Unenhanced CT for assessment of macrovesicular hepatic steatosis in living liver donors: comparison of visual grading with liver attenuation index

Elevated neutrophil-to-lymphocyte ratio combined with decreased lymphocyte-to-monocyte ratio is associated with increased peripheral airway resistance in patients with hepatic steatosis

Although the link between hepatic steatosis and lung function has been confirmed, the focus has largely been on central airways. The association between hepatic steatosis and increased peripheral airway resistance has not yet been explored. Hepatic steatosis and increased peripheral resistance are connected with immunity dysregulation. High neutrophil-to-lymphocyte ratio (NLR) and low lymphocyte-to-monocyte ratio (LMR) have been recognized as indicators of immunity dysregulation. In this study, the association between hepatic steatosis and increased peripheral airway resistance was evaluated, and the effect of immunity dysregulation (high NLR/low LMR) on the increased peripheral airway resistance among patients with hepatic steatosis was explored. In this retrospective study, chest or abdomen CT scans and spirometry/impulse oscillometry (IOS) from 2018 to 2019 were used to identify hepatic steatosis and increased central/peripheral airway resistance in patients. Among 1391 enrolled patients, 169 (12.1%) had hepatic steatosis. After 1:1 age and abnormal ALT matching was conducted, clinical data were compared between patients with and without hepatic steatosis. A higher proportion of patients with hepatic steatosis had increased peripheral airway resistance than those without hepatic steatosis (52.7% vs 40.2%, P = .025). Old age, high body mass index, history of diabetes, and high NLR/low LMR were significantly correlated with increased peripheral airway resistance. The presence of hepatic steatosis is associated with increased peripheral airway. High NLR/low LMR is an independent associated factor of increased peripheral airway resistance in patients with hepatic steatosis. It is advisable for patients with hepatic steatosis to regularly monitor their complete blood count/differential count and undergo pulmonary function tests including IOS.

Automated hepatic steatosis assessment on dual-energy CT-derived virtual non-contrast images through fully-automated 3D organ segmentation

PURPOSE

To evaluate the efficacy of volumetric CT attenuation-based parameters obtained through automated 3D organ segmentation on virtual non-contrast (VNC) images from dual-energy CT (DECT) for assessing hepatic steatosis.

MATERIALS AND METHODS

This retrospective study included living liver donor candidates having liver DECT and MRI-determined proton density fat fraction (PDFF) assessments. Employing a 3D deep learning algorithm, the liver and spleen were automatically segmented from VNC images (derived from contrast-enhanced DECT scans) and true non-contrast (TNC) images, respectively. Mean volumetric CT attenuation values of each segmented liver (L) and spleen (S) were measured, allowing for liver attenuation index (LAI) calculation, defined as L minus S. Agreements of VNC and TNC parameters for hepatic steatosis, i.e., L and LAI, were assessed using intraclass correlation coefficients (ICC). Correlations between VNC parameters and MRI-PDFF values were assessed using the Pearson's correlation coefficient. Their performance to identify MRI-PDFF ≥ 5% and ≥ 10% was evaluated using receiver operating characteristic (ROC) curve analysis.

RESULTS

Of 252 participants, 56 (22.2%) and 16 (6.3%) had hepatic steatosis with MRI-PDFF ≥ 5% and ≥ 10%, respectively. LVNC and LAIVNC showed excellent agreement with LTNC and LAITNC (ICC = 0.957 and 0.968) and significant correlations with MRI-PDFF values (r = - 0.585 and - 0.588, Ps < 0.001). LVNC and LAIVNC exhibited areas under the ROC curve of 0.795 and 0.806 for MRI-PDFF ≥ 5%; and 0.916 and 0.932, for MRI-PDFF ≥ 10%, respectively.

CONCLUSION

Volumetric CT attenuation-based parameters from VNC images generated by DECT, via automated 3D segmentation of the liver and spleen, have potential for opportunistic hepatic steatosis screening, as an alternative to TNC images.

Retrospective computed tomography assessment of chemotherapy-related pneumonia with severity screening in pediatric acute lymphoblastic leukemia by radiological imaging

Objectives

To evaluate the radiological imaging-guided severity along the pneumonia course and evaluate the chest computed tomography (CT) findings of chemotherapy-related pneumonia in children with acute lymphoblastic leukemia (ALL).

Materials and methods

A retrospective database review of children with ALL was conducted from March 2016 to August 2021 to identify cases with CT images who developed pneumonia during the chemotherapy course. A total of 51 children with ALL developed pneumonia were ultimately included (31 boys and 20 girls, mean age: 6 ± 4 years [standard deviation]). Each child's demographics, medical records, and laboratory results were collected. The CT images were then reviewed and the radiologic severity index (RSI) was calculated based on the regional opacity and implicated volume. A t-test, U test, Pearson's Chi-square test, and Fisher's exact test were performed to compare the clinical or radiologic features between the severe and moderate cases. The linear regression models were employed to analyze the correlation of RSIs with other clinical features.

Results

Eleven children (22 %, 11/51) displayed severe phenotypes associated with respiratory failure. The ground glass opacity (GGO) frequently appeared (65 % of CT images). The baseline RSI was positively associated with the lowest lymphocyte (p = .003), neutrophil (p = .01) counts, and the highest C-reactive protein level (p = .04). The peak RSI may predict severe phenotypes at a cutoff of 4.5 (AUC 0.76 [0.61, 0.91]) with 73 % sensitivity and 63 % specificity.

Conclusion

The chest CT images of children with chemotherapy-related pneumonia displayed clinically related baseline RSI and a peak RSI of >4.5 of 36 predicted severe phenotypes.

CT Texture Analysis in Nonalcoholic Fatty Liver Disease (NAFLD)

Background

Nonalcoholic fatty liver disease (NAFLD) is the most common form of liver disease worldwide. There are limited biomarkers that can detect progression from simple steatosis to nonalcoholic steatohepatitis (NASH). The purpose of our study was to utilize CT texture analysis to distinguish steatosis from NASH.

Methods

16 patients with NAFLD (38% male, median (interquartile range): age 57 (48-64) years, BMI 37.5 (35.0-46.8) kg/m2) underwent liver biopsy and abdominal non-contrast CT. CT texture analysis was performed to quantify gray-level tissue summaries (e.g., entropy, kurtosis, skewness, and attenuation) using commercially available software (TexRad, Cambridge England). Logistic regression analyses were performed to quantify the association between steatosis/NASH status and CT texture. ROC curve analysis was performed to determine sensitivity, specificity, AUC, 95% CIs, and cutoff values of texture parameters to differentiate steatosis from NASH.

Results

By histology, 6/16 (37%) of patients had simple steatosis and 10/16 (63%) had NASH. Patients with NASH had lower entropy (median, interquartile range (IQR): 4.3 (4.1, 4.8) vs. 5.0 (4.9, 5.2), P = 0.013) and lower mean value of positive pixels (MPP) (34.4 (21.8, 52.2) vs. 66.5 (57.0, 70.7), P = 0.009) than those with simple steatosis. Entropy values below 4.73 predict NASH with 100% (95%CI: 67-100%) specificity and 80% (50-100%) sensitivity, AUC: 0.88. MPP values below 54.0 predict NASH with 100% (67-100%) specificity and 100% (50-100%) sensitivity, AUC 0.90.

