p = .001) after multivariate analysis.

CONCLUSION

Our study illustrates that recipients' pancreatic steatosis is an independent predictive factor for post-transplant diabetes mellitus including in kidney transplant patients.

Relation between triglycerides and the severity of acute pancreatitis combined with nonalcoholic fatty liver disease: a retrospective study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) can exacerbate the severity of acute pancreatitis (AP), and this severity is worsened with increased severity of NAFLD. This study aimed to investigate the relation between serum triglyceride (TG) and the severity of AP with NAFLD by collecting clinical data from AP patients with NAFLD.

METHODS

AP patients with NAFLD were divided into 2 groups according to TG levels: hypertriglyceridemia (HTG) group and non-hypertriglyceridemia (NHTG) group.

RESULTS

In total, 598 AP patients with NAFLD were enrolled in this study, including 433 in the HTG group and 165 in the NHTG group. Compared with the NHTG group, AP patients in the HTG group were more serious (P < 0.05). The incidence of persistent organ failure (POF), especially persistent respiratory failure, and the ratio of acute peripancreatic fluid collection (APFC) were higher in the HTG group (P < 0.05). Higher TG levels were associated with a higher incidence of APFC (P < 0.05). Logistic regression analysis showed that the risk of APFC was significantly higher in moderate and severe NAFLD than in mild NAFLD.

CONCLUSION

HTG may aggravate the severity and local complications of AP combined with NAFLD.

Longitudinal changes in pancreatic volume and pancreatic fat with weight gain in Japanese without diabetes: An analysis using health check-up data

Aims/introduction

There have been few reports about the longitudinal changes in pancreas volume (PV) or pancreatic steatosis (PS) in response to obesity. In this longitudinal analysis using health check-up data, we explored changes in PV, PS and glucose metabolic indices that occurred after weight gain in Japanese without diabetes.

Materials/methods

Clinical data on 37 Japanese subjects with a ≥1 kg/m² increase in body mass index between two health check-ups and without diabetes were collected. PV, pancreas attenuation (PA) and splenic attenuation (SA) were evaluated using computed tomography (CT) images. The pancreas area was outlined by hand in multiple images with slice thickness of 2 mm, and the PV was computed by summing these areas. PS was defined as the difference between SA and PA (SA-PA). Medical records were collected, including findings on immunoreactive insulin (IRI), homeostasis model assessment of insulin resistance (HOMA-R) and beta cell function (HOMA-β). Paired t-test and Spearman's correlation coefficient were used in the analyses.

Results

The median follow-up period was 21.1 months and the mean BMI was increased from 25.5 ± 3.3 kg/m² to 27.0 ± 3.3 kg/m². PV (53.5 ± 15.9 cm³ vs. 56.2 ± 16.4 cm³) and SA-PA (8.7 ± 9.1 HU vs. 13.6 ± 10.9 HU) increased significantly after weight gain (both, P < 0.001). There were significant increases of IRI and HOMA-R with the weight gain (both, P < 0.05), whereas HOMA-β exhibited only a nonsignificant trend of increase (55.4％ (41.5-65.5) vs. 56.8％ (46.2-83.7), P = 0.07).

Conclusions

Both PV and PS were increased longitudinally with weight gain in Japanese without diabetes.

Noninvasive Tests Used in Risk Stratification of Patients with Nonalcoholic Fatty Liver Disease

As the prevalence of obesity and type 2 diabetes increases around the world, the prevalence of nonalcoholic fatty liver disease (NAFLD) has grown proportionately. Although most patients with NAFLD do not experience progressive liver disease, about 15% to 20% of those with nonalcoholic steatohepatitis can and do progress. Because liver biopsy's role in NAFLD has become increasingly limited, efforts have been undertaken to develop non-invasive tests (NITs) to help identify patients at high risk of progression. The following article discusses the NITs that are available to determine the presence of NAFLD as well as high-risk NAFLD.

How to Identify Advanced Nonalcoholic Fatty Liver Disease in the Primary Care Setting

Nonalcoholic fatty liver disease (NAFLD) affects 30 to 40% of the population globally and is increasingly considered the most common liver disease. Patients with type 2 diabetes, obesity, and cardiovascular diseases are at especially increased risk for NAFLD. Although most patients with NAFLD do not have progressive liver disease, some patients progress to cirrhosis, liver cancer, and liver mortality. Given the sheer number of patients with NAFLD, the burden of disease is enormous. Despite this large and increasing burden, identification of NAFLD patients at risk for progressive liver disease in the primary care and diabetology practice settings remains highly suboptimal. In this review, our aim is to summarize a stepwise approach to risk stratify patients with NAFLD which should help practitioners in their management of patients with NAFLD.

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.

The association of fatty liver and risk of hepatocellular carcinoma in HBV or HCV infected individuals: a systematic review and meta-analysis

BACKGROUND

Fatty liver (FL) is reportedly a risk factor for hepatocellular carcinoma (HCC) in individuals affected with Hepatitis C (HCV) or B (HBV) virus. However, the results are contradictory, necessitating a meta-analysis.

RESEARCH DESIGN AND METHODS

Sixteen relevant studies involving 88,618 individuals were retrieved from the Cochrane Library, PubMed, MEDLINE, Embase, and Scopus databases from their inception to 10 December 2022. The hazard ratios (HR) and 95% confidence intervals (CI) were analyzed.

RESULTS

Liver biopsy-proven FL may be a significant risk factor for HCC in individuals affected with HBV (univariate analyses: HR = 3.13, 95% CI = 1.69-5.79; multivariate analyses: HR = 3.42, 95% CI = 0.83-14.09) as well as HCV (univariate analyses: HR = 1.64, 95% CI = 0.93-2.90; multivariate analyses: HR = 1.75, 95% CI = 1.02-3.00). However, the presence of FL confirmed using reasonable methods other than liver biopsy may not indicate a risk for HCC in HBV-infected individuals (univariate analyses: HR = 0.90, 95% CI = 0.44-1.81; multivariate analyses: HR = 0.69, 95% CI = 0.45-1.08).

CONCLUSIONS

Biopsy-proven FL may be a significant risk factor for HCC in HCV/HBV-infected individuals. Thus, such individuals should receive suitable interventions to prevent HCC formation or at least attenuate the risk of HCC.

Hepatic fat as a novel marker for high-risk coronary atherosclerotic plaque features in familial hypercholesterolaemia

BACKGROUND & AIMS

Hepatic steatosis has been associated with increased risk of coronary artery disease. Individuals with familial hypercholesterolaemia have accelerated but variable progression of coronary artery disease. We investigated whether hepatic steatosis is associated with novel coronary atherosclerosis biomarkers in adults with heterozygous familial hypercholesterolaemia, using comprehensive coronary computed tomographic angiography.

METHODS

We conducted a cross-sectional study of 213 asymptomatic patients with familial hypercholesterolaemia (median age 54.0 years, 59 % female) who underwent coronary computed tomographic angiography for cardiovascular risk assessment in an outpatient clinic. High-risk plaque features, plaque volume and pericoronary adipose tissue attenuation were assessed. From concurrently captured upper abdominal images, severity of hepatic steatosis was computed, as liver minus spleen computed tomography attenuation and stratified into quartiles.

