Detection of hepatic steatosis on contrast-enhanced CT images: diagnostic accuracy of identification of areas of presumed focal fatty sparing. AJR Am J Roentgenol. 2012;199:44-47. [PMID: 22733892 DOI: 10.2214/ajr.11.7838]

Nonalcoholic fatty liver disease following laparoscopic duodenum-preserving pancreatic total head resection vs laparoscopic pancreaticoduodenectomy: A retrospective cohort study

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is characterized by the accumulation of fat in the liver in individuals who do not consume alcohol. Several risk factors influencing the onset of NAFLD after laparoscopic pancreaticoduodenectomy (LPD) have been identified. This study investigated the risk factors associated with the development of fatty liver after laparoscopic duodenum-preserving pancreatic total head resection (LDPPHRt) and LPD.

AIM

To compare the effects of LDPPHRt and LPD on the development of postoperative NAFLD.

METHODS

This retrospective cohort study included 59 patients who were histologically diagnosed with benign or low-grade malignant pancreatic tumors and who underwent laparoscopic pancreatic surgery (LDPPHRt or LPD) between May 2020 and April 2023. Patient data on perioperative and postoperative variables were analyzed and compared. Multivariate logistic regression was used to identify pre-, peri-, and postoperative risk factors for NAFLD, with statistical significance set at P < 0.05.

RESULTS

Of the 59 patients included in the study, 17 (28.8%) developed NAFLD within 6-12 months post-surgery. The incidence of NAFLD was significantly higher in the LPD group compared to the LDPPHRt group (40.0% vs 12.5%, P = 0.022). Multivariable analysis identified the LDPPHRt surgical approach (compared to LPD) as an independent protective factor against the development of postoperative NAFLD, with an odds ratio of 0.208 (95% confidence interval: 0.046-0.931; P = 0.040).

CONCLUSION

Our findings indicate that LDPPHRt is more effective than LPD in reducing the incidence of postoperative NAFLD, which may inform surgical decision-making and optimize patient outcomes after laparoscopic pancreatic surgery.

Novel Quantitative Liver Steatosis Assessment Method With Ultrasound Harmonic Imaging

OBJECTIVES

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most prevalent liver disorder in Western countries, with approximately 20%-30% of the MASLD patients progressing to severe stages. There is an urgent need for noninvasive, cost-effective, widely accessible, and precise biomarkers to evaluate liver steatosis. This study aims to assess and compare the diagnostic performance of a novel reference frequency method-based ultrasound attenuation coefficient estimation (ACE) in both fundamental (RFM-ACE-FI) and harmonic (RFM-ACE-HI) imaging for detecting and grading liver steatosis.

METHODS

An Institutional Review Board-approved prospective study was carried out between December 2018 and October 2022. A total number of 130 subjects were enrolled in the study. The correlation between RFM-ACE-HI values and magnetic resonance imaging proton density fat fraction (MRI-PDFF), as well as between RFM-ACE-FI values and MRI-PDFF were calculated. The diagnostic performance of RFM-ACE-FI and RFM-ACE-HI was evaluated using receiver operating characteristic (ROC) curve analysis, as compared to MRI-PDFF. The reproducibility of RFM-ACE-HI was assessed by interobserver agreement between two sonographers.

RESULTS

A strong correlation was observed between RFM-ACE-HI and MRI-PDFF, with R = 0.88 (95% confidence interval [CI]: 0.83-0.92; P < .001), while the correlation between RFM-ACE-FI and MRI-PDFF was R = 0.65 (95% CI: 0.50-0.76; P < .001). The area under the ROC (AUROC) curve for RFM-ACE-HI in staging liver steatosis grades of S ≥ 1 and S ≥ 2 was 0.97 (95% CI: 0.91-0.99; P < .001) and 0.98 (95% CI: 0.93-1.00; P < .001), respectively, and 0.76 (95% CI: 0.65-0.85) and 0.80 (95% CI: 0.70-0.88) for RFM-ACE-FI, respectively. Great reproducibility was achieved for RFM-ACE-HI, with an interobserver agreement of R = 0.97 (95% CI: 0.94-0.99; P < .001).

CONCLUSIONS

The novel RFM-ACE-HI method offered high liver steatosis diagnostic accuracy and reproducibility, which has important clinical implications for early disease intervention and treatment evaluation.

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

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

The Hyperdense Right Hemidiaphragm Sign: A Novel Radiological Indicator of Diffuse Fatty Liver Infiltration on Non-Enhanced CT

Objectives The primary objective of this study is to describe and evaluate the diagnostic performance of the hyperdense right hemidiaphragm sign (HRHS) as a novel radiological indicator for diffuse fatty infiltration of the liver on non-enhanced CT (NECT) scans. This includes assessing its sensitivity, specificity, positive predictive value, and negative predictive value, and comparing these metrics with other established NECT signs. Methods This cross-sectional multicenter retrospective study included all patients over 12 years of age who underwent both abdominal MRI and NECT scans of the abdomen within a period not exceeding six months at two tertiary hospitals (The Royal Hospital and Armed Forces Hospital, Muscat, Sultanate of Oman) between January 2010 and December 2022. Two readers reviewed the NECT scan images for the following signs: HRHS, liver density of less than 10 HU compared to the spleen, absolute liver density of <40 HU, and hyperattenuated intrahepatic vessels. The drop in signal on the out-phase sequence compared to the in-phase sequence on MRI was used as the gold standard reference for diagnosing diffuse fatty infiltration of the liver. Data were analyzed using IBM SPSS Statistics for Windows, Version 26.0 (Released 2019; IBM Corp., Armonk, NY, USA) and MedCalc software (MedCalc Software Ltd., Oostende, Belgium), with sensitivity, specificity, and positive and negative predictive values calculated for each NECT sign. Results A total of 340 patients were included in this study, with a mean age of 54 years. Among these patients, 45 were diagnosed with diffuse fatty infiltration of the liver by MRI. Thirty-six patients were identified as positive for fatty liver infiltration on unenhanced CT based on the criterion of the HRHS, with a sensitivity of 91%, specificity of 99%, positive predictive value of 94%, and negative predictive value of 99%. In contrast, 45 patients were positive using the criterion of liver density less than 10 HU compared to the spleen, yielding a sensitivity of 83%, a specificity of 98%, a positive predictive value of 88%, and a negative predictive value of 97%. Using the criterion of absolute liver density <40 HU, 30 patients were positive, with a sensitivity of 72%, specificity of 98%, positive predictive value of 90%, and negative predictive value of 96%. Lastly, 20 patients were positive using the criterion of hyperattenuated intrahepatic vessels, with a sensitivity of 51%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 93%. Conclusions The proposed qualitative evaluation using the HRHS for diffuse fatty infiltration of the liver on NECT scans demonstrates the highest sensitivity compared to other previously described NECT signs.

