Noninvasive liver steatosis quantification using MRI techniques combined with blood markers

Evaluation of proton density fat fraction (PDFF) obtained from a vendor-neutral MRI sequence and MRQuantif software

OBJECTIVE

To validate the proton density fat fraction (PDFF) obtained by the MRQuantif software from 2D chemical shift encoded MR (CSE-MR) data in comparison with the histological steatosis data.

METHODS

This study, pooling data from 3 prospective studies spread over time between January 2007 and July 2020, analyzed 445 patients who underwent 2D CSE-MR and liver biopsy. MR derived liver iron concentration (MR-LIC) and PDFF was calculated using the MRQuantif software. The histological standard steatosis score (SS) served as reference. In order to get a value more comparable to PDFF, histomorphometry fat fraction (HFF) were centrally determined for 281 patients. Spearman correlation and the Bland and Altman method were used for comparison.

RESULTS

Strong correlations were found between PDFF and SS (rs = 0.84, p < 0.001) or HFF (rs = 0.87, p < 0.001). Spearman's coefficients increased to 0.88 (n = 324) and 0.94 (n = 202) when selecting only the patients without liver iron overload. The Bland and Altman analysis between PDFF and HFF found a mean bias of 5.4% ± 5.7 [95% CI 4.7, 6.1]. The mean bias was 4.7% ± 3.7 [95% CI 4.2, 5.3] and 7.1% ± 8.8 [95% CI 5.2, 9.0] for the patients without and with liver iron overload, respectively.

CONCLUSION

The PDFF obtained by MRQuantif from a 2D CSE-MR sequence is highly correlated with the steatosis score and very close to the fat fraction estimated by histomorphometry. Liver iron overload reduced the performance of steatosis quantification and joint quantification is recommended. This device-independent method can be particularly useful for multicenter studies.

CLINICAL RELEVANCE STATEMENT

The quantification of liver steatosis using a vendor-neutral 2D chemical-shift MR sequence, processed by MRQuantif, is well correlated to steatosis score and histomorphometric fat fraction obtained from biopsy, whatever the magnetic field and the MR device used.

KEY POINTS

• The PDFF measured by MRQuantif from 2D CSE-MR sequence data is highly correlated to hepatic steatosis. • Steatosis quantification performance is reduced in case of significant hepatic iron overload. • This vendor-neutral method may allow consistent estimation of PDFF in multicenter studies.

Physical Activity and Low Glycemic Index Mediterranean Diet: Main and Modification Effects on NAFLD Score. Results from a Randomized Clinical Trial

Background: Non-Alcoholic Fatty Liver Disease (NAFLD) is the most common chronic liver disease worldwide, and lifestyle modification is the current standard treatment. The aim of the study was to estimate the effect of two different physical activity (PA) programs, a Low Glycemic Index Mediterranean Diet (LGIMD), and their combined effect on the NAFLD score as measured by FibroScan^®. Methods: Moderate or severe NAFLD subjects (n = 144) were randomly assigned to six intervention arms during three months. Interventions arms were a control diet, LGIMD, aerobic activity program (PA1), combined activity program (PA2), and LGIMD plus PA1 or LGIMD plus PA2. The data were compared at baseline, at 45 days, and at 90 days. Analysis of variance was performed under the intention-to-treat principle. Results: There was a statistically significant reduction in the NAFLD score after 45 days of treatment in every working arm except for Arm 1 (control diet). After 90 days, the best results were shown by the intervention arms in which LGIMD was associated with PA: LGIMD plus PA1 (−61.56 95% CI −89.61, −33.50) and LGIMD plus PA2 (−38.15 95% CI −64.53, −11.77). Conclusion: All treatments were effective to reduce NAFLD scores, but LGIMD plus PA1 was the most efficient.

A noninvasive indicator for the diagnosis of early hepatitis B virus-related liver fibrosis

BACKGROUND AND AIMS

Liver stiffness measurement (LSM) detected by FibroScan, combined with biochemical indexes, has shown potential values for assessment of liver fibrosis pathological degrees. Here we aimed to investigate a noninvasive method for hepatitis B virus-related liver fibrosis.