Conclusion

Our study provides preliminary evidence that CT texture analysis may serve as a novel imaging biomarker for disease activity in NAFLD and the discrimination of steatosis and NASH.

Relationships between intra-pancreatic fat deposition and lifestyle factors: a cross-sectional study

Aims

The excess deposition of intra-pancreatic fat deposition (IPFD) has been reported to be associated with type 2 diabetes, chronic pancreatitis, and pancreatic ductal adenocarcinoma. In the current study, we aimed to identify a relationship between lifestyle factors and IPFD.

Materials and methods

99 patients admitted to the Osaka University Hospital who had undergone abdominal computed tomography were selected. We evaluated the mean computed tomography values of the pancreas and spleen and then calculated IPFD score. Multiple regression analyses were used to assess the associations between IPFD score and lifestyle factors.

Results

Fast eating speed, late-night eating, and early morning awakening were significantly associated with a high IPFD score after adjusting for age, sex, diabetes status and Body Mass Index (p=0.04, 0.01, 0.01, respectively).

Conclusion

The current study has elucidated the significant associations of fast eating speed, late-night eating, and early morning awakening with IPFD.

Myocardial fat accumulation is associated with cardiac dysfunction in patients with type 2 diabetes, especially in elderly or female patients: a retrospective observational study

BACKGROUND

Ectopic fat is fat that accumulates in or around specific organs or compartments of the body including myocardium. The clinical features of type 2 diabetes patients with high fat accumulation in the myocardium remain unknown. Moreover, little is known about the influence of myocardial fat accumulation in type 2 diabetes on coronary artery disease and cardiac dysfunction. We aimed to clarify the clinical features, including cardiac functions, of type 2 diabetes patients with myocardial fat accumulation.

METHODS

We retrospectively enrolled type 2 diabetes patients who underwent ECG-gated coronary computed tomography angiography (CCTA) and abdominal computed tomography (CT) scan examinations within 1 year of CCTA from January 2000 to March 2021. High fat accumulation in the myocardium was defined as the low mean myocardial CT value of three regions of interest, and the associations between CT values and clinical characteristics or cardiac functions were assessed.

RESULTS

In total, 124 patients were enrolled (72 males and 52 females). The mean age was 66.6 years, the mean BMI was 26.2 kg/m², the mean ejection fraction (EF) was 67.6%, and the mean myocardial CT value was 47.7 Hounsfield unit. A significant positive correlation was found between myocardial CT value and EF (r = 0.3644, p = 0.0004). The multiple regression analyses also showed that myocardial CT value was independently associated with EF (estimate, 0.304; 95% confidence interval (CI) 0.092 to 0.517; p = 0.0056). Myocardial CT value showed significant negative correlations with BMI, visceral fat area and subcutaneous fat area (r = - 0.1923, - 0.2654, and -0.3569, respectively, p < 0.05). In patients who were ≥ 65 years or female, myocardial CT value showed significant positive correlations with not only EF (r = 0.3542 and 0.4085, respectively, p < 0.01) but also early lateral annular tissue Doppler velocity (Lat e') (r = 0.5148 and 0.5361, respectively, p < 0.05). The multiple regression analyses showed that myocardial CT value was independently associated with EF and Lat e' in these subgroups (p < 0.05).

CONCLUSIONS

Patients with type 2 diabetes, especially in elderly or female patients, who had more myocardial fat had more severe left ventricular systolic and diastolic dysfunctions. Reducing myocardial fat accumulation may be a therapeutic target for type 2 diabetes patients.

Clinical Trajectory and Predictors of Intensive Care Unit Mortality Among Nonalcoholic Fatty Liver Disease Patients: A Retrospective Case-Control Study

Background

Despite being the most common liver disease worldwide, the clinical trajectory and inpatient crude mortality rate of nonalcoholic fatty liver disease (NAFLD) patients admitted to the intensive care unit (ICU) have not been thoroughly studied.

Methods

We conducted a single-center retrospective case-control study of patients admitted to a general ICU setting between the years 2015 and 2020. Medical records from patients who met the diagnostic criteria for NAFLD, as well as age- and gender-matched control group, were reviewed. The primary endpoint was crude ICU mortality, defined as death within 30 days of ICU admission. The secondary outcomes included presentation with septic shock and severe sepsis, Sequential Organ Failure Assessment score and Acute Physiology and Chronic Health Evaluation II scores, vasopressor requirements, mechanical ventilation need, and admission-to-ICU transfer time.

Results

Two hundred fifty subjects were enrolled and were equally divided into the NAFLD and control groups. NAFLD group subjects had higher overall 30-day ICU mortality (63.9% vs 36.1%, P < 0.05), more frequent presentation with septic shock and severe sepsis (55.2% vs 33.6%, P < 0.05), higher Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores at presentation (21.3 ± 12.5 vs 16.6 ± 10.5 and 11.36 ± 5.2 vs 8.3 ± 6.2, P < 0.05), higher need for mechanical ventilation (18.4 vs 7.2%, P = 0.05), and vasopressor (15.2% vs 7.2%, P = 0.05) dependency on admission with a shorter admission-to-ICU transfer mean interval (3 vs 6 days, P < 0.05). There were no differences in the need for blood transfusions, steroids, or dialysis between the two groups. Higher fibrosis-4 (FIB-4) and NAFLD fibrosis scores were found to be associated with mortality in ICU-admitted NAFLD patients.

Conclusion

NAFLD patients are more likely than non-NAFLD admitted ICU patients to present with severe sepsis and septic shock, have a shorter admission-to-ICU transfer time, and have a higher crude ICU mortality rate.

Non-invasive imaging biomarkers for liver steatosis in non-alcoholic fatty liver disease: present and future

Non-alcoholic fatty liver disease is currently the most common chronic liver disease, affecting up to 25% of the global population. Simple fatty liver, in which fat is deposited in the liver without fibrosis, has been regarded as a benign disease in the past, but it is now known to be prognostic. In the future, more emphasis should be placed on the quantification of liver fat. Traditionally, fatty liver has been assessed by histological evaluation, which requires an invasive examination; however, technological innovations have made it possible to evaluate fatty liver by non-invasive imaging methods, such as ultrasonography, computed tomography, and magnetic resonance imaging. In addition, quantitative as well as qualitative measurements for the detection of fatty liver have become available. In this review, we summarize the currently used qualitative evaluations of fatty liver and discuss quantitative evaluations that are expected to further develop in the future.