Diagnostic Accuracy of CT for the Detection of Hepatic Steatosis: A Systematic Review and Meta-Analysis

Background CT plays an important role in the opportunistic identification of hepatic steatosis. CT performance for steatosis detection has been inconsistent across various studies, and no clear guidelines on optimum thresholds have been established. Purpose To conduct a systematic review and meta-analysis to assess CT diagnostic accuracy in hepatic steatosis detection and to determine reliable cutoffs for the commonly mentioned measures in the literature. Materials and Methods A systematic search of the PubMed, Embase, and Scopus databases (English-language studies published from September 1977 to January 2024) was performed. Studies evaluating the diagnostic accuracy of noncontrast CT (NCCT), contrast-enhanced (CECT), and dual-energy CT (DECT) for hepatic steatosis detection were included. Reference standards included biopsy, MRI proton density fat fraction (PDFF), or NCCT. In several CECT and DECT studies, NCCT was used as the reference standard, necessitating subgroup analysis. Statistical analysis included a random-effects meta-analysis, assessment of heterogeneity with use of the I2 statistic, and meta-regression to explore potential sources of heterogeneity. When available, mean liver attenuation, liver-spleen attenuation difference, liver to spleen attenuation ratio, and the DECT-derived fat fraction for hepatic steatosis diagnosis were assessed. Results Forty-two studies (14 186 participants) were included. NCCT had a sensitivity and specificity of 72% and 88%, respectively, for steatosis (>5% fat at biopsy) detection and 82% and 94% for at least moderate steatosis (over 20%-33% fat at biopsy) detection. CECT had a sensitivity and specificity of 66% and 90% for steatosis detection and 68% and 93% for at least moderate steatosis detection. DECT had a sensitivity and specificity of 85% and 88% for steatosis detection. In the subgroup analysis, the sensitivity and specificity for detecting steatosis were 80% and 99% for CECT and 84% and 93% for DECT. There was heterogeneity among studies focusing on CECT and DECT. Liver attenuation less than 40-45 HU, liver-spleen attenuation difference less than -5 to 0 HU, and liver to spleen attenuation ratio less than 0.9-1 achieved high specificity for detection of at least moderate steatosis. Conclusion NCCT showed high performance for detection of at least moderate steatosis. © RSNA, 2024 Supplemental material is available for this article.

MASLD: What We Have Learned and Where We Need to Go-A Call to Action

Since its introduction in 1980, fatty liver disease (now termed metabolic dysfunction-associated steatotic liver disease [MASLD]) has grown in prevalence significantly, paralleling the rise of obesity worldwide. While MASLD has been the subject of extensive research leading to significant progress in the understanding of its pathophysiology and progression factors, several gaps in knowledge remain. In this pictorial review, the authors present the latest insights into MASLD, covering its recent nomenclature change, spectrum of disease, epidemiology, morbidity, and mortality. The authors also discuss current qualitative and quantitative imaging methods for assessing and monitoring MASLD. Last, they propose six unsolved challenges in MASLD assessment, which they term the proliferation, reproducibility, reporting, needle-in-the-haystack, availability, and knowledge problems. These challenges offer opportunities for the radiology community to proactively contribute to their resolution. The authors conclude with a call to action for the entire radiology community to claim a seat at the table, collaborate with other societies, and commit to advancing the development, validation, dissemination, and accessibility of the imaging technologies required to combat the looming health care crisis of MASLD.

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.

Cross-sectional imaging after pancreatic surgery: The dialogue between the radiologist and the surgeon

Pancreatic surgery is nowadays considered one of the most complex surgical approaches and not unscathed from complications. After the surgical procedure, cross-sectional imaging is considered the non-invasive reference standard to detect early and late compilations, and consequently to address patients to the best management possible. Contras-enhanced computed tomography (CECT) should be considered the most important and useful imaging technique to evaluate the surgical site. Thanks to its speed, contrast, and spatial resolution, it can help reach the final diagnosis with high accuracy. On the other hand, magnetic resonance imaging (MRI) should be considered as a second-line imaging approach, especially for the evaluation of biliary findings and late complications. In both cases, the radiologist should be aware of protocols and what to look at, to create a robust dialogue with the surgeon and outline a fitted treatment for each patient.

Comparative analysis of perioperative and long-term outcomes of patients with hepatocellular carcinoma: Nonalcoholic fatty liver disease versus viral hepatitis

BACKGROUND

Despite the accumulating evidence regarding the oncological differences between nonalcoholic fatty liver disease (NAFLD)-related hepatocellular carcinoma (HCC) and viral infection-related HCC, the short- and long-term outcomes of surgical resection of NAFLD-related HCC remain unclear. While some reports indicate improved postoperative survival in NAFLD-related HCC, other studies suggest higher postoperative complications in these patients.

METHODS

Patients with NAFLD and those with hepatitis viral infection who underwent hepatectomy for HCC at our department were retrospectively analyzed. The clinical, surgical, pathological, and survival outcomes were compared between the two groups.

RESULTS

Among the 1047 consecutive patients who underwent hepatectomy for HCC, 57 had NAFLD-related HCC (NAFLD group), and 727 had virus-related HCC (VH group). The body mass index and serum glycated hemoglobin levels were significantly higher in the NAFLD group than in the VH group. There were no significant differences in operative time and bleeding amount. Moreover, the morbidity and the length of postoperative hospital stays were similar across both groups. The pathological results showed that the tumor size was significantly larger in the NAFLD group than in the VH group. No significant differences between the groups in overall or recurrence-free survival were found. In a subgroup analysis with matched tumor diameters, patients in the NAFLD group had a better prognosis after hepatectomy than those in the VH group.

CONCLUSION

Surgical outcomes after hepatectomy were comparable between the groups. Subgroup analysis reveals early detection and surgical intervention in NAFLD-HCC may improve prognosis.

Metabolic syndrome: imaging features and clinical outcomes

Metabolic syndrome, which affects around a quarter of adults worldwide, is a group of metabolic abnormalities characterized mainly by insulin resistance and central adiposity. It is strongly correlated with cardiovascular and all-cause mortality. Early identification of the changes induced by metabolic syndrome in target organs and timely intervention (eg, weight reduction) can decrease morbidity and mortality. Imaging can monitor the main components of metabolic syndrome and identify early the development and progression of its sequelae in various organs. In this review, we discuss the imaging features across different modalities that can be used to evaluate changes due to metabolic syndrome, including fatty deposition in different organs, arterial stiffening, liver fibrosis, and cardiac dysfunction. Radiologists can play a vital role in recognizing and following these target organ injuries, which in turn can motivate lifestyle modification and therapeutic intervention.