RESULTS

Of 213 familial hypercholesterolaemia patients, 59 % had coronary artery calcium, 36 % obstructive coronary artery disease (≥50 % stenosis) and 77 % high-risk plaque features. Increasing hepatic steatosis was associated with higher calcium scores, more high-risk plaque features and presence of obstructive coronary artery disease. Hepatic steatosis was associated with the presence of high-risk plaque features (OR: 1.48; 95 % CI: 1.09-2.00; p = 0.01), particularly in the proximal coronary segments (OR: 1.52; 95 % CI: 1.18-1.96; p = 0.001). Associations persisted on multivariable logistic regression analysis adjusting for cardiometabolic factors, obstructive coronary artery disease and calcium score. Hepatic steatosis was associated with higher plaque volumes (Q4: 499 mm³ vs Q1: 414 mm³, p = 0.02), involving mainly low attenuation and noncalcified plaques (both p = 0.03). No differences in pericoronary adipose tissue attenuation were observed.

CONCLUSIONS

Hepatic steatosis is associated with multiple indices of advanced coronary atherosclerosis in familial hypercholesterolaemia patients, particularly high-risk plaque features, independent of conventional cardiovascular risk factors and markers. This may involve specific mechanisms related to hepatic steatosis.

CLINICAL TRIAL NUMBER

N/A.

The Past, Present, and Future of Noninvasive Test in Chronic Liver Diseases

Chronic liver disease is a major global health threat and is the 11th leading cause of death globally. A liver biopsy is frequently required in assessing the degree of steatosis and fibrosis, information that is important in diagnosis, management, and prognostication. However, liver biopsies have limitations and carry a considerable risk, leading to the development of various modalities of noninvasive testing tools. These tools have been developed in recent years and have improved markedly in diagnostic accuracy. Moving forward, they may change the practice of hepatology.

High prevalence of sarcopenia and myosteatosis in patients undergoing hemodialysis

BACKGROUND AND PURPOSE

Sarcopenia is highly prevalent (28.5-40.3%) in patients undergoing hemodialysis and leads to poor clinical outcomes. However, the association between muscle quality and sarcopenia in patients receiving hemodialysis remains unclear. Therefore, we aimed to explore the association between muscle cross-sectional area (CSA) and proton-density fat-fraction (PDFF) in patients with sarcopenia undergoing hemodialysis.

METHODS

Seventy-six patients undergoing hemodialysis for > 3 months were enrolled. Their handgrip strength (HGS), short physical performance battery (SPPB) performance, and appendicular skeletal muscle mass index (ASMI) were measured. Sarcopenia was defined using the Asian Working Group for Sarcopenia 2019 consensus update. All patients underwent quantitative magnetic resonance imaging. CSA and PDFF were measured for the thigh, trunk, and gluteus muscles.

RESULTS

The prevalence of probable, confirmed, and severe sarcopenia in this study was 73.7%, 51.3%, and 22.4%, respectively. Older age (OR: 1.061, P < 0.003); lower body mass index (BMI) (OR: 0.837, P = 0.008), albumin (OR: 0.765, P = 0.004), prealbumin (OR: 0.987, P = 0.001), predialysis blood urea nitrogen (BUN) (OR: 0.842, P < 0.001), predialysis creatinine (OR: 0.993, P < 0.001), phosphorus (OR: 0.396, P = 0.047); lower CSA of the thigh (OR: 0.58, P = 0.035), third lumbar (L3) trunk (OR: 0.37, P = 0.004), gluteus minimus and medius (OR: 0.28, P = 0.001), and gluteus maximus (OR: 0.28, P= 0.001); and higher PDFF of the thigh (OR: 1.89, P = 0.036) and L3 trunk (OR: 1.71, P = 0.040) were identified as sarcopenia risk factors. The gluteus minimus and medius CSA was lower in patients with sarcopenia than in those without after adjusting for age and BMI (OR: 0.37, P = 0.017). Higher thigh (P = 0.031) and L3 trunk (P = 0.006) muscle PDFF were significantly associated with lower HGS. Furthermore, higher thigh (P = 0.011) and L3 trunk (P = 0.010) muscle PDFF were also inversely correlated with lower ASMI.

CONCLUSION

Our findings demonstrate the high prevalence of sarcopenia and myosteatosis in patients undergoing hemodialysis and might trigger a paradigm shift in intervention strategies for patients receiving hemodialysis.

Regression of Graft Steatosis After Liver Transplantation

Introduction: Liver grafts with limited steatosis are currently used for liver transplantation, but the natural history of graft steatosis is not well known. Project Aims or Questions: This program evaluation aimed at assessing changes of steatosis after liver transplantation. Design: A retrospective chart review was performed assessing presence and severity of steatosis in the liver explant and in time zero donor graft biopsies carried out at the time-point of liver transplantation on histopathology and on imaging one year thereafter in 30 well characterized patients. Results: Ten patients (33%) showed steatosis on explant. Time zero biopsy revealed steatosis in 18 grafts (60%) and no steatosis in 12 (40%). One year after transplantation, 8 patients (27%) had steatosis and 22 patients (63%) had none. Fourteen patients (47%) showed changes in steatosis: 12 showed resolution and 2 showed de novo steatosis. Explant macrovesicular steatosis was associated with presence of steatosis 1 year after transplantation (binary logistic regression model, p = 0.014), but not macrovesicular steatosis in the donor graft at time-point of transplantation. Conclusion: Resolution of graft steatosis was frequent. Presence of steatosis in the recipient's liver, but not graft steatosis, was a risk factor for steatosis 1 year after transplantation. Factors related to the recipient seem to prevail over donor-related factors in determining the persistence or de novo appearance of steatosis after liver transplantation.

Consumption of two meals per day is associated with increased intrapancreatic fat deposition in patients with type 2 diabetes: a retrospective study

INTRODUCTION

This study aimed to identify the associations between lifestyle factors and intrapancreatic fat deposition in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

The participants were 185 patients with type 2 diabetes who were hospitalized at Osaka University Hospital between 2008 and 2020 and underwent abdominal CT during hospitalization. Information regarding lifestyle factors, including the number of meals consumed per day, snacking habits, exercise habits, exercise at work, smoking habits, alcohol intake, insomnia, sleep apnea syndrome, and night-shift working, was acquired from self-administered questionnaires or medical records. We measured the mean CT values for the pancreas (P), liver (L), and spleen (S), and the visceral fat area (VFA), and quantified intrapancreatic and liver ectopic fat accumulation as P-S and L-S, respectively.

RESULTS

After adjustment for age, sex, hemoglobin A1c, and body mass index (BMI), participants who consumed two meals per day had significantly lower P-S (higher intrapancreatic fat deposition, p=0.02) than those who consumed three meals per day. There were no significant associations between the number of meals consumed and liver ectopic fat accumulation and VFA (p=0.73 and p=0.67, respectively).

CONCLUSIONS

Patients with diabetes who consumed two meals per day showed greater intrapancreatic fat deposition than those who consumed three meals per day, even after adjustment for BMI. These findings support the current guideline for diabetes treatment that skipping meals should be avoided.