Clinical-radiomic analysis for non-invasive prediction of liver steatosis on non-contrast CT: A pilot study

Purpose: Our aim is to build and validate a clinical-radiomic model for non-invasive liver steatosis prediction based on non-contrast computed tomography (CT). Methods: We retrospectively reviewed 342 patients with suspected NAFLD diagnoses between January 2019 and July 2020 who underwent non-contrast CT and liver biopsy. Radiomics features from hepatic and splenic regions-of-interests (ROIs) were extracted based on abdominal non-contrast CT imaging. The radiomics signature was constructed based on reproducible features by adopting the least absolute shrinkage and selection operator (LASSO) regression. Then, multivariate logistic regression analysis was applied to develop a combined clinical-radiomic nomogram integrating radiomics signature with several independent clinical predictors in a training cohort of 124 patients between January 2019 and December 2019. The performance of models was determined by the area under the receiver operating characteristic curves and calibration curves. We conducted an internal validation during 103 consecutive patients between January 2020 and July 2020. Results: The radiomics signature was composed of four steatosis-related features and positively correlated with pathologic liver steatosis grade (p < 0.01). In both subgroups (Group One, none vs. steatosis; Group Two, none/mild vs. moderate/severe steatosis), the clinical-radiomic model performed best within the validation cohort with an AUC of 0.734 and 0.930, respectively. The calibration curve confirmed the concordance of excellent models. Conclusion: We developed a robust clinical-radiomic model for accurate liver steatosis stage prediction in a non-invasive way, which may improve the clinical decision-making ability.

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.

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.

Dual-Energy Computed Tomography in Diffuse Liver Diseases

Dual-energy computed tomography (DECT) is an advancement in the field of CT, where images are acquired at two energies. Materials are identified and quantified based on their attenuation pattern at two different energy beams using various material decomposition algorithms. With its ability to identify and quantify materials such as fat, calcium, iron, and iodine, DECT adds great value to conventional CT and has innumerable applications in body imaging. Continuous technological advances in CT scanner hardware, material decomposition algorithms, and image reconstruction software have led to considerable growth of these applications. Among all organs, the liver is the most widely investigated by DECT, and DECT has shown promising results in most liver applications. In this article, we aim to provide an overview of the role of DECT in the assessment of diffuse liver diseases, mainly the deposition of fat, fibrosis, and iron and review the most relevant literature.

Fatty liver on computed tomography scan on admission is a risk factor for severe coronavirus disease

OBJECTIVES

To alleviate the overflow of coronavirus disease 2019 (COVID-19) patients in hospitals, less invasive and simple criteria are required to triage the patients. We evaluated the relationship between COVID-19 severity and fatty liver on plain computed tomography (CT) scan performed on admission.

METHODS

In this retrospective cohort study, we considered all COVID-19 patients at a large tertiary care hospital between January 31 and August 31, 2020. COVID-19 severity was categorized into severe (moderate and severe) and non-severe (asymptomatic and mild) groups, based on the Japanese National COVID-19 guidelines. Fatty liver was detected on plain CT scan. Multivariate logistic regression analysis was performed to evaluate factors associated with severe COVID-19.

RESULTS

Of 222 patients (median age: 52 years), 3.2%, 58.1%, 20.7%, and 18.0% presented with asymptomatic, mild, moderate, and severe COVID-19, respectively. Although 59.9% had no fatty liver on plain CT, mild, moderate, and severe fatty liver occurred in 13.1%, 18.9%, and 8.1%, respectively. Age and presence of fatty liver were significantly associated with severe COVID-19.

CONCLUSION

Our study showed that fatty liver on plain CT scan on admission can become a risk factor for severe COVID-19. This finding may help clinicians to easily triage COVID-19 patients.

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.

Virtual noncontrast images derived from dual-energy CT for assessment of hepatic steatosis in living liver donors

PURPOSE

This study aimed to investigate the correlation of attenuation between virtual noncontrast (VNC) and true noncontrast (TNC) CT images and compare the diagnostic performance for hepatic steatosis using MR spectroscopy (MRS) as the reference standard.

METHODS

A total of 131 consecutive hepatic donor candidates who underwent dual-source dual-energy CT and MRS within one month from January 2018 to April 2019 were included. An MRS value > 5.8 % was regarded as substantial hepatic steatosis. The correlation of attenuation between TNC and VNC in the liver and spleen, and liver attenuation index (LAI), defined as hepatic minus splenic attenuation, was evaluated using Spearman's rank correlation. The diagnostic performance of the LAI for hepatic steatosis was compared using receiver operating characteristic analyses.

RESULTS

Twenty-three candidates (17.6 %) had substantial hepatic steatosis. The median liver attenuation (66.7 [IQR, 63.5-70.9] vs. 63.5 [IQR, 60.3-66.9], p < .001) and LAI (12.9 [9.3-16.7] vs. 7.4 [3.9-11.9], p < .001) in the VNC were higher than those in the TNC. Hepatic attenuation (r = 0.93, p < .001), splenic attenuation (r = 0.55, p < .001), and LAI (r = 0.87, p < .001) were significantly correlated between TNC and VNC. Area under the curve of LAI in TNC and VNC were 0.88 (cutoff, LAI < 3.1) and 0.84 (cutoff, LAI < 10.1), respectively, indicating no statistically significant difference (p = 0.11).

CONCLUSION

The LAI of VNC is significantly correlated with that of TNC and might be feasible for diagnosing substantial hepatic steatosis in living liver donor candidates using different cutoff values of LAI.

Baseline liver steatosis has no impact on liver metastases and overall survival in rectal cancer patients

Background

The liver is one of the most frequent sites of metastases in rectal cancer. This study aimed to evaluate how the development of synchronous or metachronous liver metastasis and overall survival are impacted by baseline liver steatosis and chemotherapy-induced liver damage in rectal cancer patients.

Methods

Patients diagnosed with stage II to IV rectal cancer between 2010 and 2016 in our province with suitable baseline CT scan were included. Data on cancer diagnosis, staging, therapy, outcomes and liver function were collected. CT scans were retrospectively reviewed to assess baseline steatosis (liver density < 48 HU and/or liver-to-spleen ratio < 1.1). Among patients without baseline steatosis and treated with neoadjuvant chemotherapy, chemotherapy-induced liver damage was defined as steatosis appearance, ≥ 10% liver volume increase, or significant increase in liver function tests.

Results

We included 283 stage II to IV rectal cancer patients with suitable CT scan (41% females; mean age 68 ± 14 years). Steatosis was present at baseline in 90 (31.8%) patients, synchronous liver metastasis in 42 (15%) patients and metachronous liver metastasis in 26 (11%); 152 (54%) deaths were registered. The prevalence of synchronous liver metastasis was higher in patients with steatosis (19% vs 13%), while the incidence of metachronous liver metastasis was similar. After correcting for age, sex, stage, and year of diagnosis, steatosis was not associated with metachronous liver metastasis nor with overall survival. In a small analysis of 63 patients without baseline steatosis and treated with neoadjuvant chemotherapy, chemotherapy-induced liver damage was associated with higher incidence of metachronous liver metastasis and worse survival, results which need to be confirmed by larger studies.

Conclusions

Our data suggest that rectal cancer patients with steatosis had a similar occurrence of metastases during follow-up, even if the burden of liver metastases at diagnosis was slightly higher, compatible with chance.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-07980-9.

The effect of hepatic steatosis on COVID-19 severity: Chest computed tomography findings

BACKGROUND

The objective of our study was to investigate the location, extension and type of novel coronavirus-induced disease 2019 (COVID-19) infection involvement and hepatic steatosis on initial chest computed tomography (CT). The relationship between fatty liver and severity of the disease was also investigated by measuring the liver attenuation index (LAI).