ACR Appropriateness Criteria® Abnormal Liver Function Tests

Liver function tests are commonly obtained in symptomatic and asymptomatic patients. Various overlapping lab patterns can be seen due to derangement of hepatocytes and bile ducts function. Imaging tests are pursued to identify underlying etiology and guide management based on the lab results. Liver function tests may reveal mild, moderate, or severe hepatocellular predominance and can be seen in alcoholic and nonalcoholic liver disease, acute hepatitis, and acute liver injury due to other causes. Cholestatic pattern with elevated alkaline phosphatase with or without elevated γ-glutamyl transpeptidase can be seen with various causes of obstructive biliopathy. Acute or subacute cholestasis with conjugated or unconjugated hyperbilirubinemia can be seen due to prehepatic, intrahepatic, or posthepatic causes. We discuss the initial and complementary imaging modalities to be used in clinical scenarios presenting with abnormal liver function tests. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Artificial Intelligence Applications in Hepatology

Over the past 2 decades, the field of hepatology has witnessed major developments in diagnostic tools, prognostic models, and treatment options making it one of the most complex medical subspecialties. Through artificial intelligence (AI) and machine learning, computers are now able to learn from complex and diverse clinical datasets to solve real-world medical problems with performance that surpasses that of physicians in certain areas. AI algorithms are currently being implemented in liver imaging, interpretation of liver histopathology, noninvasive tests, prediction models, and more. In this review, we provide a summary of the state of AI in hepatology and discuss current challenges for large-scale implementation including some ethical aspects. We emphasize to the readers that most AI-based algorithms that are discussed in this review are still considered in early development and their utility and impact on patient outcomes still need to be assessed in future large-scale and inclusive studies. Our vision is that the use of AI in hepatology will enhance physician performance, decrease the burden and time spent on documentation, and reestablish the personalized patient-physician relationship that is of utmost importance for obtaining good outcomes.

Improved Ultrasound Attenuation Estimation with Non-uniform Structure Detection and Removal

Accurate detection of liver steatosis is important for liver disease management. Ultrasound attenuation coefficient estimation (ACE) has great potential in quantifying liver fat content. The ACE methods commonly assume uniform tissue characteristics. However, in vivo tissues typically contain non-uniform structures, which may bias the attenuation estimation and lead to large standard deviations. Here we propose a series of non-uniform structure detection and removal (NSDR) methods to reduce the impact from non-uniform structures during ACE analysis. The effectiveness of NSDR was validated through phantom and in vivo studies. In a pilot clinical study, ACE with NSDR provided more robust in vivo performance as compared with ACE without NSDR, indicating its potential for in vivo applications.

The impact of pylorus preservation on the development of nonalcoholic fatty liver disease after pancreaticoduodenectomy: A historical cohort study

BACKGROUND/PURPOSE

The pathophysiology and associated factors of nonalcoholic fatty liver disease (NAFLD) after pancreaticoduodenectomy (PD) remain elusive. We aimed to investigate these factors, including the operation type, for NAFLD development after PD.

METHODS

This historical cohort study included 786 consecutive patients treated with either classic Whipple operation or pylorus-preserving pancreaticoduodenectomy (PPPD) in Korea between 2012 and 2018. De novo NAFLD was determined based on hepatic attenuation in nonenhanced computed tomography during follow-up.

RESULTS

Of the 786 patients, 216 (27.5%) had a newly developed NAFLD at 2 years after PD. The incidences of newly developed NAFLD at 0.5, 1, 1.5, and 2 years were 13 (1.7%), 41 (5.2%), 48 (6.1%), and 114 (14.5%), respectively. The Whipple group showed a significantly higher incidence of NAFLD than the PPPD group (40.3% vs 24.5%, P < .001). Seventeen patients (2.2%) had severe fatty liver with abnormal liver enzymes. Multivariable analysis revealed that Whipple operation (vs PPPD; adjusted odds ratio [AOR]: 1.92, P < .001) and high preoperative body mass index (vs normal; AOR: 1.71, P = .001) were independently associated with a higher risk of NAFLD.

CONCLUSION

The incidence of NAFLD was 27.5% at 2 years after PD. Undergoing Whipple operation and high preoperative body mass index were significantly associated with de novo NAFLD development.

Individualized Contrast Media Application Based on Body Weight and Contrast Enhancement in Computed Tomography of Livers without Steatosis

This study analyzes the homogeneity in liver attenuation of a body-weight-based protocol compared to a semi-fixed protocol. Patients undergoing abdominal multiphase computed tomography received 0.500 g of iodine (gI) per kilogram of body weight. Liver attenuation and enhancement were determined using regions of interest on scans in the pre-contrast and portal venous phases. The outcomes were analyzed for interpatient uniformity in weight groups. The subjective image quality was scored using a four-point Likert scale (excellent, good, moderate, and nondiagnostic). A total of 80 patients were included (56.3% male, 64 years, 78.0 kg) and were compared to 80 propensity-score-matched patients (62.5% male, 63 years, 81.7 kg). The liver attenuation values for different weight groups of the TBW-based protocol were not significantly different (p = 0.331): 109.1 ± 13.8 HU (≤70 kg), 104.6 ± 9.70 HU (70−90 kg), and 105.1 ± 11.6 HU (≥90 kg). For the semi-fixed protocol, there was a significant difference between the weight groups (p < 0.001): 121.1 ± 12.1 HU (≤70 kg), 108.9 ± 11.0 HU (70−90 kg), and 105.0 ± 9.8 HU (≥90 kg). For the TBW-based protocol, the enhancement was not significantly different between the weight groups (p = 0.064): 46.2 ± 15.1 HU (≤70 kg), 59.3 ± 6.8 HU (70−90 kg), and 52.1 ± 11.7 HU (≥90 kg). Additionally, for the semi-fixed protocol, the enhancement was not significantly different between the weight groups (p = 0.069): 59.4 ± 11.0 HU (≤70 kg), 53.0 ± 10.3 HU (70−90 kg), and 52.4 ± 7.5 HU (≥90 kg). The mean administered amount of iodine per kilogram was less for the TBW-based protocol compared to the semi-fixed protocol: 0.499 ± 0.012 and 0.528 ± 0.079, respectively (p = 0.002). Of the TBW-based protocol, 17.5% of the scans scored excellent enhancement quality, 76.3% good, and 6.3% moderate. Of the semi-fixed protocol, 70.0% scored excellent quality, 21.3% scored good, and 8.8% scored moderate. In conclusion, the TBW-based protocol increased the interpatient uniformity of liver attenuation but not the enhancement in the portal venous phase compared to the semi-fixed protocol, using an overall lower amount of contrast media and maintaining good subjective image quality.

Is Fat Deposition of Renal Sinus a Concomitant Finding to Fatty Liver Disease? The First Study Regarding the Relationship Between Kidney and Liver Fat Content with Non-Contrast Computed Tomography

INTRODUCTION

It has been established that abnormal fat deposits are associated with fat deposition in other abdominal regions and linked to obesity, diabetes mellitus, hypertension, vascular and metabolic diseases. This study aimed to determine whether there was a relationship between fat deposition of the renal (i.e., kidney) sinus (FRS) and fatty liver disease (FLD) in a sample of adults. The authors hypothesized that FRS could be a diagnostic finding associated with Hepatosteatosis (HS) in a sample of younger patients. This study was the first apparent investigation of this possible phenomenon.