PATIENTS AND METHODS

In all, 307 patients who underwent liver biopsy and LSM measurement were included. Inflammation grades and fibrosis stages were evaluated according to METAVIR scoring system. Spearman's rank correlation analysis, logistic regression analysis, and receiver operating characteristic (ROC) curves analysis were performed to assess the factors' role in inflammation grades/fibrosis stages.

RESULTS

Spearman's rank correlation analysis showed that LSM, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and AST-to-platelet ratio index were positively correlated with inflammation grades and histologic fibrosis stages; platelets showed negative correlation, and AST-to-ALT ratio was not related. Logistic regression analysis indicated that LSM and APRI were risk factors for inflammation grades; LSM was the independent risk factor for fibrosis stages, P<0.0001, odds ratio>1. ROC curve analysis found LSM cutoff values and areas under the curve for the diagnosis of fibrosis scores: 6.95 and 0.804, respectively, for the diagnosis of significant fibrosis (F≥F2); 10.35 and 0.856, respectively, for severe fibrosis (F≥F3); 11.35 and 0.897, respectively, for cirrhosis (F=F4). Considering ALT as a confounding factor, ROC analysis was repeated in patients with normal and elevated ALT separately; the results indicated that when ALT was up to 40 U/l, LSM cutoff value and areas under the curve for the diagnosis of significant fibrosis (F≥F2) were 6.55 and 0.748, respectively.

CONCLUSION

This study provided a noninvasive treatment and prevention indicator for early hepatitis B virus-related liver fibrosis.

Controlled Attenuation Parameter for Assessment of Hepatic Steatosis in Indian Patients

BACKGROUND/AIMS

The gold standard method for measurement of hepatic steatosis is liver histology. Controlled Attenuation Parameter (CAP) can measure hepatic steatosis non-invasively. We aimed to assess the accuracy of CAP for detection of hepatic steatosis.

METHODS

A total of 462 patients (May 2012-January 2017)-89 non-alcoholic fatty liver disease, 182 chronic hepatitis B, 88 chronic hepatitis C and 103 patients with other etiologies who underwent simultaneous liver biopsy and CAP estimation using Transient Elastography (TE) were included. Steatosis was graded as S0: steatosis in 0-5% of hepatocytes, S1: 6-33%, S2: 34-66% and S3: 67-100%. Receiver Operating Characteristic (ROC) curves were plotted to evaluate the accuracy of CAP in detecting hepatic steatosis. Predictors of CAP were assessed by multivariate linear regression model.

RESULTS

The mean age ± SD was 33.8 ± 11.6 years; 296 (64.1%) were males. On liver histology, steatosis grades S0, S1, S2 and S3 were seen in 331 (71.6%), 74 (16.0%), 39 (8.4%) and 18 (3.9%), respectively. The median CAP (IQR) values for S0, S1, S2, and S3 steatosis were 206 (176-252) dB/m, 295 (257-331) dB/m, 320 (296-356) dB/m, and 349 (306-363) dB/m, respectively. For estimation of ≥S1, ≥S2, and ≥S3 using CAP, AUROC were 0.879, 0.893, and 0.883, respectively. In multivariate analysis, only BMI (OR 1.18; CI, 1.11-1.26, P < 0.001) and grade of hepatic steatosis (grade 1, OR, 3.94; 95% CI, 1.58-9.84, P = 0.003; grade 2, OR 42.04; 95% CI, 4.97-355.31, P = 0.001 and grade 3, OR 35.83; 95% CI 4.31-297.61, P = 0.001) independently predicted CAP.

CONCLUSIONS

CAP detects hepatic steatosis with good accuracy in Indian patients with various etiologies.