METHODS

This study evaluated the chest CT images of 343 patients (201 male, mean age 48.43 years) who were confirmed to have COVID-19, using nasopharyngeal swab. The chest CTs were analyzed for laterality, number of involved lobes, diffuseness, number of lesions, and lesion types. The CT attenuation values of liver and spleen were measured, and LAI was calculated for the detection of hepatic steatosis. Univariate and multivariate logistic regression analysis were used to identify the independent early predictors for severe COVID-19.

RESULTS

There was no significant difference between genders in terms of clinical course. Liver density and LAI were significantly lower in the intensive care unit (ICU) patients. The prevalence of severe disease was higher in the patients with hepatic steatosis than in the non-steatotic group (odds ratio [OR] 3.815, 95% confidence interval [CI] 1.97-7.37, P < 0.001). After adjusting for age and comorbidities including hypertension, diabetes mellitus, coronary artery disease, chronic obstructive pulmonary disease, and chronic kidney disease, multivariate logistic regression analysis showed that non-alcoholic fatty liver disease (NAFLD) was an independent risk factor for COVID-19 severity (OR 3.935, 95% CI 1.77-8.70, P = 0.001). The optimal cut-off value for LAI was calculated as 0.5 for predicting patients who required ICU treatment.

CONCLUSIONS

On the initial chest CT images of COVID-19 patients, presence of fatty liver is a strong predictor for severe disease.

Utility of Multiparametric CT for Identification of High-Risk NAFLD

OBJECTIVE. The purpose of this study was to evaluate the utility of laboratory and CT metrics in identifying patients with high-risk nonalcoholic fatty liver disease (NAFLD). MATERIALS AND METHODS. Patients with biopsy-proven NAFLD who underwent CT within 1 year of biopsy were included. Histopathologic review was performed by an experienced gastrointestinal pathologist to determine steatosis, inflammation, and fibrosis. The presence of any lobular inflammation and hepatocyte ballooning was categorized as nonalcoholic steatohepatitis (NASH). Patients with NAFLD and advanced fibrosis (stage F3 or higher) were categorized as having high-risk NAFLD. Aspartate transaminase to platelet ratio index and Fibrosis-4 (FIB-4) laboratory scores were calculated. CT metrics included hepatic attenuation, liver segmental volume ratio (LSVR), splenic volume, liver surface nodularity score, and selected texture features. In addition, two readers subjectively assessed the presence of NASH (present or not present) and fibrosis (stages F0-F4). RESULTS. A total of 186 patients with NAFLD (mean age, 49 years; 74 men and 112 women) were included. Of these, 87 (47%) had NASH and 112 (60%) had moderate to severe steatosis. A total of 51 patients were classified as fibrosis stage F0, 42 as F1, 23 as F2, 37 as F3, and 33 as F4. Additionally, 70 (38%) had advanced fibrosis (stage F3 or F4) and were considered to have high-risk NAFLD. FIB-4 score correlated with fibrosis (ROC AUC of 0.75 for identifying high-risk NAFLD). Of the individual CT parameters, LSVR and splenic volume performed best (AUC of 0.69 for both for detecting high-risk NAFLD). Subjective reader assessment performed best among all parameters (AUCs of 0.78 for reader 1 and 0.79 for reader 2 for detecting high-risk NAFLD). FIB-4 and subjective scores were complementary (combined AUC of 0.82 for detecting high-risk NAFLD). For NASH assessment, FIB-4 performed best (AUC of 0.68), whereas the AUCs were less than 0.60 for all individual CT features and subjective assessments. CONCLUSION. FIB-4 and multiple CT findings can identify patients with high-risk NAFLD (advanced fibrosis or cirrhosis). However, the presence of NASH is elusive on CT.

Hepatic Steatosis Index in the Detection of Fatty Liver in Patients with Chronic Hepatitis B Receiving Antiviral Therapy

Background/Aims

The hepatic steatosis index (HSI) is a noninvasive method to assess the severity of hepatic steatosis. Antiviral therapy (AVT) can impact aspartate aminotransferase and alanine aminotransferase levels, which are the main components of the HSI. Thus, we investigated the accuracy of the HSI in detecting hepatic steatosis in patients with chronic hepatitis B (CHB) receiving AVT, compared with those not receiving AVT and in those with nonalcoholic fatty liver disease (NAFLD).

Methods

Patients with CHB or NAFLD who underwent a magnetic resonance imaging proton density fat fraction (MRI-PDFF) evaluation between March 2010 and March 2019 were recruited. Hepatic steatosis was diagnosed when the PDFF exceeded 5%. Area under the receiver operating characteristic curve (AUROC) analysis was used to assess the diagnostic accuracy of the HSI in the detection of hepatic steatosis.

Results

The mean age of the study population (189 men and 116 women; 244 with CHB [184 with and 60 without AVT] and 61 with NAFLD) was 55.6 years. The AUROC values for detecting hepatic steatosis were similar between patients with CHB (0.727; p<0.001) and those with NAFLD (0.739; p=0.002). However, when patients with CHB were subdivided into those receiving and not receiving AVT, the AUROC value decreased slightly in patients with CHB receiving AVT compared to those without not receiving AVT (0.707; p=0.001 vs 0.779; p=0.001).

Conclusions

Despite a slight attenuation, the diagnostic accuracy of the HSI in patients with CHB receiving AVT in detecting hepatic steatosis was still acceptable. Further large-scale studies are required for validation.

CT and MR imaging evaluation of living liver donors

Preoperative cross-sectional imaging evaluation of potential living liver donors allows to exclude donors with an increased risk for morbidity and mortality, and to assure that a suitable graft for the recipient can be obtained, minimizing the risk of complications in both the donor and the recipient. CT is routinely performed to delineate the anatomy of the liver, relevant vasculature, and liver volumes in whole right or left lateral segment donation. MR imaging is the gold standard for the assessment of biliary anatomy and allows a better quantification of hepatic steatosis compared to CT. Knowledge of normal and variant vascular and biliary anatomy and their surgical relevance for liver transplantation is of paramount importance for the radiologist. The purpose of this review is to outline the current role of CT and MR imaging in the assessment of hepatic parenchyma, hepatic vascular anatomy, biliary anatomy, and hepatic volumetry in the potential living liver donor with short notes on acquisition protocols and the relevant reportable findings.

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.

Radiologic Nonalcoholic Fatty Liver Disease Increases the Risk of Hepatocellular Carcinoma in Patients With Suppressed Chronic Hepatitis B

BACKGROUND AND GOALS

Although nonalcoholic fatty liver disease (NAFLD) is a risk factor of hepatocellular carcinoma (HCC), it is unclear whether NAFLD additionally increases the risk of HCC among chronic hepatitis B (CHB) patients. This study evaluated the association between NAFLD and the risk of HCC in patients whose hepatitis B virus (HBV) was well controlled.

STUDY

This study included consecutive CHB patients whose serum HBV DNA levels were continuously suppressed <2000 IU/mL with antiviral treatment. Fatty liver was radiologically diagnosed. Patients with concomitant hepatitis C infection, autoimmune hepatitis, or excessive alcohol use were excluded.