METHODS

A convenience sample of 92 adult patients of which 19 (20.7%) were females and 73 (79.3%) were males, and with a mean age of 30.19 (SD = 6.00) were included. The authors calculated Hounsfield Units (HU) (i.e., relative quantitative measurement of radio density) of patients' livers and spleens on non-contrast computed tomography (CT). Liver and spleen differences < 10 HU were considered steatosis (FLD). The authors stratified sample patients into two analytic subgroups according to the presence of FLD or not and compared them based on their FRS widths.

RESULTS

In the FLD subgroup (N = 48), the difference of HU values between liver and spleen was -5.19 (SD = 11.32), with a range of -38 - 8 HU, while, in the non-steatosis subgroup (N = 44), the mean difference was 16.36 (SD = 3.90), range of 11 - 26 HU. The average diameter of FRS width was 12.5 mm in those patients with steatosis (FLD subgroup) although 9.3 mm in non-FLD patients. (p = 0.02).

CONCLUSIONS

Based on these results, FRS may be able to be used by radiologists as an ancillary method in the detection of hepatic steatosis in younger adults. The effectiveness of premedical processes (e.g., exercise and diet modification) can also be increased by non-radiologists after detection of lower-grade HS.

Liver Enhancement on Computed Tomography Is Suboptimal in Patients with Liver Steatosis

This study's aim was twofold. Firstly, to assess liver enhancement quantitatively and qualitatively in steatotic livers compared to non-steatotic livers on portal venous computed tomography (CT). Secondly, to determine the injection volume of contrast medium in patients with severe hepatic steatosis to improve the image quality of the portal venous phase. We retrospectively included patients with non-steatotic (n = 70), the control group, and steatotic livers (n = 35) who underwent multiphase computed tomography between March 2016 and September 2020. Liver enhancement was determined by the difference in attenuation in Hounsfield units (HU) between the pre-contrast and the portal venous phase, using region of interests during in three different segments. Liver steatosis was determined by a mean attenuation of ≤40 HU on unenhanced CT. Adequate enhancement was objectively defined as ≥50 ΔHU and subjectively using a three-point Likert scale. Enhancement of non-steatotic and steatotic livers were compared and associations between enhancement and patient- and scan characteristics were analysed. Enhancement was significantly higher among the control group (mean 51.9 ± standard deviation 11.5 HU) compared to the steatosis group (40.6 ± 8.4 HU p for difference < 0.001). Qualitative analysis indicated less adequate enhancement in the steatosis group: 65.7% of the control group was rated as good vs. 8.6% of the steatosis group. We observed a significant correlation between enhancement, and presence/absence of steatosis and grams of iodine per total body weight (TBW) (p < 0.001; adjusted R2 = 0.303). Deduced from this correlation, theoretical contrast dosing in grams of Iodine (g I) can be calculated: g I = 0.502 × TBW for non-steatotic livers and g I = 0.658 × TBW for steatotic livers. Objective and subjective enhancement during CT portal phase were significantly lower in steatotic livers compared to non-steatotic livers, which may have consequences for detectability and contrast dosing.

The associations between coronary artery disease, and non-alcoholic fatty liver disease by computed tomography

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is increasing in recognition as a hepatic condition that is unrelated to significant alcoholic consumption, but has rather, been suggested to constitute cardiovascular risk (irrespective of traditional risk factors and high-risk plaque features). Both coronary artery disease and NAFLD share the same pathophysiology and metabolic profile. NAFLD can theoretically be a source/initiator for coronary artery disease (CAD). We aimed to study the association between NAFLD, CAD, the presence of high-risk plaque features, and the severity of stenosis.

RESULTS

We recruited 800 patients with suspected obstructive CAD and planned for coronary computed tomography angiography (CCTA), Exclusion criteria: heavy alcohol consumption; contraindications to contrast media; unevaluated coronary-artery segments; other known liver disease; and use of oral corticosteroids and/or amiodarone. Non-enhanced Computed Tomography abdomen was performed before the CCTA to detect NAFLD. To study the association between NAFLD and the presence of CAD, patients were classified as to either have, or not have CAD. The CAD group were then further studied for the presence of high-risk plaque features: napkin ring sign, Positive remodelling, Low Hounsfield unit (HU), and Spotty calcium; and their association with NAFLD. Thirty-two per cent of patients had NAFLD and 45% had CAD. A significant association between NAFLD and CAD was found (OR 4.21, 95% CI (confidence interval) (2.83-6.25), p = 0.000). In CAD patients, significant associations were present between NAFLD and high-risk plaque features: Napkin ring sign, Positive remodelling, Low HU, and Spotty calcium (OR 7.88, 95% CI (4.39-14.12), p < 0.001, OR 5.84, 95% (3.85-8.85), p < 0.001, OR 7.25, 95% CI (3.31-15.90), p < 0.001 and OR 6.66, 95% CI (3.75-11.82), p < 0.001), respectively. NAFLD was present in 39.30%, 50.00%, 20.00%, 54.50% and 100.00% of patients with CAD; and 1-24%; 25-49%; 50-69%; 7 = 0-99%, LMD (Left Main Disease) > 50% stenosis or 3V disease, and Total occlusion, respectively, p < 0.001.

CONCLUSIONS

NAFLD is strongly associated with CAD, high-risk plaque features and higher grade of stenosis.

Evaluation of Adjuvant Chemotherapy-Associated Steatosis (CAS) in Colorectal Cancer

Chemotherapy-associated steatosis is poorly understood in the context of colorectal cancer. In this study, Stage II–III colorectal cancer patients were retrospectively selected to evaluate the frequency of chemotherapy-associated steatosis and to determine whether patients on statins throughout adjuvant chemotherapy develop chemotherapy-associated steatosis at a lower frequency. Baseline and incident steatosis for up to one year from chemotherapy start date was assessed based on radiology. Of 269 patients, 76 (28.3%) had steatosis at baseline. Of the remaining 193 cases, patients receiving adjuvant chemotherapy (n = 135) had 1.57 (95% confidence interval [CI], 0.89 to 2.79) times the adjusted risk of developing steatosis compared to patients not receiving chemotherapy (n = 58). Among patients who underwent chemotherapy, those using statins for pre-existing hyperlipidemia (n = 37) had 0.71 (95% CI, 0.10 to 2.75) times the risk of developing steatosis compared to patients who were not prevalent users of statins (n = 98). Chemotherapeutic treatment of Stage II–III colorectal cancer appears to be consistent with a moderately increased risk of steatosis, although larger studies are necessary to assess the significance of this observation. Prospective trials should be considered to further explore the potential for protective use of statins in this curative patient population.