Assessment of Fat distribution and Bone quality with Trabecular Bone Score (TBS) in Healthy Chinese Men

Whether fat is beneficial or detrimental to bones is still controversial, which may be due to inequivalence of the fat mass. Our objective is to define the effect of body fat and its distribution on bone quality in healthy Chinese men. A total of 228 men, aged from 38 to 89 years, were recruited. BMD, trabecular bone score (TBS), and body fat distribution were measured by dual-energy X-ray absorptiometry. Subcutaneous and visceral fat were assessed by MRI. In the Pearson correlation analysis, lumbar spine BMD exhibited positive associations with total and all regional fat depots, regardless of the fat distribution. However, the correlation disappeared with adjusted covariables of age, BMI, HDL-C, and HbA1c%. TBS was negatively correlated with fat mass. In multiple linear regression models, android fat (and not gynoid, trunk, or limbs fat) showed significant inverse association with TBS (β = −0.611, P < 0.001). Furthermore, visceral fat was described as a pathogenic fat harmful to TBS, even after adjusting for age and BMI (β = −0.280, P = 0.017). Our findings suggested that body fat mass, especially android fat and visceral fat, may have negative effects on bone microstructure; whereas body fat mass contributes to BMD through mechanical loading.

Simultaneous liver iron and fat measures by magnetic resonance imaging in patients with hyperferritinemia

OBJECTIVE

Hyperferritinemia is frequent in chronic liver diseases of any cause, but the extent to which ferritin truly reflects iron stores is variable. In these patients, both liver iron and fat are found in variable amount and association. Liver biopsy is often required to quantify liver fat and iron, but sampling variability and invasiveness limit its use. We aimed to assess single breath-hold multiecho magnetic resonance imaging (MRI) for the simultaneous lipid and iron quantification in patients with hyperferritinemia.

MATERIAL AND METHODS

We compared MRI results for both iron and fat with their respective gold standards - liver iron concentration and computer-assisted image analysis for steatosis on biopsy. We prospectively studied 67 patients with hyperferritinemia and other 10 consecutive patients were used for validation. We estimated two linear calibration equations for the prediction of iron and fat based on MRI. The agreement between MRI and biopsy was evaluated.

RESULTS

MRI showed good performances in both the training and validation samples. MRI information was almost completely in line with that obtained from liver biopsy.

CONCLUSION

Single breath-hold multiecho MRI is an accurate method to obtain a valuable measure of both liver iron and steatosis in patients with hyperferritinemia.

Republished: Non-alcoholic fatty liver disease: non-invasive investigation and risk stratification

Non-alcoholic fatty liver disease (NAFLD) encompasses a histological spectrum of liver disease, from simple steatosis through to cirrhosis. As the worldwide rates of obesity have increased, NAFLD has become the commonest cause of liver disease in many developed countries, affecting up to a third of the population. The majority of patients have simple steatosis that carries a relatively benign prognosis. However, a significant minority have non-alcoholic steatohepatitis, and have increased liver related and cardiovascular mortality. Identifying those at risk of progressive disease is crucial. Liver biopsy remains the gold standard investigation for assessing stage of disease but its invasive nature makes it impractical for widespread use as a prognostic tool. Non-invasive tools for diagnosis and disease staging are required, reserving liver biopsy for those patients where it offers clinically relevant additional information. This review discusses the non-invasive modalities available for assessing steatosis, steatohepatitis and fibrosis. We propose a pragmatic approach for the assessment of patients with NAFLD to identify those at high risk of progressive disease who require referral to specialist services.

Controlled attenuation parameter for noninvasive assessment of hepatic steatosis using Fibroscan®: validation in chronic hepatitis B

BACKGROUND AND AIM

The controlled attenuation parameter (CAP) using transient elastography (TE) was validated in chronic hepatitis C to evaluate hepatic steatosis; however, limited data are available on chronic hepatitis B (CHB). Therefore, we assessed the accuracy and the efficacy of CAP for the detection of steatosis in CHB.

METHODS

Consecutive CHB patients underwent liver biopsy and liver stiffness measurements (LSM) with simultaneous CAP determination using the M probe of the TE. The area under the receiver operating characteristics curve (AUROC) was used to evaluate the performance of CAP in diagnosing steatosis compared with biopsy.

RESULTS

A total of 340 patients were included: 60 % were male, the median age was 37 years; the body mass index (BMI) was ≥ 28 kg/m(2) for 14 % of the subjects; and the distribution of the steatosis grade was S0 58.2 %, S1 34.2 %, S2 5.0 % and S3 2.6 %. The median (range) of CAP was 218 (100-400) dB/m, and CAP correlated with the BMI (ρ = 3.622) and steatosis grade (ρ = 29.203) according to a multivariate analysis (both P < 0.001). CAP could detect the different grades of steatosis: ≥ S1 with AUROC of 0.81 at a cutoff of 224 dB/m, ≥ S2 with AUROC of 0.90 at a cutoff of 236 dB/m and ≥ S3 with AUROC of 0.97 at a cutoff of 285 dB/m. Furthermore, the LSM and fibrosis and activity grades on biopsy did not influence the CAP performance.