RESULTS

Among 826 patients, 86 patients (10.4%) developed HCC during the study period (median, 43.1 mo). The patients with NAFLD (N=260) had a significantly higher risk for HCC compared with patients without NAFLD (N=566) (adjusted hazard ratio, 1.67; 95% confidence interval, 1.05-2.63; P=0.03) after adjustment for age, the presence of cirrhosis, hepatitis B envelop antigen positivity, low-level viremia and hypertension. There was significant association between incomplete biochemical response (IBR) (alanine aminotransferase levels ≥40 IU/L) and the presence of NAFLD (P<0.001 by χ test). IBR at the time of virological response was associated with a significantly higher risk of HCC development (adjusted hazard ratio, 1.63; 95% confidence interval, 1.06-2.54; P=0.03).

CONCLUSIONS

NAFLD increases the risk of HCC in patients with CHB in whom HBV is effectively suppressed by antivirals. Patients with IBR should be suspected of concurrent NAFLD. Further study is warranted to evaluate whether improvement of NAFLD might decrease the risk of HCC development.

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

Background

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

Main text

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

Conclusions

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

Lifestyle Modification Leads to Spatially Variable Reduction in Hepatic Steatosis in Potential Living Liver Donors

The spatial variability of hepatic fat reduction in potential living liver donors with hepatic steatosis (HS) who undergo lifestyle modification has not been investigated. Here, we aimed to examine the intrasegmental and intersegmental variability of changes in liver attenuation on computed tomography (CT) in potential living liver donors with HS after diet modification and exercise. A total of 87 living liver donor candidates (30.5 ± 7.0 years; 74 males) with biopsy-proven macrovesicular fat (MaF) ≥10% were included. All underwent diet modification and exercise to improve HS, baseline and follow-up unenhanced CT scans, and liver biopsies. Attenuation and its variability (mean and standard deviation, respectively, in Hounsfield units) in segmental, lobar, superficial, deep, and whole areas of the liver were measured across 32 different regions of interest on both baseline and follow-up CT. At baseline, the right lobe and superficial areas of liver showed significantly lower and more variable attenuation than left lobe and deep areas. Greater variability was noted in patients with more severe HS. Mean interval changes in liver attenuation and variability before and after diet modification and exercise were 13.7 (range, -10.6 to 46.2) and 4.7 (1.6-10.6), respectively. The mean interval change in liver attenuation was significantly higher in the right lobe than in the left (14.7 versus 12.7; P < 0.001), and in superficial areas than in deep areas (14.0 versus 13.4; P = 0.02). Greater variability and larger interval changes in liver attenuation were noted in those who responded (≥20% decrease in MaF) to diet modification and exercise than in those who did not. In conclusion, potential living liver donors with HS show significant intrasegmental and intersegmental variability in hepatic fat reduction on CT before and after diet modification and exercise.

Multiparametric MR Index for the Diagnosis of Non-Alcoholic Steatohepatitis in Patients with Non-Alcoholic Fatty Liver Disease

Non-alcoholic steatohepatitis (NASH) is a complex disease consisting of various components including steatosis, lobular inflammation, and ballooning degeneration, with or without fibrosis. Therefore, it is difficult to diagnose NASH with only one imaging modality. This study was aimed to evaluate the feasibility of magnetic resonance imaging (MRI) for predicting NASH and to develop a non-invasive multiparametric MR index for the detection of NASH in non-alcoholic fatty liver disease (NAFLD) patients. This prospective study included 47 NAFLD patients who were scheduled to undergo or underwent ultrasound-guided liver biopsy within 2 months. Biopsy specimens were graded as NASH or non-NASH. All patients underwent non-enhanced MRI including MR spectroscopy (MRS), MR elastography (MRE), and T1 mapping. Diagnostic performances of MRS, MRE, and T1 mapping for grading steatosis, activity, and fibrosis were evaluated. A multiparametric MR index combining fat fraction (FF), liver stiffness (LS) value, and T1 relaxation time was developed using linear regression analysis. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of the newly devised MR index. Twenty NASH patients and 27 non-NASH patients were included. Using MRS, MRE, and T1 mapping, the mean areas under the curve (AUCs) for grading steatosis, fibrosis, and activity were 0.870, 0.951, and 0.664, respectively. The multiparametric MR index was determined as 0.037 × FF (%) + 1.4 × LS value (kPa) + 0.004 × T1 relaxation time (msec) −3.819. ROC curve analysis of the MR index revealed an AUC of 0.883. The cut-off value of 6 had a sensitivity of 80.0% and specificity of 85.2%. The multiparametric MR index combining FF, LS value, and T1 relaxation time showed high diagnostic performance for detecting NASH in NAFLD patients.

Computed Tomography Measurements of Hepatic Steatosis in Cholelitihiasis and Cholecystectomy Cases Using Unenhanced Images

INTRODUCTION

Computed tomography (CT) measurements of hepatic steatosis can be performed using unenhanced CT images. The purpose of this study was to assess the occurrence of hepatic steatosis using unenhanced CT images for patients undergoing cholecystectomy or having cholelithiasis.

METHODS

A total of 143 unenhanced CT cases from a single centre were retrospectively examined. The CT number of liver, ratio of CT number of liver to spleen, and CT number of liver minus CT number of spleen were measured in three groups: (1) patients undergoing cholecystectomy, (2) patients having cholelithiasis, and (3) control group. Abdominal circumference, anterior subcutaneous fat tissue thickness, and body mass index were obtained.

RESULTS

Mean CT number of liver was significantly different between the group of patients with cholecystectomy and cholelithiasis and the control group (P < .001) and also between cases of cholecystectomy and cholelithiasis (P = .041), with the lowest CT number of liver in the cholecystectomy group. The mean CT number of liver minus CT number of spleen and mean CT number (liver/spleen) ratios, evaluated separately for both lobes, were not different comparing the cholelithiasis and cholecystectomy groups. The mean CT number of liver minus CT number of spleen and mean CT number (liver/spleen) ratios differed significantly between the control group and both patient groups (P < .001). Positive correlations were identified between abdominal circumference, subcutaneous fat depth, body mass index, and liver size and hepatic steatosis.

CONCLUSION

There was an increased occurrence of hepatic steatosis in patients who have undergone a cholecystectomy compared with patients treated for cholelithiasis and the control group.

Pancreatic fat is related to the longitudinal decrease in the increment of C-peptide in glucagon stimulation test in type 2 diabetes patients

AIMS/INTRODUCTION

The relationship between pancreatic fatty infiltration and diabetes is widely known, whereas the causal relationship is not clear. Furthermore, it is uncertain whether pathogenesis of pancreatic fat is similar to that of liver fat. We aimed to clarify the contribution of this type of fat to glucose metabolism in type 2 diabetes patients by cross-sectional and longitudinal analyses.

MATERIAL AND METHODS

A total of 56 patients with type 2 diabetes who had been hospitalized twice were analyzed. We evaluated the mean computed tomography values of the pancreas (P), liver (L) and spleen (S). Lower computed tomography values indicate a greater fat content. We defined indices of pancreatic or liver fat content as the differences between P or L and S. We assessed the associations among fat content for the two organs (P-S, L-S) and clinical parameters at the first hospitalization, and then analyzed the associations between these fat contents and changes in glycometabolic markers (the second data values minus the first).