Hepatic steatosis: a risk factor for increased COVID-19 prevalence and severity-a computed tomography study

BACKGROUND

Around 25% of the world population was affected by the metabolic-related fatty liver disorder. Hepatic steatosis is frequently observed in conjunction with hypertension, obesity comorbidities, and diabetes. We evaluate the hepatic steatosis frequency found in chest CT exams of COVID-19-positive cases compared to non-infected controls and evaluate the related increased prevalence and severity of COVID.

RESULTS

Our research includes 355 subjects, 158 with positive PCR for COVID-19 (case group) and 197 with negative PCR and negative CT chest (control group). The mean age in the positive group was 50.6 ± 16 years, and in the control, it was 41.3 ± 16 years (p < 0.001). Our study consists of 321 men (90.5%) and 34 women (9.5%). The number of males in both cases and control groups was greater. In the case group, 93% men vs. 6.9% women, while in controls, 88.3% men vs.11.6% women, p < 0.001. CT revealed normal results in 55.5% of individuals (i.e., CORADs 1) and abnormal findings in 45.5% of participants (i.e., CORADs 2-5). In abnormal scan, CO-RADs 2 was 13.92%, while CO-RADs 3-4 were 20.89% of cases. CO-RADs 5 comprised 65.19% of all cases. Approximately 42.6% of cases had severe disease (CT score ≥ 20), all of them were CO-RADs 5. The PCR-positive class had a greater prevalence of hepatic steatosis than controls (28.5% vs.12.2%, p < 0.001). CO-RADs 2 represented 11.1%, CO-RADs 3-4 represented 15.6%, and CO-RADs 5 represented 73.3% in the hepatic steatosis cases. The mean hepatic attenuation value in the case group was 46.79 ± 12.68 and in the control group 53.34 ± 10.28 (p < 0.001). When comparing patients with a higher severity score (CT score ≥ 20) to those with non-severe pneumonia, it was discovered that hepatic steatosis is more prevalent (73.2% vs. 26.8%).

CONCLUSIONS

Steatosis was shown to be substantially more prevalent in COVID-19-positive individuals. There is a relation among metabolic syndrome, steatosis of the liver, and obesity, as well as the COVID-19 severity.

Under-reporting of Hepatic Steatosis in Children: A Missed Opportunity for Early Detection

OBJECTIVE

To determine the prevalence of underreporting of hepatic steatosis found incidentally on computed tomography (CT).

STUDY DESIGN

Retrospective cross-sectional study including patients <18 years of age who had undergone unenhanced abdominal CT for evaluation of nephrolithiasis. Hepatic and splenic attenuation were measured independently by 2 reviewers. Hepatic steatosis was defined using various previously established criteria (4 original criteria designed to detect moderate/severe steatosis and 3 secondary criteria designed to identify mild steatosis). Radiology reports and clinical notes were reviewed for documentation of steatosis. Serum alanine aminotransferase levels were collected. Kappa statistics were used to assess agreement between reviewers.

RESULTS

A total of 584 patients were included. Agreement between reviewers' measurements for categorical classification of presence of steatosis was excellent (kappa statistic agreement >87%). The prevalence of hepatic steatosis ranged from 3% to 35%, depending on the criterion. Using absolute liver attenuation <48 Hounsfield units (most likely reflective of the truth, given alanine aminotransferase distribution and body mass index data), the prevalence was 7% (n = 42). Steatosis was reported for only 12 of 42 (28%) of these patients and was documented in clinical notes in only 3 of those cases.

CONCLUSIONS

Hepatic steatosis is underreported as an incidental finding of CT for nephrolithiasis. Given the prevalence and silent nature of nonalcoholic fatty liver disease, a high level of suspicion is needed, so as not to miss the opportunity to identify steatosis in childhood.

Frequency of hepatic steatosis and its association with the pneumonia severity score on chest computed tomography in adult COVID-19 patients

BACKGROUND

Recent studies of the coronavirus disease 2019 (COVID-19) demonstrated that obesity is significantly associated with increased disease severity, clinical outcome, and mortality. The association between hepatic steatosis, which frequently accompanies obesity, and the pneumonia severity score (PSS) evaluated on computed tomography (CT), and the prevalence of steatosis in patients with COVID-19 remains to be elucidated.

AIM

To assess the frequency of hepatic steatosis in the chest CT of COVID-19 patients and its association with the PSS.

METHODS

The chest CT images of 485 patients who were admitted to the emergency department with suspected COVID-19 were retrospectively evaluated. The patients were divided into two groups as COVID-19-positive [CT- and reverse transcriptase-polymerase chain reaction (RT-PCR)-positive] and controls (CT- and RT-PCR-negative). The CT images of both groups were evaluated for PSS as the ratio of the volume of involved lung parenchyma to the total lung volume. Hepatic steatosis was defined as a liver attenuation value of ≤ 40 Hounsfield units (HU).

RESULTS

Of the 485 patients, 56.5% (n = 274) were defined as the COVID-19-positive group and 43.5% (n = 211) as the control group. The average age of the COVID-19-positive group was significantly higher than that of the control group (50.9 ± 10.9 years vs 40.4 ± 12.3 years, P < 0.001). The frequency of hepatic steatosis in the positive group was significantly higher compared with the control group (40.9% vs 19.4%, P < 0.001). The average hepatic attenuation values were significantly lower in the positive group compared with the control group (45.7 ± 11.4 HU vs 53.9 ± 15.9 HU, P < 0.001). Logistic regression analysis showed that after adjusting for age, hypertension, diabetes mellitus, overweight, and obesity there was almost a 2.2 times greater odds of hepatic steatosis in the COVID-19-positive group than in the controls (odds ratio 2.187; 95% confidence interval: 1.336-3.580, P < 0.001).

CONCLUSION

The prevalence of hepatic steatosis was significantly higher in COVID-19 patients compared with controls after adjustment for age and comorbidities. This finding can be easily assessed on chest CT images.

Association of Cardiovascular Risk Factors and Metabolic Syndrome with non-alcoholic and alcoholic fatty liver disease: a retrospective analysis

BACKGROUND

Although many studies on non-alcoholic fatty liver disease (NAFLD) are underway worldwide, and several existing studies have investigated the association between NAFLD and cardiovascular risk factors, studies comparing NAFLD and alcoholic fatty liver disease (AFLD) are scarce. This study aimed to evaluate differences between the incidence of cardiovascular risk factors and metabolic syndrome in NAFLD and AFLD.