Iodine Images in Dual-energy CT: Detection of Hepatic Steatosis by Quantitative Iodine Concentration Values

Hepatic steatosis is a common condition and an early manifestation of a systemic metabolic syndrome. As of today, there is no broadly accepted method for the diagnosis of hepatic steatosis in contrast-enhanced CT images. This retrospective study evaluates the potential of quantitative iodine values in portal venous phase iodine images in dual-energy CT (DECT) by measuring iodine concentrations in regions of interest (ROI) and analyzing the absolute iodine concentration of the liver parenchyma as well as three different blood-normalized iodine concentrations in a study cohort of 251 patients. An independent two sample t-test (p < 0.05) was used to compare the iodine concentrations of healthy and fatty liver. Diagnostic performance was assessed by ROC (receiver operating characteristic) curve analysis. The results showed significant differences between the average iodine concentration of healthy and fatty liver parenchyma for the absolute and for the blood-normalized iodine concentrations. The study concludes that the iodine uptake of the liver parenchyma is impaired by hepatic steatosis, and that the measurement of iodine concentration can provide a suitable method for the detection of hepatic steatosis in quantitative iodine images. Suitable thresholds of quantitative iodine concentration values for the diagnosis of hepatic steatosis are provided.

Liver Ultrasound Attenuation: An Ultrasound Attenuation Index for Liver Steatosis Assessment

OBJECTIVES

Nonalcoholic fatty liver disease (NAFLD) is the most widespread chronic liver disease type in the Western countries. Ultrasound (US) is used for NAFLD and hepatic steatosis (HS) grading. The most popular US method for NAFLD assessment is the hepatorenal index (HRI), but because of its limitations, other noninvasive methods have been developed. The Resona 7 US system has recently incorporated an US attenuation-related quantitative feature, liver ultrasound attenuation (LiSA), for HS estimation. The purpose of this study is to compare LiSA's and HRI's performance on NAFLD assessment.

METHODS

A total of 159 NAFLD patients having a magnetic resonance imaging-proton density fat fraction (MRI-PDFF) examination were examined by 2 radiologists, who performed LiSA and HRI measurements in the liver. Correlation of LiSA's and HRI's measurements with MRI-PDFF values was calculated through Pearson correlation coefficient (PCC). To further investigate the performance of LiSA and HRI, optimum cutoffs, provided by the literature, were used to correspond HS grades to MRI-PDFF results. Moreover, a receiver operating characteristic (ROC) analysis on LiSA measurements and steatosis grades was performed.

RESULTS

Magnetic resonance imaging-PDFF was better correlated with LiSA (PCC = 0.80) than HRI (PCC = 0.67). Receiver operating characteristic analysis showed better performance range for LiSA (77.8%-91.8%) than for HRI (72.8%-85.4%) on all HS grades for all studies used for corresponding MRI-PDFF values to HS grades.

CONCLUSIONS

The results indicate that LiSA is more accurate than HRI in HS differentiation and can lead to more accurate grading of HS on NAFLD patients.

Outcomes of right lobe donors with BMI≥30 for living donor liver transplantation

BACKGROUND

Donor BMI above 30 is generally considered contraindication for donor hepatectomy. We compared the donor outcomes based on BMI threshold and weight loss.

PATIENTS AND METHODS

All potential donors were identified and data were collected retrospectively. Steatosis was assessed based on liver-spleen Hounsfield unit difference and absolute liver intensity values. We compared BMI≥30 (n = 53) and BMI<30 (n = 64) donor outcomes. Donors with weight loss (WL) prior to surgery were also analyzed separately. Complications were graded by Clavien-Dindo classification.

RESULTS

All donors underwent open right donor hepatectomy. There was no difference between BMI≥30 and <30 groups except female predominance in BMI≥30 group (p = 0.006). Both groups had similar rates of complication rates in all categories, similar remnant volume, operative time, length of stay and similar postoperative liver function recovery (all p>0.05). On the other hand, donors with WL were more commonly male, had smaller graft size, and higher biliary complications rates compared to no-WL donors (all p<0.05). Multivariate binary logistics regression analysis revealed no association between BMI or WL and outcomes.

CONCLUSION

We demonstrate that donors with BMI≥30 have similar outcomes compared to BMI<30 donors with our defined selection criterion, therefore BMI≥30 is not an absolute contraindication to donate right liver, provided that there is no significant steatosis and remnant liver is satisfactory. For potential overweight donors, WL down to BMI<30 is a reasonable target. Higher biliary complication rates after WL should be investigated further. This article is protected by copyright. All rights reserved.

Computed tomography evaluation of pancreatic steatosis: correlation with COVID-19 prognosis

Aim: To investigate the relationship between pancreatic steatosis (PS) assessed on computed tomography (CT) and COVID-19 prognosis. Materials & methods: This retrospective study covers 396 patients with COVID-19 (mean age: 52.50 ± 16.86 years), who underwent unenhanced chest CT. PS was compared with clinical findings, comorbidities, requirements for hospitalization, intubation and intensive care unit (ICU), length of hospitalization and death. Results: PS was found to be strongly correlated with the severity of clinical findings and hospitalization rates (p < 0.001). In hospitalized patients, length of hospitalization (p = 0.002) and rates of ICU requirement (p = 0.003) were higher in patients with PS. Conclusion: PS, correlated with clinical severity and hospitalization requirement, is an independent risk factor for COVID-19.

Fat accumulation in the pancreas that is associated with obesity and metabolic syndrome can be used for estimating the clinical course of patients with COVID-19. Fat accumulation was determined by comparing the pancreas and spleen using computed tomography tools. In our study with 396 COVID-19 patients, the patients with fatty pancreas clearly seemed to have more severe clinical findings. Similarly, the rates of the requirement for hospitalization/intensive care unit and length of hospitalization were higher than in patients without fatty pancreas. The median length of hospitalization was 9 days in patients with fatty pancreas and 6 days in patients without fatty pancreas. However, death rates were only slightly higher in patients with fatty pancreas.

In COVID-19 patients, the patients with fatty pancreas assessed using computed tomography have a more severe clinical course, higher rates of hospitalization/ICU requirement and increased length of hospitalization compared with the patients without fatty pancreas. #COVID-19 #computed tomography #fatty pancreas.

Unenhanced computed tomography for non-invasive diagnosis of hepatic steatosis with low tube potential protocol

Background

Lowering kVp affects the image contrast and computed tomography (CT) attenuation values of low kVp CT is different from those of conventional 120-kVp scans. The purpose of this study is to determine the diagnostic performance and to establish the reference range of low-kVp unenhanced CT for the assessment of hepatic steatosis in liver transplantation donors using magnetic resonance (MR) spectroscopy as a reference standard.

Methods

This retrospective study included 165 potential donors (male:female =114:51, 36.5±12.0 years old) who underwent 100-kVp single-slice unenhanced CT scan and MR spectroscopy. The difference between hepatic and splenic attenuation (CT_L-S) and liver-to-spleen attenuation ratio (CT_L/S) were calculated. Reference standard was the fat signal fraction measured by MR spectroscopy. Limits of agreement between CT measurements and the reference standard were calculated. Areas under receiver operating characteristic curves (AUROCs) of CT_L-S and CT_L/S were compared for the diagnosis of moderate to severe steatosis. Cut-off values of CT_L-S and CT_L/S that provided a balance between sensitivity and specificity and the highest specificity using the lower limit of the reference range were calculated.