CONCLUSIONS

CAP presented excellent diagnostic performance for severe steatosis with high sensitivity and specificity in Chinese patients with CHB.

EFFECT OF HELICOBACTER PYLORI ERADICATION ON HEPATIC STEATOSIS, NAFLD FIBROSIS SCORE AND HSENSI IN PATIENTS WITH NONALCOHOLIC STEATOHEPATITIS: a MR imaging-based pilot open-label study

Context Limited clinical data suggest Helicobacter pylori (Hp) infection may contribute to nonalcoholic fatty liver disease (NAFLD) pathogenesis. Objectives The effect of Hp eradication on hepatic steatosis (magnetic resonance imaging), nonalcoholic fatty liver disease fibrosis score and HSENSI (Homocysteine, serum glutamic oxaloacetic transaminase, Erythrocyte sedimentation rate, nonalcoholic steatohepatitis Index) in nonalcoholic steatohepatitis patients. Methods Thirteen adult patients with biopsy-proven nonalcoholic steatohepatitis, asymptomatic for gastrointestinal disease, underwent 13C urea breath test; Hp positive patients received eradication therapy until repeat test become negative. Hepatic fat fraction, standard biochemical tests and calculation of nonalcoholic fatty liver disease fibrosis score and HSENSI were performed at baseline and month 12. Results Hepatic fat fraction was similar for between and within group comparisons. Nonalcoholic fatty liver disease fibrosis score showed a non-significant trend towards decrease in Hp(+) [-0.34 (-1.39-0.29) at baseline and -0.24 (-0.99-0.71) at month 12; P = 0.116], whereas increase in Hp(-) group [-0.38 (-1.72-0.11) and -0.56 (-1.43-0.46), respectively; P = 0.249]. HSENSI was significantly decreased only in Hp(+) group [1.0 (1.0-2.0) at baseline and 1.0 (0-1.0) at month 12; P = 0.048]. Conclusions Hp eradication had no long-term effect on hepatic steatosis, but showed a trend towards improvement in nonalcoholic fatty liver disease fibrosis score and HSENSI. These results warrant larger studies with paired biopsies.

Novel equation to determine the hepatic triglyceride concentration in humans by MRI: diagnosis and monitoring of NAFLD in obese patients before and after bariatric surgery

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is caused by abnormal accumulation of lipids within liver cells. Its prevalence is increasing in developed countries in association with obesity, and it represents a risk factor for non-alcoholic steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma. Since NAFLD is usually asymptomatic at diagnosis, new non-invasive approaches are needed to determine the hepatic lipid content in terms of diagnosis, treatment and control of disease progression. Here, we investigated the potential of magnetic resonance imaging (MRI) to quantitate and monitor the hepatic triglyceride concentration in humans.

METHODS

A prospective study of diagnostic accuracy was conducted among 129 consecutive adult patients (97 obesity and 32 non-obese) to compare multi-echo MRI fat fraction, grade of steatosis estimated by histopathology, and biochemical measurement of hepatic triglyceride concentration (that is, Folch value).

RESULTS

MRI fat fraction positively correlates with the grade of steatosis estimated on a 0 to 3 scale by histopathology. However, this correlation value was stronger when MRI fat fraction was linked to the Folch value, resulting in a novel equation to predict the hepatic triglyceride concentration (mg of triglycerides/g of liver tissue = 5.082 + (432.104 * multi-echo MRI fat fraction)). Validation of this formula in 31 additional patients (24 obese and 7 controls) resulted in robust correlation between the measured and estimated Folch values. Multivariate analysis showed that none of the variables investigated improves the Folch prediction capacity of the equation. Obese patients show increased steatosis compared to controls using MRI fat fraction and Folch value. Bariatric surgery improved MRI fat fraction values and the Folch value estimated in obese patients one year after surgery.