METHODS

A retrospective analysis of 913 patients who underwent abdominal computed tomography (CT) was performed to compare the incidence of cardiovascular risk factors and metabolic syndrome between NAFLD and AFLD. Subjects were divided into three groups based on criteria: healthy (n = 572), NAFLD (n = 295), and AFLD (n = 46). The healthy group had no liver disease. NAFLD was defined as fatty liver diagnosed on CT and drinking less than 140 g/week for men or 70 g/week for women. AFLD was defined as fatty liver diagnosed on CT and drinking more than 140 g/week for men or 70 g/week for women. We compared the incidence of cardiovascular risk factors and metabolic syndrome between the three groups. The relationship between each group and the metabolic syndrome risk was analyzed through multivariate logistic regression analysis.

RESULTS

No significant differences in several cardiovascular risk factors were observed between the NAFLD and AFLD groups. Upon analyzing the metabolic syndrome status in each group after making appropriate adjustments, the odds ratios (ORs) in the NAFLD (OR = 2.397, P = 0.002) and AFLD groups (OR = 4.445, P = 0.001) were found to be significantly higher than that in the healthy group; the incidence rate of metabolic syndrome was similar in the NAFLD and AFLD groups.

CONCLUSIONS

Both the NAFLD and AFLD groups had more cardiovascular risk factors and higher metabolic syndrome risk than the healthy group. Thus, the prevention of fatty liver disease, regardless of the specific type, should involve the identification of cardiovascular and metabolic syndrome risk factors. If abdominal CT reveals a fatty liver, whether NAFLD or AFLD, the risk of cardiovascular disease and metabolic syndrome should be assessed.

Association of the Serum Uric Acid-to-Creatinine Ratio with Nonalcoholic Fatty Liver Disease Diagnosed by Computed Tomography

Background: Although previous studies have suggested that the serum uric acid-to-creatinine ratio (sUA/Cr) is associated with metabolic syndrome, there is limited evidence of a relationship between sUA/Cr and nonalcoholic fatty liver disease (NAFLD). In this study, we investigated the association between sUA/Cr and NAFLD in healthy adults. Methods: A cross-sectional analysis was performed in 778 subjects who participated in a health examination. The participants were divided according to presence of NAFLD, which was determined by abdominal computed tomography (CT). Logistic regression analysis was performed to investigate the variables associated with NAFLD, and an adjusted odds ratio (OR) of sUA/Cr for NAFLD was estimated. Results: sUA/Cr in participants with NAFLD was significantly higher than in those without NAFLD. Multivariate analysis demonstrated significant association between sUA/Cr and NAFLD, and the adjusted OR of sUA/Cr increase of 1 for NAFLD was 1.182. (95% CI: 1.066-1.311). Conclusions: Elevated sUA/Cr was significantly associated with CT-diagnosed NAFLD in healthy adults. sUA/Cr may be a reliable marker for predicting NAFLD. (The Clinical Trial Registration number: 2020-06-002-002).

Diagnostic significance of the CT rim sign in cases of gangrenous cholecystitis

PURPOSE

To evaluate the association between the CT rim sign and gangrenous cholecystitis (GC) and increased surgical difficulty.

METHOD

Patients who had a contrast enhanced CT of the abdomen and pelvis, followed by non-elective cholecystectomy were analyzed. The scans were reviewed for the CT rim sign by radiologists blinded to the pathologic and clinical outcomes. Demographic and clinical characteristics were compared between patients with and without GC using t-tests or Wilcoxon ranked sum test for continuous variables, and Fishers' exact test for categorical variables, when appropriate. A logistic regression model was fitted with multiple risk factors. Odds ratios as well as 95% confidence intervals were then calculated for the risk factors. A secondary analysis predicting increased surgical difficulty, defined as an operative time of greater than 2 h or increased conversion rate to open surgery, was also examined.

RESULTS

A total of 100 patients were included; 20 of which had GC. On imaging, patients with GC were more likely to have a CT rim sign (65% vs 32.5%, OR = 3.80, 95% CI: 1.24-12.7, p = 0.011). The presence of the CT rim sign did not reach a statistically significant association with an operative time >2 h or conversion to open case (56.52% vs 33.77%, OR = 2.55, p = 0.056).

CONCLUSION

The CT rim sign can be utilized to raise the possibility of GC, however the presence of the CT rim sign does not demonstrate an association with increased surgical difficulty.

Ultrasound Attenuation Estimation in Harmonic Imaging for Robust Fatty Liver Detection

Accurate detection of liver steatosis is important for liver disease management. Ultrasound attenuation coefficient estimation (ACE) has great potential in quantifying liver fat content. The commonly used ACE methods (e.g., spectral shift methods, reference phantom methods) assume linear tissue response to ultrasound and were developed in fundamental imaging. However, fundamental imaging may be vulnerable to reverberation clutters introduced by the body wall. The clutters superimposed on liver echoes may bias the attenuation estimation. Here we propose a new ACE technique, the reference frequency method (RFM), in harmonic imaging to mitigate the reverberation bias. The accuracy of harmonic RFM was validated through a phantom study. In a pilot patient study, harmonic RFM performed more robustly in vivo compared with fundamental RFM, illustrating the potential of ACE in harmonic imaging.

Classification of hepatocellular carcinoma and intrahepatic cholangiocarcinoma based on multi-phase CT scans

Liver and bile duct cancers are leading causes of worldwide cancer death. The most common ones are hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). Influencing factors and prognosis of HCC and ICC are different. Precise classification of these two liver cancers is essential for treatment and prevention plans. The aim of this study is to develop a machine-based method that differentiates between the two types of liver cancers from multi-phase abdominal computerized tomography (CT) scans. The proposed method consists of two major steps. In the first step, the liver is segmented from the original images using a convolutional neural network model, together with task-specific pre-processing and post-processing techniques. In the second step, by looking at the intensity histograms of the segmented images, we extract features from regions that are discriminating between HCC and ICC, and use them as an input for classification using support vector machine model. By testing on a dataset of labeled multi-phase CT scans provided by Maharaj Nakorn Chiang Mai Hospital, Thailand, we have obtained 88% in classification accuracy. Our proposed method has a great potential in helping radiologists diagnosing liver cancer.

Pre-transplant hepatic steatosis (fatty liver) is associated with chronic graft-vs-host disease but not mortality

Allogeneic-HCT (allo-HCT), while potentially curative, can result in significant complications including graft versus host disease (GVHD). Prior studies suggest that metabolic syndrome may be one risk factor for GVHD. We hypothesized that hepatic steatosis on pre-HCT computed tomography (CT) scans may be a marker for development of GVHD and poor outcomes in allo-HCT. In this retrospective study, we reviewed the pre-HCT CT scans and transplant outcome data of patients who underwent allo-HCT at Duke University Medical Center from 2009 to 2017. The presence of steatosis was confirmed using CT attenuation measurements. We then assessed the association between pre-HCT hepatic steatosis and HCT-related outcomes including GVHD. 80 patients who had pre-HCT CT scans were included in the study. Pre-transplant hepatic steatosis was associated with the development of chronic GVHD (OR 4.2, p = 0.02), but was not associated with acute GVHD (OR 1.3, p = 0.7), non-relapse mortality (p = 0.81) or overall survival (p = 0.74). Based on this single center retrospective study, pre-transplant hepatic steatosis is associated with development of chronic GVHD. Further, prospective study with other imaging modalities including non-contrasted CT scans is needed to determine if this association is reproducible.