Results

Eighty-seven subjects had a non-steatotic liver. Sixty-one subjects had mild steatosis and 17 subjects had moderate to severe steatosis based on MR spectroscopy. CT_L-S and CT_L/S values were negatively correlated with the fat signal fraction (P<0.001) and limits of agreement were -8.4% to 8.4% for CT_L-S and -9.6% to 9.6% for CT_L/S. AUROCs of CT_L-S and CT_L/S for diagnosing moderate to severe steatosis were 0.956 and 0.957, respectively. Cut-off values of CT_L-S and CT_L/S for diagnosis of moderate to severe steatosis by the Youden index were -0.5 HU for CT_L-S and 0.99 for CT_L/S. Reference ranges of non-steatotic liver were -6.90 to 31.40 HU for CT_L-S and 0.89 to 1.77 for CT_L/S. Using -6.9 HU for CT_L-S and 0.89 for CT_L/S as cut-off values, the sensitivity and specificity for diagnosing moderate to severe steatosis were 70.59% and 90.54% (CT_L-S) and 76.47% and 90.54% (CT_L/S), respectively.

Conclusions

Measurements from a low-kVp unenhanced CT scan were negatively correlated with the degree of hepatic steatosis. Low-kVp unenhanced CT is a robust technique with reduced radiation exposure for diagnosing moderate to severe hepatic steatosis.

Computed tomography (CT) and magnetic resonance imaging (MRI) of diffuse liver disease: a multiparametric predictive modelling algorithm can aid categorization of liver parenchyma

BACKGROUND

Liver steatosis is common and tracking disease evolution to steatohepatitis and cirrhosis is essential for risk stratification and resultant patient management. Consequently, diagnostic tools allowing categorization of liver parenchyma based on routine imaging are desirable. The study objective was to compare established mono-factorial, dynamic single parameter and iterative multiparametric routine computed tomography (CT) and magnetic resonance imaging (MRI) analyses to distinguish between liver steatosis, steatohepatitis, cirrhosis and normal liver parenchyma.

METHODS

A total of 285 multi-phase contrast enhanced CT and 122 MRI studies with histopathological correlation of underlying parenchymal condition were retrospectively included. Parenchymal conditions were characterized based on CT Hounsfield units (HU) or MRI signal intensity (SI) measurements and calculated HU or SI ratios between non-contrast and contrast enhanced imaging time points. First, the diagnostic accuracy of mono-factorial analyses using established, static non-contrast HU and in- to opposed phase SI change cut-offs to distinguish between parenchymal conditions was established. Second, single dynamic discriminator analyses, with optimized non-contrast and enhancement HU and SI ratio cut-off values derived from the data, employing receiver operating characteristic (ROC) curve areas under the curve (AUCs) and the Youden index for maximum accuracy, were used for disease diagnosis. Third, multifactorial analyses, employing multiple non-contrast and contrast enhanced HU and SI ratio cut-offs in a nested, predictive-modelling algorithm were performed to distinguish between normal parenchyma, liver steatosis, steatohepatitis and cirrhosis. CT and MRI analyses were performed separately.

RESULTS

No single CT or MRI parameter showed significant difference between all four parenchymal conditions (each P>0.05). Mono-factorial static-CT-discriminator analyses identified liver steatosis with 75% accuracy. Mono-factorial MRI analyses identified steatosis with 89% accuracy. Single-dynamic CT parameter analyses identified normal parenchyma with 72% accuracy and cirrhosis with 75% accuracy. Single-dynamic MRI parameter analyses identified fatty parenchyma with 90% accuracy. Multifactorial CT analyzes identified normal parenchyma with 84%, liver steatosis with 95%, steatohepatitis with 95% and cirrhosis with 80% accuracy. Multifactorial predictive modelling of MRI parameters identified normal parenchyma with 79%, liver steatosis with 89%, steatohepatitis with 92% and cirrhosis with 89% accuracy.

CONCLUSIONS

Multiparametric analyses of quantitative measurements derived from routine CT and MRI, utilizing a predictive modelling algorithm, can help to distinguish between normal liver parenchyma, liver steatosis, steatohepatitis and cirrhosis.

Quantitative Evaluation of Hepatic Steatosis Using Advanced Imaging Techniques: Focusing on New Quantitative Ultrasound Techniques

Nonalcoholic fatty liver disease, characterized by excessive accumulation of fat in the liver, is the most common chronic liver disease worldwide. The current standard for the detection of hepatic steatosis is liver biopsy; however, it is limited by invasiveness and sampling errors. Accordingly, MR spectroscopy and proton density fat fraction obtained with MRI have been accepted as non-invasive modalities for quantifying hepatic steatosis. Recently, various quantitative ultrasonography techniques have been developed and validated for the quantification of hepatic steatosis. These techniques measure various acoustic parameters, including attenuation coefficient, backscatter coefficient and speckle statistics, speed of sound, and shear wave elastography metrics. In this article, we introduce several representative quantitative ultrasonography techniques and their diagnostic value for the detection of hepatic steatosis.

Is Fatty Liver Associated with Increased Mortality and Morbidity in Coronavirus Disease 2019 (COVID-19) Pneumonia?

BACKGROUND

Fatty liver has been shown to be associated with severe COVID-19 disease without any impact on mortality. This is based on heterogenous criteria for defining both fatty liver as well as the severity parameters. This study aimed to study the impact of fatty liver on the mortality and severity of disease in patients with COVID-19 pneumonia.

METHODS

In a case control study design, patients with COVID-19 pneumonia (COVID-19 computed tomography severity index [CTSI] on high-resolution computed tomography chest of ≥1) with fatty liver (defined as liver to spleen attenuation index ≤5 on noncontrast computed tomography cuts of upper abdomen) were compared with those without fatty liver. The primary outcome measure was in-hospital mortality, and the secondary outcome measures were CTSI score, need for intensive care unit (ICU) care, need for ventilatory support, duration of ICU stay, and duration of hospital stay.

RESULTS

Of 446 patients with COVID-19 pneumonia, 289 (64.7%)admitted to Max Hospital, Saket, India, between January 1, 2021, and October 30, 2021, had fatty liver. Fifty-nine of 446 patients died during the index admission. In-hospital mortality was not different between patients with fatty liver (38 [13.24%]) or without fatty liver (21 [13.81%]). COVID-19 CTSI score was found to be significantly higher among patients who had fatty liver (13.40 [5.16] vs 11.81 [5.50]; P = 0.003). There was no difference in the requirement of ICU (94 [32%] vs 62 [39.49%]; P = 0.752), requirement of ventilatory support (27 [9.34%] vs 14 [8.91%]; P = 0.385), duration of ICU stay (8.29 [6.87] vs 7.07 [5.71] days; P = 0.208), and duration of hospital stay (10.10 [7.14] vs 10.69 [8.13] days; P = 0.430) between the groups with fatty liver or no fatty liver. Similarly, no difference was found in primary or secondary outcomes measure between the group with severe fatty liver vs mild/moderate or no fatty liver. High total leucocyte count and Fibrosis-4 (FIB-4) index were independently associated with mortality.