RESULTS

In the cross-sectional study, P-S negatively correlated with the increment of C-peptide in the glucagon stimulation test (r = -0.71, P < 0.0001) and body mass index (r = -0.28, P = 0.034). L-S negatively correlated with homeostasis model assessment of insulin resistance (r = -0.73, P < 0.0001), body mass index (r = -0.62, P < 0.0001) and some other obesity-related indicators, but not with the increment of C-peptide in the glucagon stimulation test. In the longitudinal study, P-S positively correlated with the change of the increment of C-peptide in the glucagon stimulation test (r = 0.49, P = 0.021).

CONCLUSIONS

In type 2 diabetes patients, pancreatic fat was less associated with obesity-related indicators than liver fat, but was more strongly associated with the longitudinal decrease in endogenous insulin-secreting capacity.

Utility of magnetic resonance proton density fat fraction technique in quantification of liver fat in living donors for liver transplantation

Background

Hepatic steatosis in living donors for liver transplantation causes morbidity of both donor and recipient. This study aims at evaluating magnetic resonance proton density fat fraction technique (MR PDFF) in quantitative evaluation of living donor’s hepatic steatosis compared to histopathology.

Results

The examined potential living liver donors’ liver biopsies revealed hepatic steatosis < 5% (grade 0) in 40 donors and 5–10% (grade 1) in 7 donors. MR PDFF technique with IDEAL sequence showed excellent results for prediction and quantitative evaluation of liver fat with sensitivity, specificity, and accuracy of 85.7%, 97.5%, and 95.7%, respectively, compared to histopathology (95% confidence interval 0.98–1.01). There was an excellent inter-reader agreement between both readers in estimation of MR liver fat fraction (r = 0.969 at 95% confidence interval 0.946–0.983).

Conclusion

Noninvasive hepatic MR PDFF technique with IDEAL sequence is a precise reliable technique for pre-operative quantitative assessment of hepatic steatosis in potential living liver donors.

Is Unenhanced Computed Tomography Reliable in the Assessment of Macrovesicular Steatosis in Living Liver Donors?

OBJECTIVES

In this retrospective study, we aimed to determine the diagnostic value of unenhanced computed tomography in the assessment of macrovesicular steatosis in potential living liver transplant donors by using biopsy as a reference standard.

MATERIALS AND METHODS

This retrospective study was approved by our institutional review board, and all included patients provided written informed consent. Our study group included 181 donor candidates (mean age of 35.9 ± 9.3 y) who underwent unenhanced computed tomography and subsequent needle biopsy (mean period after scan of 12.74 d) in the right hepatic lobe (at least 2 samples per patient). Histologic degree of macrovesicular steatosis was determined. A radiologist with 10 years of experience assessed steatosis ofthe right hepatic lobe by using 2 methods: (1) a 4-point visual grading system that used attenuation comparison between the liver and hepatic vessels and (2) the liver attenuation index, which was calculated with region of interest measurements of hepatic attenuation. We used statistical analyses to compare accuracy in the diagnosis of macrovesicular steatosis.

RESULTS

Our study population was divided into 3 groups according to histologic steatosis grade. Group 1 consisted of 157 candidates with 0% to 5% steatosis, group 2 consisted of 11 candidates with 6% to 15% steatosis, and group 3 consisted of 13 candidates with 16% to 100% steatosis. Mean liver attenuation (in Hounsfield units ± standard deviation) was 58.93 ± 5.07 for group 1, 47.8 ± 4.17 for group 2, and 39.11 ± 6.5 for group 3. Significant differences in liver attenuation were observed between groups using one-way analyses of variance (F = 107307; P < .01). For visual grading, correlation coefficient for computed tomography was 0.959.

CONCLUSIONS

Unenhanced computed tomography to assess liver attenuation represents an objective and noninvasive means for detection of hepatic steatosis. This method can prevent unnecessary biopsies.

Comparison of CT methods for determining graft steatosis in living donor liver transplantation

PURPOSE

To evaluate and compare the diagnostic performance of non-enhanced computed tomography (NECT) and contrast-enhanced CT (CECT) attenuation indices in the assessment of hepatic steatosis by using biopsy as the reference standard.

MATERIALS AND METHODS

This retrospective study was approved by our Institutional Review Board. 55 Potential donors who underwent both NECT and triphasic CECT and core liver biopsy, were included the study. Average attenuation measurements that were obtained from multiple regions in liver, spleen, and psoas muscle on both unenhanced and CECT were used for analysis. Hepatic attenuation measurements were analyzed with and without normalization with the spleen and psoas muscle. Linear regression and receiver operating characteristic (ROC) curve analysis were used to evaluate the statistical association between CT indices and steatosis at histology.

RESULTS

Linear regression analysis confirmed the strongest correlation between steatosis and normalized measurements of hepatic attenuation with splenic attenuations on hepatic venous phase of CECT scan (R 0.821; R² 0.674 and R 0.816; R² 0.665, respectively). The use of ROC curve analysis also demonstrated that normalized measurements of hepatic attenuation with splenic attenuations on hepatic venous phase of CECT showed high diagnostic performance regarding the qualitative distinction of steatosis (AUC values greater than 0.9).

CONCLUSION

Attenuation measurements of liver normalized with spleen on hepatic venous phase may be useful in evaluating steatosis in donor candidates with moderate to severe steatosis who are unacceptable for liver donation. In this manner unnecessary liver biopsy may be avoided in those donor candidates.

Evaluation on Heterogeneity of Fatty Liver in Rats: A Multiparameter Quantitative Analysis by Dual Energy CT

RATIONALE AND OBJECTIVES

To investigate the value of using rapid kVp switching dual energy computed tomography (rsDECT) for the multi-parameter analysis of the heterogeneity of fatty liver in rat.

MATERIALS AND METHODS

Twenty-four male rats were randomly divided into experimental (n = 16) and control (n = 8) groups. Four rats in the experimental group and two in the control group were examined by rsDECT every 3 weeks starting from week 8. The liver fat contents (LFC) of the left and right liver lobes were measured on the fat(water)-based material decomposition images to calculate fat content and CT value of liver and spleen were measured on the 70keV monochromatic images to calculate the liver-to-spleen CT value ratio [(L/S)_70 keV] and difference at 70keV[(L-S)_70 keV], and the spectral curve slopes of the left and right liver lobes (Slope-L, Slope-R). Measurements were evaluated statistically.

RESULTS

The statistical analysis showed that the (L/S)_70 keV, (L-S)_70 keV, Slope and LFC in the different fatty liver groups were all significantly different (p < 0.05). Pearson correlation analysis results showed that the rsDECT results of the left and right liver lobes correlated with the fat percentage from pathological analysis (p < 0.05), with the left liver lobe having better correlation. Paired t-tests showed that the fat percentage of the left liver lobe was significantly higher than that of the right one, while (L/S)_70 keV, and (L-S)_70 keV were significantly lower. Diagnostic analysis using ROC curve showed that the areas under the curves with parameters of the left liver lobe were also greater than those of the right liver lobe.

CONCLUSION

rsDECT multi-parameter imaging could quantitatively evaluate the heterogeneity of fat deposition in the liver, providing valuable information for the accurate and effective assessment of the heterogeneity of fatty liver.