Liver Steatosis Secondary to PRRT With 177Lu-DOTATATE: An Unknown Adverse Effect

PRRT (peptide receptor radionuclide therapy) with Lu-DOTATATE for neuroendocrine tumor has some well-known adverse effects, concerning specially the bone marrow and kidneys. Hepatotoxicity has been rarely reported, and there are no data regarding hepatic steatosis secondary to PRRT. We reviewed upper abdomen CT and MRI and applied radiologic criteria for the diagnosis of hepatic steatosis on 62 patients treated between the years of 2010 and 2017. Two patients already showed radiologic signs of steatosis in the middle of the treatment and through follow-up all patients showed improvement of the steatosis.

Advances in Imaging of Diffuse Parenchymal Liver Disease

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

Higher frequency of hepatic steatosis at CT among COVID-19-positive patients

Purpose

Recent studies have demonstrated that obesity is significantly associated with increased disease severity, hospitalizations and mortality in COVID-19, with a potential role in the pathogenesis and prevalence in the new pandemic. The association with hepatic steatosis, however, a condition closely related to obesity within the spectrum of systemic metabolic dysfunctions, remains to be elucidated. We aimed to evaluate the frequency of hepatic steatosis as incidentally detected in chest CT examinations of COVID-19 positive patients in comparison to non-infected controls.

Methods

A retrospective study was performed with 316 patients (204 RT-PCR positive; 112 RT-PCR negative and chest CT negative). Steatosis was measured with placement of a single ROI in the right lobe of the liver (segments VI-VII) and defined as a liver attenuation value ≤ 40 HU.

Results

The frequency of hepatic steatosis was higher in the RT-PCR positive group in comparison to controls (31.9% vs. 7.1%, p < 0.001). Logistic linear regression analysis showed a 4.7 times odds of steatosis in the COVID-19 positive group as compared to controls after adjusting for age and sex (OR 4.698; 95% IC 2.12–10.41, p < 0.001).

Conclusion

A significantly higher prevalence of steatosis was found among COVID-19 positive individuals. These findings are in accordance with other recent studies linking obesity and COVID-19 infection, as there is an intricate relationship between liver steatosis, metabolic syndrome and obesity. Further studies are required to confirm if such association remains after accounting for multiple variables, as well as possible relationships with disease severity and worst clinical outcomes.

Recommendations for the Management of Incidental Hepatobiliary Findings in Adults: Endorsement and Adaptation of the 2017 and 2013 ACR Incidental Findings Committee White Papers by the Canadian Association of Radiologists Incidental Findings Working Group

The Canadian Association of Radiologists Incidental Findings Working Group consists of both academic subspecialty and general radiologists and is tasked with adapting and expanding upon the American College of Radiology incidental findings white papers to more closely apply to Canadian practice patterns, particularly more comprehensively dealing with the role of ultrasound and pursuing more cost-effective approaches to the workup of incidental findings without compromising patient care. Presented here are the 2020 Canadian guidelines for the management of hepatobiliary incidental findings. Topics covered include initial assessment of hepatic steatosis and cirrhosis, the workup of incidental liver masses identified on ultrasound and computed tomography (with algorithms presented), incidental gallbladder findings (wall thickening, calcification, and polyps), and management of incidental biliary dilatation.

Nonfetal Imaging During Pregnancy: Acute Abdomen/Pelvis

Abdominal pain is a common occurrence in pregnant women and may have a variety of causes, including those that are specific to pregnancy (eg, round ligament pain in the first trimester) and the wide range of causes of abdominal pain that affect men and women who are not pregnant (eg, appendicitis, acute cholecystitis). Noncontrast magnetic resonance (MR) imaging is increasingly performed to evaluate pregnant women with abdominal pain, either as the first-line test or as a second test following ultrasonography. The imaging appearance of causes of abdominal pain in pregnant women are reviewed with an emphasis on noncontrast MR imaging.

Radiological Advances in Pancreatic Islet Transplantation

Type 1 diabetes mellitus (T1DM) is characterized by hyperglycemia, owing to the loss of pancreatic β cells in response to an autoimmune reaction leading to a state of absolute insulin deficiency. T1DM treatment is shifting from exogenous insulin replacement therapy toward pancreatic β-cell replacement, to restore physiologically responsive insulin secretion to variations in blood glucose levels. β-cell replacement strategies include human whole pancreas transplantation, islet transplantation with cell encapsulation and bioengineered pancreas. Interventional radiology and imaging modalities including positron emission tomography, single-photon emission computed tomography, magnetic resonance imaging, ultrasonography, and molecular imaging are imperative to enable successful β-cell replacement. Herein, the role of radiological modalities in the treatment of T1DM and its prospective use for noninvasive post-transplantation graft monitoring is discussed.

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.

Focal hypersteatosis: a pseudolesion in patients with liver steatosis

PURPOSE

We aimed to describe ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) findings of focal hypersteatosis (FHS).

METHODS

We retrospectively reviewed our database for patients with hypersteatosis. Over a 5-year period (February 2005 to September 2010) a total of 17 321 patients underwent abdominal CT scan and 28 patients were determined to have FHS. All patients had US, CT, and MRI studies. Size, area, and density measurements were performed on CT images. Fat signal percentage (FSP) was measured on T1-weighted in- and out-of-phase gradient-echo images. FHS was defined based on MRI findings, as an area of greater signal drop on out-of phase images compared with the rest of the fatty liver.

RESULTS

The period prevelance of focal hypersteatosis was measured as 0.16% over the 5-year period. Cancer was the most common diagnosis (22 of 28 patients, 78.5%), with the breast (32.1%) and colorectal (25%) cancers predominating. FHS was seen in segment 4 (n=26, 92.8%), segment 8 (n=1, 3.6%), and segment 3 (n=1, 3.6%). Shape was nodular in 21 patients (75%), while triangular or amorphous in the remaining 7 patients (25%). FHS was hyperechoic and isoechoic in 5 (17.9%) and 23 (82.1%) patients, respectively. FHS was hypodense on CT of all patients relative to fatty liver. On MRI, the FHS was hyperintense on T1-weighted in-phase images in 17 patients (60.7%). Median liver parenchymal FSP was 21.5% (range, 10%-41.4%) and median FSP of hypersteatotic area was 32.5% (range, 19%-45%).