CONCLUSIONS

Fatty liver may not be associated with increased mortality or clinical morbidity in patients who have COVID-19 pneumonia.

Determinants of Pancreatic Steatosis: A Retrospective Observational Study

BACKGROUND Metabolic syndrome affects 35% of the adult population in developed countries associated with non-alcoholic steatohepatitis, insulin resistance, and cardiovascular events. Fatty infiltration of the pancreas, or pancreatic steatosis, is a risk factor for acute pancreatitis, pancreatic malignancies, and diabetes mellitus, yet its relationship with metabolic syndrome is not well defined. METHODS We performed a single-centered retrospective observational study of 322 healthy subjects (subjects volunteering to be kidney transplant donors, mean age=46.3±13.5, 163 men and 159 women) in the last 2 years (July 2018-February 2020) from our institution. Pancreatic steatosis and hepatosteatosis were confirmed by computed tomography. RESULTS Pancreatic steatosis was present in 26.3% (85/322) of the subjects, and this finding correlated with age, body mass index (BMI), male sex, a family history of diabetes, creatinine, cystatin C, uric acid, low-density lipoprotein (LDL) cholesterol, triglycerides, glycemia, hemoglobin, transverse body diameter, and subcutaneous fat thickness levels by univariable logistic regression. On multiple linear regression only age (95% CI 1.01, 1.06), BMI (95% CI 1.01, 1.19), male sex (95% CI 1.49-5.99), uric acid (95% CI 1.01, 1.76), and subcutaneous fat thickness levels (95% CI 1.21-2.36) remained independently associated with pancreatic steatosis. CONCLUSION Pancreatic steatosis is common and associated with obesity, elevated serum uric acid, subcutaneous fat thickness, and male sex. Future studies are needed to evaluate if there are specific clinical consequences to the presence of pancreatic steatosis.

Imaging Evaluation of Living Liver Donor Candidates: Techniques, Protocols, and Anatomy

The need for liver transplants is increasing because the prevalence of liver diseases and the indications for transplants are growing. In response to the shortage of grafts from deceased donors, more transplants are being performed worldwide with grafts from living donors. Radiologic evaluation is an integral component in the assessment of donor candidates to ensure their eligibility and to choose the most appropriate surgical approach. MRI is the preferred modality for evaluation of the liver parenchyma and biliary tree. In most centers, a combination of MRI and CT is used to take advantage of the higher spatial resolution of CT for evaluation of arteries. However, MRI-only assessment is feasible. In addition to assessment of the liver parenchyma for abnormalities such as steatosis, a detailed evaluation of the hepatic vascular and biliary system for pertinent anatomic variants is crucial, because these variants can affect surgical techniques and outcomes in both recipients and donors. In this pictorial article, after a brief review of the most common surgical techniques and postsurgical liver anatomy, the biliary and vascular anatomy are discussed, with specific attention paid to the variants that are pertinent to this surgical procedure. The roles of liver segmentation and volumetric assessment and current imaging techniques and protocols are also discussed. Online supplemental material is available for this article. ©RSNA, 2021.

Quantification of liver and muscular fat using contrast-enhanced Dual Source Dual Energy Computed Tomography compared to an established multi-echo Dixon MRI sequence

PURPOSE

To investigate the feasibility of liver fat quantification in contrast-enhanced dual source dual energy computed tomography (DECT) using multi-echo Dixon magnetic resonance imaging (MRI) as reference standard.

METHOD

Patients who underwent MRI of the liver including a multi-echo Dixon sequence for estimation of proton density fat fraction in 2017 as well as contrast-enhanced DECT imaging of the abdomen were included in this retrospective, monocentric IRB approved study. Furthermore, patients with a hepatic fat amount >5% who were examined in 2018 with MRI and DECT were included. The final study group consisted of 81 patients with 90 pairs of examinations. Analysis of parameter maps was performed manually using congruent regions of interest which were placed in the liver parenchyma, in the erector spinae muscles, and psoas major muscles.

RESULTS

Mean patient age was 61 ± 13 years. Median time between MRI and DECT was 48 days. MRI liver fat quantification resulted in a median of 3.8% (IQR: 2.2-8.2%) compared to 1.8% (IQR: 0-6.3%) in DECT (p < 0.001), with a Spearman correlation of 0.73. Bland-Altman analysis resulted in a systematic underestimation of liver fat in DECT, with a mean difference of -1.7%. Fat quantification in the erector spinae muscles (p = 0.257) and the psoas major muscles (p = 0.208) was not significantly different in DECT compared to MRI.

CONCLUSIONS

Liver and muscular fat quantification in portal-venous phase DECT is feasible with good to excellent correlation compared to a multi-echo Dixon MRI sequence analysis. While there is an underestimation of the liver fat content in DECT, there are no significant differences between DECT and MRI fat quantification of the erector spinae and psoas major muscles.

Role of hepatosteatosis in the prognosis of COVID 19 disease

Purpose

To measure the degree of fatty liver using non-contrast enhanced chest computed tomography (CT) and investigate its relationship with the severity and prognosis of coronavirus disease 2019 (COVID-19) in adult patients.

Methods

This retrospective study included consecutive patients who had been diagnosed with COVID-19 using real-time reverse-transcription polymerase chain reaction (RT-PCR) and subsequently underwent non-contrast enhanced chest CT between October 10 and December 10, 2020. Hepatic attenuation values were measured from Couinaud segments 2, 4, and 8 based on the CT images and the relationships between these values and the Pneumonia Severity Score (PSS), requirement of hospitalization, and the length of hospital and intensive care unit (ICU) stay were analyzed.

Results

The study included 414 patients (182 were female, 43.96%), among whom 106 (25.6%) were diagnosed with hepatosteatosis (HS). In the patients with HS, the PSS scores were higher (10.8 ± 4.96 vs. 8.07 ± 5.12; p < 0.001), and 69 (65%) received inpatient care. Moreover, the number of HS patients who received inpatient care was 1.99 (95% confidence interval (CI) 1.26–3.15, p < 0.003) times higher than that of the non-HS patients. No significant difference was found between the HS and non-HS patients with regard to the length of hospital or ICU stay.

Conclusion

HS can be easily evaluated using non-contrast enhanced chest CT in COVID-19 patients and can be used as a prognostic marker to determine the requirement of hospitalization.

Magnetic Resonance Spectroscopy of Hepatic Fat from Fundamental to Clinical Applications

The number of individuals suffering from fatty liver is increasing worldwide, leading to interest in the noninvasive study of liver fat. Magnetic resonance spectroscopy (MRS) is a powerful tool that allows direct quantification of metabolites in tissue or areas of interest. MRS has been applied in both research and clinical studies to assess liver fat noninvasively in vivo. MRS has also demonstrated excellent performance in liver fat assessment with high sensitivity and specificity compared to biopsy and other imaging modalities. Because of these qualities, MRS has been generally accepted as the reference standard for the noninvasive measurement of liver steatosis. MRS is an evolving technique with high potential as a diagnostic tool in the clinical setting. This review aims to provide a brief overview of the MRS principle for liver fat assessment and its application, and to summarize the current state of MRS study in comparison to other techniques.