Feasibility of non-enhanced CT for assessing longitudinal changes in hepatic steatosis

To evaluate the feasibility of computed tomography (CT) in the assessment of the change in hepatic steatosis (HS) in longitudinal follow-up by employing pathological HS as the reference standard.We retrospectively evaluated 38 living liver donor candidates (27 men and 11 women; mean age, 29.5 years) who underwent liver biopsy twice and had liver CT scans within 1 week of each biopsy. Four readers independently calculated CTL-S index by subtracting spleen attenuation from liver attenuation on non-enhanced CT images. The changes in pathological HS (ΔHS) and CTL-S (ΔCTL-S) between the 1st and 2nd examinations were assessed. The correlation between ΔHS and ΔCTL-S was assessed using the linear regression analysis. Inter-observer measurement error for ΔCTL-S among the 4 readers was assessed using the repeatability coefficient.ΔCTL-S showed a significant correlation with ΔHS in all readers (r = 0.571-0.65, P < .001). The inter-observer measurement error for ΔCTL-S was ±8.9. The ΔCTL-S values beyond the measurement error were associated with a consistent change in HS in 83.3% (13/15) to 100% (15/15), with sensitivities of 47.8 to 79.9% and specificities of 86.7 to 100% for detecting an absolute change of ≥10% in HS among the 4 readers. However, ΔCTL-S values within the measurement error were associated with a consistent change in HS in 43.5% (8/19) to 61.5% (16/26).The change in CTL-S roughly reflects the change in HS during longitudinal follow-up. A small change in CTL-S should not be considered meaningful, while a larger change in CTL-S beyond the measurement error strongly indicates a true change in HS.

Incidental hepatic steatosis on unenhanced computed tomography performed for suspected renal colic: Gaps in reporting and documentation

INTRODUCTION

Hepatic steatosis is a common incidental finding on computed tomography (CT) in patients presenting to the emergency department (ED). The aims of our study were to assess the prevalence of hepatic steatosis in ED patients with suspected renal colic and to assess documentation in radiology reports and medical charts correlated with alanine transaminase (ALT) levels.

METHODS

Over 18 months from January 2016 to June 2017, all unenhanced CTs performed for suspected renal colic were reviewed. Quantitative assessment measuring hepatic and splenic attenuation in Hounsfield Units was performed. Hepatic steatosis was defined using multiple CT criteria including liver/spleen (L/S) ratio. Radiology reports, medical charts and ALT levels, if collected within 24 h of CT, were reviewed.

RESULTS

A total of 1290 patients were included with a median age 52.5 years (range 16-98) and male predominance (835 [64.7%]). A total of 336 (26%) patients had hepatic steatosis measured by L/S ratio of ≤ 1.0. Ninety-four patients (28%) had radiology reports noting steatosis. Documentation in medical charts was noted in 18 of the 94 patients (19.1%) for whom steatosis was reported. Liver enzymes were available for 704 (54.6%) patients. There was a significantly higher mean ALT level in patients with hepatic steatosis (42.2 U/L; 95% CI 38.4-46.0) compared to patients without (28.8 U/L; 95% CI 25.7-31.9) (P < 0.0001).

CONCLUSION

Our findings highlight multiple gaps in the reporting and evaluation of hepatic steatosis among radiologists and emergency clinicians alike. Recognising and reporting this incidental finding may impact health outcomes.

Liver fat imaging-a clinical overview of ultrasound, CT, and MR imaging

Hepatic steatosis is a frequently encountered imaging finding that may indicate chronic liver disease, the most common of which is non-alcoholic fatty liver disease. Non-alcoholic fatty liver disease is implicated in the development of systemic diseases and its progressive phenotype, non-alcoholic steatohepatitis, leads to increased liver-specific morbidity and mortality. With the rising obesity epidemic and advent of novel therapeutics aimed at altering metabolism, there is a growing need to quantify and monitor liver steatosis. Imaging methods for assessing steatosis range from simple and qualitative to complex and highly accurate metrics. Ultrasound may be appropriate in some clinical instances as a screening modality to identify the presence of abnormal liver morphology. However, it lacks sufficient specificity and sensitivity to constitute a diagnostic modality for instigating and monitoring therapy. Newer ultrasound techniques such as quantitative ultrasound show promise in turning qualitative assessment of steatosis on conventional ultrasound into quantitative measurements. Conventional unenhanced CT is capable of detecting and quantifying moderate to severe steatosis but is inaccurate at diagnosing mild steatosis and involves the use of radiation. Newer CT techniques, like dual energy CT, show potential in expanding the role of CT in quantifying steatosis. MRI proton-density fat fraction is currently the most accurate and precise imaging biomarker to quantify liver steatosis. As such, proton-density fat fraction is the most appropriate noninvasive end point for steatosis reduction in clinical trials and therapy response assessment.

Studying non-alcoholic fatty liver disease: the ins and outs of in vivo, ex vivo and in vitro human models

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing. Determining the pathogenesis and pathophysiology of human NAFLD will allow for evidence-based prevention strategies, and more targeted mechanistic investigations. Various in vivo, ex situ and in vitro models may be utilised to study NAFLD; but all come with their own specific caveats. Here, we review the human-based models and discuss their advantages and limitations in regards to studying the development and progression of NAFLD. Overall, in vivo whole-body human studies are advantageous in that they allow for investigation within the physiological setting, however, limited accessibility to the liver makes direct investigations challenging. Non-invasive imaging techniques are able to somewhat overcome this challenge, whilst the use of stable-isotope tracers enables mechanistic insight to be obtained. Recent technological advances (i.e. normothermic machine perfusion) have opened new opportunities to investigate whole-organ metabolism, thus ex situ livers can be investigated directly. Therefore, investigations that cannot be performed in vivo in humans have the potential to be undertaken. In vitro models offer the ability to perform investigations at a cellular level, aiding in elucidating the molecular mechanisms of NAFLD. However, a number of current models do not closely resemble the human condition and work is ongoing to optimise culturing parameters in order to recapitulate this. In summary, no single model currently provides insight into the development, pathophysiology and progression across the NAFLD spectrum, each experimental model has limitations, which need to be taken into consideration to ensure appropriate conclusions and extrapolation of findings are made.

Grading fatty liver by ultrasound time-domain radiofrequency signal analysis: an in vivo study of rats

This study aimed to assess the severity of fatty liver (FL) by analyzing ultrasound radiofrequency (RF) signals in rats. One hundred and twenty rats (72 in the FL group and 48 in the control group) were used for this purpose. Histological results were the golden standard: 42 cases had normal livers (N), 30 cases had mild FL (L1), 25 cases had moderate FL (L2), 13 cases presented with severe FL (L3), and 10 cases were excluded from the study. Four RF parameters (Mean, Mean/SD ratio [MSR], skewness [SK], and kurtosis [KU] were extracted. Univariate analysis, spearman correlation analysis, and stepwise regression analysis were used to select the most powerful predictors. Receiver operating characteristic (ROC) analysis was used to compare the diagnostic efficacy of single indexes with a combined index (Y) expressed by a regression equation. Mean, MSR, SK, and KU were significantly correlated with FL grades (r=0.71, P<0.001; r=0.81, P<0.001; r=−0.79, P<0.001; and r=−0.74, P<0.001). The regression equation was Y=−4.48 + 3.20 × 10⁻²X1 + 3.15X2 (P<0.001), where Y=hepatic steatosis grade, X1 =Mean, and X2 =MSR. ROC analysis showed that the curve areas of the combined index (Y) were superior to simple indexes (Mean, MSR, SK, and KU) in evaluating hepatic steatosis grade, and they were 0.95 (L≥L1), 0.98 (L≥L2), and 0.99 (L≥L3). Ultrasound radiofrequency signal quantitative technology was a new, noninvasive, and promising sonography-based approach for the assessment of FL.