CONCLUSIONS

Multi-echo MRI is an accurate approach to determine the hepatic lipid concentration by using our novel equation, representing an economic non-invasive method to diagnose and monitor steatosis in humans.

Role of sex steroids, intrahepatic fat and liver enzymes in the association between SHBG and metabolic features

BACKGROUND

SHBG and liver enzymes levels are both associated with the risk of type 2 diabetes. However, the relationship between SHBG with liver enzymes and intrahepatic fat content remain poorly understood.

OBJECTIVE

To investigate whether SHBG is correlated with glucose and lipids levels and whether this association depends on fatty liver content, liver enzymes or sex hormone concentrations.

DESIGN AND PATIENTS

We studied 233 dysmetabolic men with measures of plasma SHBG, total testosterone, 17β-oestradiol, glucose, adiponectin, liver enzymes and hepatokines. Intrahepatic liver fat and visceral fat contents were measured by magnetic resonance imaging in 108 of these individuals.

RESULTS

After adjustment for age, SHBG concentration was inversely correlated with fasting glucose (βstandardized  = -0·21, P = 0·0007), HbA1c (βstandardized  = -0·27, P < 0·0001), triglycerides (βstandardized  = -0·19, P = 0·003) and positively correlated with HDL-Cholesterol (βstandardized  = 0·14, P = 0·03). These correlations persisted after adjustment for either total testosterone or 17β-oestradiol levels. SHBG was not related to either fetuin A or FGF 21 concentrations. The inverse association of SHBG with HbA1c and glycaemia was not altered after adjusting for liver markers but was no longer significant after adjustment for hepatic fat content.

CONCLUSION

The significant association between SHBG and fasting glycaemia, HbA1c and lipid levels in dysmetabolic men was not related to either sex hormones or markers of liver function, but was dependent on intrahepatic fat. This suggests that intrahepatic fat, but not alterations in liver function markers, may be involved in the association between SHBG and glucose and lipid metabolism.

Non-alcoholic fatty liver disease: non-invasive investigation and risk stratification

Non-alcoholic fatty liver disease (NAFLD) encompasses a histological spectrum of liver disease, from simple steatosis through to cirrhosis. As the worldwide rates of obesity have increased, NAFLD has become the commonest cause of liver disease in many developed countries, affecting up to a third of the population. The majority of patients have simple steatosis that carries a relatively benign prognosis. However, a significant minority have non-alcoholic steatohepatitis, and have increased liver related and cardiovascular mortality. Identifying those at risk of progressive disease is crucial. Liver biopsy remains the gold standard investigation for assessing stage of disease but its invasive nature makes it impractical for widespread use as a prognostic tool. Non-invasive tools for diagnosis and disease staging are required, reserving liver biopsy for those patients where it offers clinically relevant additional information. This review discusses the non-invasive modalities available for assessing steatosis, steatohepatitis and fibrosis. We propose a pragmatic approach for the assessment of patients with NAFLD to identify those at high risk of progressive disease who require referral to specialist services.

Controlled attenuation parameter for non-invasive assessment of hepatic steatosis: does etiology affect performance?

BACKGROUND

Hepatic steatosis is an important parameter to assess in chronic liver disease patients. The controlled attenuation parameter (CAP) assesses liver steatosis using transient elastography.

AIM

To determine the accuracy of CAP for evaluation of hepatic steatosis in chronic hepatitis B virus (CHBV)-infected, chronic hepatitis C virus (CHCV)-infected, and non-alcoholic fatty liver disease (NAFLD) patients and to determine the influence of etiology on the diagnostic accuracy of CAP.

METHODS

One hundred forty-six CHBV patients, 108 CHCV-infected patients and 63 patients with NAFLD, who underwent both liver biopsy and successful CAP measurements within the study period, were assessed. Area under the receiver operating characteristics was used to evaluate performance of CAP for diagnosing steatosis compared with biopsy.