Dual-energy CT of the liver: True noncontrast vs. virtual noncontrast images derived from multiple phases for the diagnosis of fatty liver

PURPOSE

To evaluate the difference in liver density and to compare the performance to diagnose fatty liver between true noncontrast (TNC) images and virtual noncontrast (VNC) images generated from dual-energy CT (DECT).

MATERIALS AND METHODS

Patients who underwent liver dynamic DECT and MRI were included (n = 49). Two observers measured the liver and spleen densities on TNC images and three VNC images from the arterial, portal and delayed phases of DECT (VNCa, VNCp and VNCd, respectively). The liver-minus-spleen density (density L-S) and liver-to-spleen ratio (density L/S) were calculated. The CT parameters were compared between normal liver patients and fatty liver patients by using the independent t-test. Differences and agreements between measurements on TNC images and VNC images were evaluated by using the paired t-test and Bland-Altman analysis. Receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic performance of CT parameters for diagnosing fatty liver.

RESULTS

All CT parameters measured on TNC and VNC images were significantly higher in normal liver patients than in fatty liver patients. Although the mean liver densities on VNC images were significantly lower than those on TNC images, all CT parameters showed good agreement between TNC images and VNC images. The diagnostic performances of CT parameters on VNC images were not significantly different from those on TNC images.

CONCLUSION

Although the liver and spleen density on VNC images was significantly lower than that on TNC images, the diagnostic performances of CT parameters on three VNC images from multiple phases were similar to those on TNC images for diagnosing fatty liver.

Comparison of Multimaterial Decomposition Fat Fraction with DECT and Proton Density Fat Fraction with IDEAL IQ MRI for Quantification of Liver Steatosis in a Population Exposed to Chemotherapy

Introduction:

Oncologic patients who develop chemotherapy-associated liver injury (CALI) secondary to chemotherapy treatment tend to have worse outcomes. Biopsy remains the gold standard for the diagnosis of hepatic steatosis. The purpose of this article is to compare 2 alternatives: Proton-Density-Fat-Fraction (PDFF) MRI and MultiMaterial-Decomposition (MMD) DECT.

Materials and Methods:

49 consecutive oncologic patients treated with Chemotherapy underwent abdominal DECT and abdominal MRI within 2 weeks of each other. Two radiologists tracked Regions of Interest independently both in the PDFF fat maps and in the MMD DECT fat maps. Non-parametric exact Wilcoxon signed rank test and Cohen’s K were used to compare the 2 sequences and to evaluate the agreement.

Results:

There was no statistically significant difference in the fat fraction measured as a continuous value between PDFF and DECT between 2 readers. Within the same imaging method (PDFF) the degree of agreement based on the k coefficient between reader 1 and reader 2 is 0.88 (p-value < 0.05). Similarly, for single-source DECT(ssDECT) the degree of agreement based on the k coefficient between reader 1 and reader 2 is 0.97 (p-value < 0.05).

Conclusions:

The results of this study demonstrate that the hepatic fat fraction of ssDECT with MMD are not significantly different from PDFF. This could be an advantage in an oncological population that undergoes serial CT scans for follow up of chemotherapy response.

Non-alcoholic fatty liver disease with reduced myocardial FDG uptake is associated with coronary atherosclerosis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has a significant role in the development of coronary atherosclerosis, independent of traditional cardiovascular and metabolic risk factors. However, the role of myocardial glucose uptake in NAFLD patients who develop coronary atherosclerosis was unclear. The aim of the present study thus was to investigate the association between NAFLD with characteristic of coronary atherosclerotic plaque and myocardial glucose uptake measured by using 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET).

METHODS AND RESULTS

A total of 418 consecutive subjects who had undergone FDG PET/computed tomography (CT) and coronary computed tomography angiography (CCTA) were retrospectively investigated. Fatty liver was assessed by unenhanced CT. Coronary atherosclerotic plaques and stenosis on CCTA were evaluated. The metabolic parameters were measured on PET images. The ratio of the maximum myocardium FDG value to the mean standardized uptake value of liver (SUVratio) was calculated to estimate myocardial glucose uptake. The association of myocardial glucose uptake with NAFLD and coronary atherosclerosis was determined by multivariate logistic regression analysis. The proportion of low SUVratio in patients with NAFLD was significantly higher compared to those without NAFLD (45.00% vs 19.82%, P < .001). There was a significantly negative correlation between myocardial FDG uptake and hepatic steatosis in association trend analysis (P < .001). When the proportion of individuals with non-calcified plaque on CCTA is stratified by quartiles of SUVratio, patients with low quartiles of SUVratio were more likely to have higher proportion of non-calcified plaque than those with high quartiles of SUVratio (Q1 and Q2 vs Q3 and Q4, P = .003). The trend analysis presented correlated inversely relationship between non-calcified plaque and myocardial SUVratio (P = .001). Moreover, multivariate regression analysis showed that the low SUVratio was independently associated with NAFLD, non-calcified plaque, and significant stenosis after adjusting for clinically important factors.

CONCLUSION

We demonstrated that the presence of reduced myocardial glucose uptake in patients with NAFLD was independently associated with non-calcified plaque and significant stenosis, suggesting an increased risk of coronary atherosclerosis and future cardiovascular events.

Impact of hepatic steatosis on outcomes after left ventricular assist device implantation

BACKGROUND

This single-center, retrospective study evaluates the impact of hepatic steatosis on outcomes after continuous-flow left ventricular assist device (LVAD) implantation.

METHODS

Adults undergoing LVAD implantation between 2004 and 2018 with a preoperative noncontrast-enhanced chest and abdominal computed tomography scan were included in the study. Patients were stratified as with and without radiographic signs of hepatic steatosis. The primary outcome was survival, and secondary outcomes included rates of postimplant adverse events.

RESULTS

A total of 203 patients were included in the study. 27.6% (n = 56) had radiographic signs of hepatic steatosis. Hepatic steatosis group had a higher body mass index (30.1 vs. 27.0, p < .01), model for end-stage liver disease excluding international normalized ratio score (16.8 vs. 15.1, p = .05), and incidence of diabetes (53.6% vs. 35.4%, p = .02). The rates of postimplant adverse events, including bleeding, infection, reoperation, renal failure, hepatic dysfunction, stroke, and right ventricular failure, were similar between the groups (all, p > .05). Unadjusted survival was comparable between the groups at 30-days, 90-days, 1-year, and 2-year following LVAD implantation (all, p > .05). In addition, hepatic steatosis did not impact risk-adjusted overall mortality when modeled as a categorical variable (odds ratio [OR]: 0.72, 95% confidence interval [CI]: 0.46-1.13; p = .15).