CONCLUSION

Focal hypersteatosis is a pseudolesion that can be observed in patients with liver steatosis. It appears hypodense on CT and mostly isoechoic on US relative to fatty liver. It may mimic metastasis in cancer patients with steatosis, due to nodular shape and atypical location. MRI should be used for correct diagnosis in patients with equivocal findings on CT to avoid biopsy.

Prediabetes and Type 2 Diabetes are Independent Risk Factors for Computed Tomography-Estimated Nonalcoholic Fatty Pancreas Disease

OBJECTIVES

Nonalcoholic fatty pancreas disease (NAFPD) is characterized by excessive fat deposition in the pancreas in the absence of alcohol consumption. In this study, we aimed to detect a possible relationship between adipose tissue accumulation, prediabetes and diabetes.

METHODS

This cross-sectional and retrospective study included 110 patients. Three groups were classified as controls, patients with prediabetes and patients with type 2 diabetes. The abdominal computed tomography (CT) attenuation measurement results of the pancreas were evaluated independently by two experienced radiologists. CT measurements and biochemical parameters were compared between study groups. The relationship between continuous variables was assessed by using one-way ANOVA. To determine the changes in the dependent variable for the effects on study groups, the independent variable was adjusted using ANCOVA. A p-value less than 0.05 was considered statistically significant.

RESULTS

The presence of prediabetes and type 2 diabetes was correlated with a decrease in the mean Hounsfield Unit (HU) value of the pancreas (p=0.002). Age was determined to be an independent risk factor and was correlated with NAFPD (p=0.0001). When compared to the controls (p=0.041), 71% of patients with prediabetes and 67% of patients with type 2 diabetes were observed to have an increased incidence of NAFPD. Decreased serum amylase was found to be correlated with the mean HU value of the pancreas (p=0.043).

CONCLUSION

NAFPD was independently correlated with both prediabetes and type 2 diabetes adjusted for age (p=0.0001) in this study. Additionally, age was determined to be an independent risk factor and was correlated with NAFPD.

Hepatic steatosis is highly prevalent across the paediatric age spectrum, including in pre-school age children

BACKGROUND

The prevalence of non-alcoholic fatty liver disease (NAFLD) in children is 8% in the general population, and 34% in the context of obesity. There is a paucity of data on the prevalence of hepatic steatosis in healthy children in Ontario.

AIMS

To determine the prevalence of hepatic steatosis using abdominal computed tomography (CT) scans in a cohort of previously healthy children across the paediatric age spectrum in Ontario, Canada, and to determine any association between measures of abdominal adiposity and hepatic steatosis.

METHODS

Retrospective review of the SickKids Trauma Database from 2004-2015. Previously healthy children ages 1-17 years having undergone an abdominal CT scan as a part of routine trauma assessment were included, and those with an intra-abdominal injury excluded. Steatosis was defined as a difference between liver and spleen attenuation ≤-25HU. The percentage of the total area occupied by abdominal subcutaneous adipose and visceral adipose tissue was measured. Anthropometrics and baseline demographics were collected.

RESULTS

A total of 503 (51% male) children with mean (±SD) age 9.5 ± 4.5 years and weight z-score of 0.37 ± 1.05 were studied. Seventy-seven (15%, 95% CI [12%-18%]) had hepatic steatosis; no differences found between sexes or across age quartiles. The abdominal subcutaneous adipose tissue area was greater in those with hepatic steatosis compared to those without (32% [22-42] vs 24% [17-36], P = 0.003). The visceral adipose tissue area was significantly greater in older children ≥9.8 years with hepatic steatosis (7.7% [5.1-10] vs 6.6% (4.9-8.5), P = 0.04).

CONCLUSION

Hepatic steatosis was highly prevalent in previously healthy children in Ontario, including children of pre-school age. We found an association between hepatic steatosis and abdominal subcutaneous adipose tissue, and in older children with visceral adipose tissue.

Fat Quantification in the Abdomen

Fatty liver disease is characterized histologically by hepatic steatosis, the abnormal accumulation of lipid in hepatocytes. It is classified into alcoholic fatty liver disease and nonalcoholic fatty liver disease, and is an increasingly important cause of chronic liver disease and cirrhosis. Assessing the severity of hepatic steatosis in these conditions is important for diagnostic and prognostic purposes, as hepatic steatosis is potentially reversible if diagnosed early. The criterion standard for assessing hepatic steatosis is liver biopsy, which is limited by sampling error, its invasive nature, and associated morbidity. As such, noninvasive imaging-based methods of assessing hepatic steatosis are needed. Ultrasound and computed tomography are able to suggest the presence of hepatic steatosis based on imaging features, but are unable to accurately quantify hepatic fat content. Since Dixon's seminal work in 1984, magnetic resonance imaging has been used to compute the signal fat fraction from chemical shift-encoded imaging, commonly implemented as out-of-phase and in-phase imaging. However, signal fat fraction is confounded by several factors that limit its accuracy and reproducibility. Recently, advanced chemical shift-encoded magnetic resonance imaging methods have been developed that address these confounders and are able to measure the proton density fat fraction, a standardized, accurate, and reproducible biomarker of fat content. The use of these methods in the liver, as well as in other abdominal organs such as the pancreas, adrenal glands, and adipose tissue will be discussed in this review.

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.

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.

Can ultrasound elastography identify mass-like focal fatty change (FFC) from liver mass?

Focal fatty change (FFC) may mimic liver mass on conventional B-mode ultrasound. Clinical differentiation of mass-like FFC and liver mass is important due to different clinical interventions. Contrast-enhanced imaging (CEI) or biopsy is reliable for this differentiation, but is expensive and invasive. This study aimed to explore utilities of ultrasound elastography for this differentiation.This study enrolled 79 patients with focal liver lesions (FLLs), of which 26 were mass-like FFC confirmed by at least 2 CEI modalities. The other 53 were liver masses, confirmed by pathology (n = 28) or at least 2 CEI modalities (n = 25). Lesion stiffness value (SV), absolute stiffness difference (ASD), and stiffness ratio (SR) of lesion to background were obtained using point shear-wave elastography (pSWE) and compared between FFC group and liver mass group. The performance of SV, ASD, and SR for identifying FFC from liver mass was evaluated.SV was 5.6 ± 2.4 versus 16 ± 12 kPa, ASD was 2.0 ± 1.9 versus 11 ± 12 kPa, and SR was 1.4 ± 0.6 versus 3.0 ± 1.9 for FFC and liver mass group, respectively (P < .0001). The area under the receiver operating characteristic curve of SV, ASD, and SR for discriminating mass-like FFC and liver mass was 0.840, 0.842, and 0.791, respectively (P < .05). Particularly, with cut-off ASD < 1.0 kPa, positive predictive value was 100%, specificity was 100%, and accuracy was 82% for diagnosing FFC.pSWE may be a potential useful modality for identifying mass-like FFC from liver mass, which might help reduce the necessity for further CEI or biopsy for diagnosing mass-like FFC.