Adult-to-adult living donor liver transplantation preoperative survey using MDCT, a single medical center experience in Taiwan

This study evaluated multi-detector computed tomography (MDCT) scans performed on potential living donors for adult-to-adult liver transplantation (LDLT), with the aim of identifying significant findings that could be used to exclude potential transplantation donors. We retrospectively reviewed the medical records of 151 consecutive potential adult donors for LDLT from May 2007 to January 2015. Liver parenchyma steatosis, focal hepatic mass or intraabdominal malignancy, vascular variations, and donor liver volume were evaluated via MDCT. Grounds for excluding potential donors were also recorded and analyzed. Of the 151 potential donors, nine (6.0%) had moderate to severe fatty liver, 37 (24.5%) had hepatic arterial variants, 22 (14.6%) had significant portal venous variants, and more than half were found to have right accessory inferior hepatic vein. No intraabdominal malignancies were found. Eighty-eight potential donors were rejected, with the most common cause being insufficient recipient volume or remnant donor volume (47.7%), moderate to severe parenchymal steatosis (10.2%), and recipient expiration prior to transplantation (8.0%). An additional 16 potential donors were excluded by the surgical team due to the complexity of their portal venous variations. The rate of exclusion by pre-transplant imaging evaluation with MDCT was 33.8%. MDCT can provide accurate quantification of donor liver volume and steatosis severity along with precise demonstration of vascular variants, which are crucial for the preoperative evaluation of LDLT. However, MDCT may be ineffective for evaluating the biliary system without hepatobiliary-excreted contrast agent and has the disadvantage of ionizing radiation.

Radiologic Imaging in Nonalcoholic Fatty Liver Disease and Nonalcoholic Steatohepatitis

The article reviews the multimodality (ultrasound, computed tomography, and magnetic resonance [MR]) imaging appearance of nonalcoholic fatty liver disease (NAFLD) and discusses the radiologic diagnostic criteria as well as the sensitivity and specificity of these imaging methods. The authors review the role of both ultrasound and MR elastography for the diagnosis of fibrosis and for the longitudinal evaluation of patients following therapeutic intervention. Lastly, the authors briefly discuss the screening and diagnosis of hepatocellular carcinoma in patients with NAFLD, as there are special considerations in this population.

Assessing the Non-tumorous Liver: Implications for Patient Management and Surgical Therapy

INTRODUCTION

Hepatic resection is performed for various benign and malignant liver tumors. Over the last several decades, there have been improvements in the surgical technique and postoperative care of patients undergoing liver surgery. Despite this, liver failure following an extended hepatic resection remains a critical potential postoperative complication. Patients with underlying parenchymal liver diseases are at particular risk of liver failure due to impaired liver regeneration with an associated mortality risk as high as 60 to 90%. In addition, live donor liver transplantation requires a thorough presurgical assessment of the donor liver to minimize the risk of postoperative complications.

RESULTS AND CONCLUSION

Recently, cross-sectional imaging assessment of diffuse liver diseases has gained momentum due to its ability to provide both anatomical and functional assessments of normal and abnormal tissues. Various imaging techniques are being employed to assess diffuse liver diseases including magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound (US). MRI has the ability to detect abnormal intracellular and molecular processes and tissue architecture. CT has a high spatial resolution, while US provides real-time imaging, is inexpensive, and readily available. We herein review current state-of-the-art techniques to assess the underlying non-tumorous liver. Specifically, we summarize current approaches to evaluating diffuse liver diseases including fatty liver alcoholic or non-alcoholic (NAFLD, AFLD), hepatic fibrosis (HF), and iron deposition (ID) with a focus on advanced imaging techniques for non-invasive assessment along with their implications for patient management. In addition, the role of and techniques to assess hepatic volume in hepatic surgery are discussed.

Comparison of correlations between lipid profile and different computed tomography fatty liver criteria in the setting of incidentally noted fatty liver on computed tomography examinations

PURPOSE

The aim of this study was to compare the correlations between computed tomography (CT) criteria for hepatic steatosis and lipid profile values when hepatic steatosis is incidentally detected.

PARTICIPANTS AND METHODS

This is an institutional Review Board-approved, HIPPA-compliant, retrospective study of abdominal CT scans in 200 randomly selected patients who had either nonenhanced CT (NECT) or contrast-enhanced CT (CECT) studies with reported fatty liver. The participants were matched for age, sex, and ethnicity with 200 patients with nonfatty liver. For NECT, four different criteria have been proposed in the literature to diagnose fatty liver: (i) liver Hounsfield Units (HU) less than 48 HU, (ii) ratio of liver to spleen HU less than 0.8, (iii) HU difference between liver and spleen less than -10, and (iv) hepatic vessel HU greater than or equal to liver HU. For CECT, the criteria was attenuation difference between liver and spleen HU, in the portal venous phase of up to -20 to -25 HU. Laboratory results (low-density lipoprotein, high-density lipoprotein, triglycerides) were documented. Matched analyses and conditional logistic regression analysis were carried out for matched variables.

RESULTS

There were statistically significant differences in triglyceride values, between the cases and controls (P=0.02), when all criteria were considered. Also, statistically significant differences were found between cases and controls on the basis of NECT criterion 2 and high-density lipoprotein (P=0.04), as well as CECT criteria and triglyceride levels (P=0.02). In addition, the data indicate that criteria for steatosis on CECT may be more broad than traditionally utilized.

CONCLUSION

Incidental reporting of fatty liver on NECT/CECT should prompt consideration of clinical follow-up and lipid profile testing in an otherwise asymptomatic patient. Additional metrics for the diagnosis of steatosis in CECT exam should also be considered.

Imaging evaluation of non-alcoholic fatty liver disease: focused on quantification

Non-alcoholic fatty liver disease (NAFLD) has been an emerging major health problem, and the most common cause of chronic liver disease in Western countries. Traditionally, liver biopsy has been gold standard method for quantification of hepatic steatosis. However, its invasive nature with potential complication as well as measurement variability are major problem. Thus, various imaging studies have been used for evaluation of hepatic steatosis. Ultrasonography provides fairly good accuracy to detect moderate-to-severe degree hepatic steatosis, but limited accuracy for mild steatosis. Operator-dependency and subjective/qualitative nature of examination are another major drawbacks of ultrasonography. Computed tomography can be considered as an unsuitable imaging modality for evaluation of NAFLD due to potential risk of radiation exposure and limited accuracy in detecting mild steatosis. Both magnetic resonance spectroscopy and magnetic resonance imaging using chemical shift technique provide highly accurate and reproducible diagnostic performance for evaluating NAFLD, and therefore, have been used in many clinical trials as a non-invasive reference of standard method.