RESULTS

Multivariate analysis found that CAP correlated with body mass index (odds ratio, 95% confidence interval = 4.09 [1.2-6.8] for CHBV; 4.7 [1.1-8.4] for CHCV, and 16.2 [9.1-24.5] for NAFLD patients respectively) and hepatic steatosis score on biopsy (odds ratio, 95% confidence interval = 30.7 [19.2-42.2] for CHBV; 24.2 [11.5-37.3] for CHCV, and 21.8 [10.1-45.0] for NAFLD patients respectively). Area under the receiver operating characteristics for CAP was 0.683 (0.601-0.757) for steatosis (S) ≥ 6%, 0.793 (0.718-0.856) for S > 33%, and 0.841 (0.771-0.896) for S > 66% respectively for CHBV-infected patients. There was no difference in accuracy of CAP for assessing liver fat among CHBV, CHCV, and NAFLD patients.

CONCLUSIONS

CAP is a novel, non-invasive tool that can detect and quantify steatosis accurately among CHBV, CHCV, and NAFLD patients, the accuracy being similar for all the three groups of patients.

Diagnostic performance of a rapid magnetic resonance imaging method of measuring hepatic steatosis

OBJECTIVES

Hepatic steatosis is associated with an increased risk of developing serious liver disease and other clinical sequelae of the metabolic syndrome. However, visual estimates of steatosis from histological sections of biopsy samples are subjective and reliant on an invasive procedure with associated risks. The aim of this study was to test the ability of a rapid, routinely available, magnetic resonance imaging (MRI) method to diagnose clinically relevant grades of hepatic steatosis in a cohort of patients with diverse liver diseases.

MATERIALS AND METHODS

Fifty-nine patients with a range of liver diseases underwent liver biopsy and MRI. Hepatic steatosis was quantified firstly using an opposed-phase, in-phase gradient echo, single breath-hold MRI methodology and secondly, using liver biopsy with visual estimation by a histopathologist and by computer-assisted morphometric image analysis. The area under the receiver operating characteristic (ROC) curve was used to assess the diagnostic performance of the MRI method against the biopsy observations.

RESULTS

The MRI approach had high sensitivity and specificity at all hepatic steatosis thresholds. Areas under ROC curves were 0.962, 0.993, and 0.972 at thresholds of 5%, 33%, and 66% liver fat, respectively. MRI measurements were strongly associated with visual (r(2) = 0.83) and computer-assisted morphometric (r(2) = 0.84) estimates of hepatic steatosis from histological specimens.

CONCLUSIONS

This MRI approach, using a conventional, rapid, gradient echo method, has high sensitivity and specificity for diagnosing liver fat at all grades of steatosis in a cohort with a range of liver diseases.

MRI measurement of liver fat content predicts the metabolic syndrome

BACKGROUND AND AIMS

The prevalence of non-alcoholic fatty liver disease among cardiometabolic patients is not completely known because liver biopsy cannot be routinely performed. However, as magnetic resonance imaging (MRI) allows accurate and safe measurement of the hepatic fat fraction (HFF), the aim of this study was to quantify liver fat content in a dysmetabolic adult population.

METHODS

A total of 156 adults were included in this cross-sectional study. Liver and visceral fat were assessed by MRI in these subjects, who presented with zero to five metabolic components of the metabolic syndrome (MetS). Arterial stiffness was recorded by ultrasonography, and the maximum Youden index was used to set the optimal HFF cutoff value predictive of the presence of the MetS.

RESULTS

Overall, 72% of participants displayed three or more MetS components. HFF ranged from 0.3% to 52% (mean 13.4%). Age- and gender-adjusted HFF was positively correlated with BMI (r=0.44), blood pressure (r=0.19), triglyceridaemia (r=0.22) and glycaemia (r=0.31). MRI-measured visceral adipose tissue did not influence the relationship of steatosis with glycaemia, HOMA-IR and carotid stiffness, but there was a dose-response relationship between the number of MetS components and mean HFF. The optimal HFF for predicting the MetS was found to be 5.2% according to the maximum Youden index point.

CONCLUSION

This study highlighted the impact of liver steatosis on cardiometabolic abnormalities with an optimal cutoff value of 5.2% for defining increased metabolic risk.

Sonographic hepatorenal ratio: a noninvasive method to diagnose nonalcoholic steatosis

PURPOSE

To evaluate the accuracy of the sonographic hepatorenal ratio (HRR) in the diagnosis and grading of nonalcoholic steatosis, using biopsy as the reference.