CONCLUSIONS

This study demonstrates that the presence of preoperative hepatic steatosis on imaging is not predictive of increased morbidity or mortality following LVAD implantation. Despite the association with obesity, metabolic diseases, and heart failure, hepatic steatosis on imaging appears to have a limited role in patient selection or prognostication in LVAD patients.

Metabolic parameters in smokers undergoing smoking reduction

Introduction

Few human studies have explored the mechanisms of smoking-induced insulin resistance. Aims: To prospectively examine the metabolic changes of smoking reduction.

Methods

Cigarette smokers (n = 22; ½-2 packs per day) were enrolled in a smoking reduction program (counseling plus bupropion × 8 weeks; Phase I) followed by monitoring only (no counseling or bupropion × 16 weeks; Phase II). We serially measured exhaled carbon monoxide (CO) and urine nicotine metabolites; fat distribution, and metabolic parameters by hyperinsulinemic clamps including hepatic glucose output (HGO) and indirect calorimetry, adjusted for total caloric intake and expenditure.

Results

CO and nicotine metabolite levels fell with smoking reduction during Phase I (all p < 0.05), without any further changes through Phase II. Central-to-peripheral fat ratio increased during Phase I, but then fell during Phase II (all p < 0.05). Over 24 weeks, basal HGO fell (p = 0.02); and falling CO and nicotine metabolite levels correlated inversely with changes in glucose oxidation, and directly with changes in weight (all p < 0.05).

Conclusions

Smoking reduction produced a transient worsening of central fat redistribution followed by a more significant improvement; along with other net beneficial metabolic effects.

Usefulness of Preoperative Magnetic Resonance Spectroscopy to Improve the Safety of a Living Liver Donor

OBJECTIVES

The steatosis of graft liver is an important factor in liver transplant that determines the graft function in the recipient and the recovery of the remnant liver in the living donor. We analyzed the data of living donors from our center to evaluate whether magnetic resonance imaging and magnetic resonance spectroscopy can replace liver biopsy.

MATERIALS AND METHODS

From May 2010 to May 2019, data from a total of 239 living donors was collected. There were 84 patients who had no magnetic resonance imaging or magnetic resonance spectroscopy data, and they were excluded. The result of preoperative liver biopsy was compared with preoperative magnetic resonance imaging and magnetic resonance spectroscopy data. The steatosis was defined by the degree of macrosteatosis.

RESULTS

The magnetic resonance imaging of the fat fraction was a good parameter to predict fatty changes between normal and fatty liver groups (3.09 ± 3.38% for normal 7.48 ± 4.07% for fatty liver; P < .001). The magnetic resonance spectroscopy was also a good parameter to predict fatty changes between normal and fatty liver groups (2.09 ± 1.43% for normal and 6.89 ± 2.68% for fatty liver; P < .001). Linear regression showed that pathology results were significantly correlated with magnetic resonance spectroscopy (P < .001, R2 = 0.604) but not with magnetic resonance imaging (P < .001, R2 = 0.227).

CONCLUSIONS

Magnetic resonance spectroscopy has several benefits for quantifying hepatic steatosis during a living donor liver transplant evaluation, including no radiation exposure, and a noninvasive procedure. Moreover, preoperative magnetic resonance spectroscopy can determine an anatomic variation of the bile duct, which helps improve the safety of the living donor. However, more clinical data and further studies are needed to ensure that preoperative magnetic resonance spectroscopy is essential.

The comparison of pancreatic and hepatic steatosis in healthy liver donor candidates

The aim of this study was to investigate the relationship between nonalcoholic fatty liver disease (NAFLD) and pancreatic steatosis (PS) in patients with biopsy-proven NAFLD. 228 patients with biopsy-proven NAFLD patients who admitted to the Faculty of Medicine of Demiroglu Bilim University between 2004 and 2019 were included in the study. Demographic, laboratory, histological and radiological findings of the patients were recorded retrospectively. Hepatosteatosis (HS) levels were measured by both CT and biopsy, while PS levels were measured by 3 different CT-based techniques. 89 (39%) of the patients were female and 139 (61%) were male. The mean body mass index (BMI) was 27.2 ± 4.0. Biochemical parameters were within normal limits. Liver biopsy showed a significant correlation with HS grade on CT scan (p < 0.001). When CT findings were compared, a significant correlation was found between PS and HS (p < 0.05), but there was no correlation between the HS level in biopsy and the pancreatic adiposity on CT (p > 0.05). Our study was the first to compare biopsy-proven NAFLD and PS, and no correlation was found between biopsy-proven NAFLD and PS.

Double-blind placebo-controlled randomized trial of N-acetylcysteine infusion following live donor liver transplantation

BACKGROUND

The role of N-acetylcysteine (NAC) in improving outcomes following live donor liver transplantation (LDLT) is not well established. We designed a randomized double-blind placebo-controlled trial to study the role of NAC infusion in recipients undergoing LDLT.

METHODS

We assigned 150 patients who underwent LDLT by computer-generated random sequence on 1:1 ratio to either NAC group or placebo group. Patients in the NAC group received NAC infusion which was started at beginning of graft implantation at an initial loading dose of 150 mg/kg/h over 1 h, followed by 12.5 mg/kg/h for 4 h and then at 6.25 mg/kg/h continued for 91 h. Placebo group received normal saline. The primary endpoint was composite occurrence of acute kidney injury (AKI) and early allograft dysfunction (EAD) in the recipient. Secondary endpoints included levels of bilirubin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, INR, primary graft non-function, intraoperative bleeding, post-transplant hospital stay and in-hospital mortality.

RESULTS

The composite endpoint did not show any significant difference between the NAC and placebo group (21.3% vs 29.3%, p = 0.35). Peak AST (425.65 IU/L vs 702.24 IU/L, p = 0.02) and peak ALT (406.65 IU/L vs 677.99 IU/L, p = 0.01) levels were significantly lower in the study group. Time to normalization of transaminases was also significantly low in the study group.

CONCLUSIONS

Perioperative NAC infusion following LDLT resulted in significantly lower postoperative AST and ALT levels. Rapid normalization of transaminases was also observed. This, however, did not translate to improvement in AKI or EAD.

Hepatic steatosis as an independent risk factor for severe disease in patients with COVID-19: A computed tomography study

Background and Aim

Hepatic steatosis (HS) is associated with diabetes, hypertension, and obesity, comorbidities recently related to COVID-19 severity. Here, we assessed if tomographic HS is also a risk factor for severe COVID-19 pneumonia.

Methods

We included 213 patients with a positive real time polymerase chain reaction (RT-PCR) test and chest computed tomography (CT) from an out-hospital facility and a hospital. We obtained information on demographics; weight; height; smoking history; diabetes; hypertension; and cardiovascular, lung, and renal disease. Two radiologists scored the CO-RADs system (COVID-19 Reporting and Data System) (1 = normal, 2 = inconsistent, 3-4 = indeterminate, and 5 = typical findings) and the chest CT severity index (≥20 of 40 was considered severe disease). They evaluated the liver-to-spleen ratio (CTL/S) and defined tomographic steatosis as a CTL/S index ≤0.9. We used descriptive statistics, χ2 and t student tests, logistic regression, and reported odds ratio (OR) with 95% confidence interval (CI).