METHODS

Ultrasound (US) and liver biopsy were performed in 42 patients with nonalcoholic fatty liver disease. Forty healthy volunteers without steatosis at US and without risk factors for nonalcoholic fatty liver disease were also studied. The HRR was obtained by dividing the mean brightness level of region-of-interest pixels in hepatic parenchyma by that in renal parenchyma. Needle biopsy samples (hematoxylin-eosin stained) were classified as mild (5-33% fatty infiltration), moderate (>33-66%), or severe (>66%) steatosis. Spearman coefficient was used to evaluate the correlation between HRR and steatosis grade, analysis of variance for differences between subgroups, and receiver operating characteristic curve analysis for sensitivity and specificity.

RESULTS

Significant correlation was found between HRR and histologic steatosis (r = 0.80, p < 0.01). The HRR cutoff for predicting steatosis was ≥1.24 (sensitivity, 92.7%; specificity, 92.5%). The mean ± SD HRRs in controls and steatosis subgroups were control 1.09 ± 0.13, mild 1.46 ± 0.24, moderate 1.52 ± 0.27, severe 2.04 ± 0.3 and were significantly different from each other except between mild and moderate steatosis subgroups.

CONCLUSIONS

The HRR is a noninvasive, objective, and simple method that could be used to diagnose and grade hepatic steatosis.

Fatty liver in acute pancreatitis: characteristics in magnetic resonance imaging

OBJECTIVE

The objective of this research was to study the characteristics of fatty liver (FL) in acute pancreatitis (AP) in 2-dimensional in-phase (IP)/out-of-phase (OP) magnetic resonance imaging (MRI).

METHODS

Fifty patients with AP (23 men, 27 women; mean age, 44 [SD, 12] years [range, 16-73 years]) were included in this retrospective study. Patients' informed consent was waived. All of them performed abdominal MRI within 72 hours of symptom onset and MRI follow-up. The severity of the AP was graded according to the magnetic resonance severity index (MRSI). The MRSI cutoff was 7.0 points between the mild and the severe AP. Fatty liver in MRI was determined by the hepatic signal intensity difference between OP and IP images. Correlations between the severity of FL and MRSI or serum triglyceride levels were analyzed.

RESULTS

Of the 50 patients with AP, FL was found in 66% of patients' MRIs. A close correlation can be seen between the difference of liver signal intensities on IP/OP images and the MRSI (r = 0.83, P < 0.001). Close correlations were found between FL appearance on MRI and serum triglyceride levels in both mild (r = 0.93, P < 0.001) and severe AP (r = 0.95, P < 0.001). During follow-up MRI, the appearance of FL decreased following the decrease in MRSI scores and serum triglyceride levels in both mild and severe AP.

CONCLUSIONS

Fatty liver in AP is frequently observed in MRI. The appearance of FL in MRI may decrease after subsidence of AP.

Two- versus three-dimensional dual gradient-echo MRI of the liver: a technical comparison

OBJECTIVE

To compare 2D spoiled dual gradient-echo (SPGR-DE) and 3D SPGR-DE with fat and water separation for the assessment of focal and diffuse fatty infiltration of the liver.

METHODS

A total of 227 consecutive patients (141 men; 56 ± 14 years) underwent clinically indicated liver MRI at 1.5 T including multiple-breath-hold 2D SPGR-DE and single-breath-hold 3D SPGR-DE with automatic reconstruction of fat-only images. Two readers assessed the image quality and number of fat-containing liver lesions on 2D and 3D in- and opposed-phase (IP/OP) images. Liver fat content (LFC) was quantified in 138 patients without chronic liver disease from 2D, 3D IP/OP, and 3D fat-only images.

RESULTS

Mean durations of 3D and 2D SPGR-DE acquisitions were 23.7 ± 2.9 and 97.2 ± 9.1 s respectively. The quality of all 2D and 3D images was rated diagnostically. Three-dimensional SPGR-DE revealed significantly more breathing artefacts resulting in lower image quality (P < 0.001); 2D and 3D IP/OP showed a similar detection rate of fat-containing lesions (P = 0.334) and similar LFC estimations (mean: +0.4 %; P = 0.048). LFC estimations based on 3D fat-only images showed significantly higher values (mean: 2.7 % + 3.5 %) than those from 2D and 3D IP/OP images (P < 0.001).