Results

Of the patients, 61% were men, with a mean age of 51.2 years, 48.3% were CO-RADs 1 and 51.7% CO-RADs 2-5. Severe tomographic disease was present in 103 patients (48.4%), all CO-RADs 5. This group was older; mostly men; and with a higher prevalence of obesity, hypertension, diabetes, and HS (69.9 vs 29%). On multivariate analysis, age (OR 1.058, 95% CI 1.03-1.086, P < 0.0001), male gender (OR 1.9, 95% CI 1.03-3.8, P = 0.04), and HS (OR 4.9, 95% CI 2.4-9.7, P < 0.0001) remained associated.

Conclusion

HS was independently associated with severe COVID pneumonia. The physiopathological explanation of this finding remains to be elucidated. CTL/S should be routinely measured in thoracic CT scans in patients with COVID-19 pneumonia.

Changes of Branched-Chain Amino Acids and Ectopic Fat in Response to Weight-loss Diets: the POUNDS Lost Trial

CONTEXT

Recent evidence has related circulating branch-chained amino acids (BCAAs) to ectopic fat distribution.

OBJECTIVE

To investigate the associations of changes in plasma BCAAs induced by weight-loss diet interventions with hepatic fat and abdominal fat, and potential modification by different diets.

DESIGN, SETTING, AND PARTICIPANTS

The current study included 184 participants from the 2-year Preventing Overweight and Using Novel Dietary Strategies (POUNDS Lost) trial with repeated measurements on plasma BCAAs, hepatic fat, and abdominal fat over 2 years.

MAIN OUTCOME MEASURES

Repeated measurements of hepatic fat, abdominal fat distribution, including visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), and total adipose tissue (TAT).

RESULTS

Over 2 years, a decrease in total plasma BCAAs was significantly associated with improvement in hepatic density (a marker for hepatic fat; P = 0.02) and reductions in abdominal fat, including VAT, SAT, and TAT (all P < 0.05) in the main analyses. Additionally, we observed that decreases in BCAAs were associated with decreased insulin, homeostasis model assessment of insulin resistance, and triglycerides, independent of weight loss (all P < 0.05). Moreover, we found that dietary protein intake significantly modified the relation between changes in total plasma BCAAs and hepatic density at 6 months (Pinteraction = 0.01). Participants with a larger decrease in total BCAAs showed a greater increase in hepatic density when consuming a high-protein diet, compared with those with a smaller decrease or increase in total BCAAs.

CONCLUSIONS

Our findings indicate that weight-loss diet-induced decrease in plasma BCAAs is associated with reductions of hepatic and abdominal fat. In addition, dietary protein intake may modify these associations.

Association between non-alcoholic fatty liver disease and myocardial glucose uptake measured by 18F-fluorodeoxyglucose positron emission tomography

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has emerged as an independent risk factor for cardiovascular diseases. However, there were few studies evaluating the condition of myocardial glucose metabolism in patients with NAFLD. Therefore, the aim of this study was to investigate the association between NAFLD and myocardial glucose uptake assessed by using 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) and whether or not alteration of myocardial glucose uptake could be an indicator linking to cardiac dysfunction in NAFLD individuals.

METHODS AND RESULTS

A total of 743 asymptomatic subjects (201 with NAFLD, 542 without NAFLD) were retrospectively studied. The ratio of maximum myocardium FDG uptake to the mean standardized uptake value of liver (SUVratio) was calculated to estimate myocardial glucose uptake by using 18F-FDG PET. The diagnosis of fatty liver and fatty liver grading was confirmed by unenhanced CT according to diagnostic criterion of previous studies. The myocardial geometric and functional data were obtained by echocardiogram. Myocardial glucose uptake was significantly lower in individuals with NAFLD compared with those without fatty liver (P < .001). When analysis of association trend was performed, SUVratio quartiles showed correlated inversely and strongly with liver steatosis (P < .001). NAFLD patients with lower myocardial glucose uptake were more likely to have higher proportion of increased LV filling pressure (P < .05). A significant relationship between myocardial SUVratio and E/e' ratio was presented in the trend analysis (P < .05). Moreover, multivariate regression analysis showed that myocardial glucose uptake was independently associated with NAFLD after adjusting for clinical important factors (all P < .001).

CONCLUSIONS

The presence of NAFLD in otherwise healthy subjects is closely associated with decreased myocardial glucose uptake assessing by 18F-FDG PET imaging. Furthermore, the NAFLD individuals with lower myocardial glucose uptake are more likely to have high risk of having impaired diastolic heart function.

Quantification of pancreas fat on dual-energy computed tomography: comparison with six-point Dixon magnetic resonance imaging

OBJECTIVES

Although it is important to quantify the degree of fatty degeneration of the pancreas, it is difficult to make such a quantification using conventional computed tomography (CT). The present study evaluated the feasibility of pancreatic fat quantification by dual-energy CT (DECT) compared with T2*-corrected six-point Dixon magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Twenty-eight patients who underwent both DECT (100 and 150 kVp) and Dixon MRI without the use of contrast agents were analyzed. The region of interest (ROI) was placed at the head and body/tail of the pancreas on fat volume fraction (FVF) maps generated using the multi-material decomposition (MMD) algorithm on DECT. The FVF (%) of pancreatic parenchyma measured by DECT (CT-FVF) was compared with that measured on FVF maps calculated using Dixon MRI (MR-FVF) using the Spearman rank correlation coefficient.

RESULTS

The median CT-FVF (%) values of the head and body/tail of the pancreas on DECT were 14.2% (range 0.1-81.2%) and 9.4% (range 0-40.8%), respectively. The median MR-FVF (%) values of the head and body/tail of the pancreas on Dixon MRI were 12.2% (range 1.2-80.9%) and 8.1% (range 0.3-43.7%), respectively. CT-FVF (%) measured by DECT showed a significant correlation with the MR-FVF (%) measured by Dixon MRI in the head of the pancreas (ρ = 0.631, P < 0.001) as well as the body/tail of the pancreas (ρ = 0.526, P = 0.004).

CONCLUSION

DECT may be useful for quantifying the degree of fatty degeneration of the pancreas.

Advances in Imaging of Diffuse Parenchymal Liver Disease

There are >1.5 billion people with chronic liver disease worldwide, causing liver diseases to be a significant global health issue. Diffuse parenchymal liver diseases, including hepatic steatosis, fibrosis, metabolic diseases, and hepatitis cause chronic liver injury and may progress to fibrosis and eventually hepatocellular carcinoma. As early diagnosis and treatment of these diseases impact the progression and outcome, the need for assessment of the liver parenchyma has increased. While the current gold standard for evaluation of the hepatic parenchymal tissue, biopsy has disadvantages and limitations. Consequently, noninvasive methods have been developed based on serum biomarkers and imaging techniques. Conventional imaging modalities such as ultrasound, computed tomography scan, and magnetic resonance imaging provide noninvasive options for assessment of liver tissue. However, several recent advances in liver imaging techniques have been introduced. This review article focuses on the current status of imaging methods for diffuse parenchymal liver diseases assessment including their diagnostic accuracy, advantages and disadvantages, and comparison between different techniques.