CONCLUSION

Three dimensional SPGR-DE performs as well as 2D SPGR-DE for the assessment of focal and diffuse fatty infiltration of liver parenchyma. The 3D SPGR-DE sequence used was quicker but more susceptible to breathing artefacts. Significantly higher LFC values are derived from 3D fat-only images than from 2D or 3D IP/OP images.

Role of quantification of hepatic steatosis and future remnant volume in predicting hepatic dysfunction and complications after liver resection for colorectal metastases: a pilot study

OBJECTIVES

Accurate prediction of safe remnant liver volume to minimize complications following liver resection remains challenging. The aim of this study was to assess whether quantification of steatosis improved the predictive value of preoperative volumetric analysis.

METHODS

Thirty patients undergoing planned right or extended right hemi-hepatectomy for colorectal metastases were recruited prospectively. Magnetic resonance imaging was used to assess the level of hepatic steatosis and future remnant liver volume. These data were correlated with data on postoperative hepatic insufficiency, complications and hospital stay. Correlations of remnant percentage, remnant mass to patient mass and remnant mass to body surface area with and without steatosis measurements were assessed.

RESULTS

In 10 of the 30 patients the planned liver resection was altered. Moderate-severe postoperative hepatic dysfunction was seen in 17 patients. Complications arose in 14 patients. The median level of steatosis was 3.8% (range: 1.2-17.6%), but was higher in patients (n= 10) who received preoperative chemotherapy (P= 0.124), in whom the median level was 4.8% (range: 1.5-17.6%). The strongest correlation was that of remnant liver mass to patient mass (r= 0.77, P < 0.001). However, the addition of steatosis quantification did not improve this correlation (r= 0.76, P < 0.001).

CONCLUSIONS

This is the first study to combine volumetric with steatosis quantifications. No significant benefit was seen in this small pilot. However, these techniques may be useful in operative planning, particularly in patients receiving preoperative chemotherapy.

Steatosis degree, measured by morphometry, is linked to other liver lesions and metabolic syndrome components in patients with NAFLD

BACKGROUND AND AIM

We carried out morphometric measurements of steatosis to evaluate relationships between steatosis degree and other liver lesions or metabolic syndrome components in nonalcoholic fatty liver disease (NAFLD).

PATIENTS AND METHODS

We developed an algorithm to measure steatosis area. Two hundred and fourteen patients with NAFLD were included in derivation (10) and validation (204) groups. Controls consisted of patients who were steatosis-free (12), patients with chronic hepatitis C (188), and patients with alcoholic chronic liver disease (94).

RESULTS

Accuracy of steatosis area was considered as good or very good in at least 72% of cases by three pathologists. Steatosis areas were as follows: NAFLD = 10.3 ± 9.7%, virus = 2.4 ± 3.1%, alcohol = 7.8 ± 8.2% (P<0.0001). Steatosis area was closely related to steatosis grades in NAFLD (P<0.0001 for linear trend). Steatosis area increased from the fibrosis stage F0 to the fibrosis state F2, then decreased in the stages F3 and F4 (cirrhosis) (P<0.0001 for quadratic trend). Fibrosis was present in an average steatosis area of approximately 4% (defining significant steatosis) and in nonalcoholic steatohepatitis by approximately 8% (defining severe steatosis). Steatosis and fibrosis area increased symmetrically until approximately 10%, then steatosis area decreased to null as average fibrosis area reached 32%. Average fasting glycemia (approximately 92 mg/dl) or triglycerides and BMI plateaued before a steatosis area of approximately 4%, then increased thereafter. Significant steatosis was present in 61.3% of NAFLD versus 20.2% of viral hepatitis (P<0.0001) and in 58.7% of alcoholic liver diseases (P=0.674).

CONCLUSIONS

The average threshold of steatosis area is 4% for the development of fibrosis or metabolic syndrome components and 8% for nonalcoholic steatohepatitis. Steatosis area may contribute to defining the normal range and clinical course of metabolic components.