Evaluation of hepatic metabolic activity in non-alcoholic fatty livers on 18FDG PET/CT

PET Imaging of Bromodomain and Extra-Terminal Domain Inhibitors for the Noninvasive Assessment of Metabolic Changes in the Liver and Brain of Early-Stage Alcoholic Liver Disease

Alcoholic liver disease (ALD) has a significant impact on human health and is one of the leading causes of liver disease mortality. The early and exact diagnosis of ALD is very important since the early stage of disease progression can be reversible. Although ALD can be evaluated by ultrasound, CT, or MRI, there is still no imaging technique sufficient in the diagnosis of early-stage ALD. Of the current studies, epigenetic modulation plays a significant role in the development and progression of ALD. In this work, we evaluate whether BRDs play a vital role in the early-stage ALD using our new PET imaging probe of BET proteins, [¹¹C]CW22. PET/CT imaging of [¹¹C]CW22 and [¹⁸F]FDG was used to identify early-stage lesions of livers and brains in the mice model. We found that the average uptake values of livers and brains in early-stage ALD were significantly increased for [¹¹C]CW22 PET/CT imaging but only slightly changed in [¹⁸F]FDG PET/CT imaging. Consistently, we also found that BRD 3, 4 protein expression levels were significantly higher in the liver and brain tissues of early-stage ALD. Furthermore, through Pmod software, we found that [¹¹C]CW22 PET/CT uptakes in the brain stem, cerebellum, and midbrain were significantly up-regulated in the early-stage ALD. In conclusion, BRDs were important mediators of damage in early-stage ALD. [¹¹C]CW22 PET/CT imaging can detect the early-phase alcohol-induced damage of livers and brains, which will likely lead to human trials in the future.

Radiomics based on fluoro-deoxyglucose positron emission tomography predicts liver fibrosis in biopsy-proven MAFLD: a pilot study

Rationale: Since non-invasive tests for prediction of liver fibrosis have a poor diagnostic performance for detecting low levels of fibrosis, it is important to explore the diagnostic capabilities of other non-invasive tests to diagnose low levels of fibrosis. We aimed to evaluate the performance of radiomics based on ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) in predicting any liver fibrosis in individuals with biopsy-proven metabolic dysfunction-associated fatty liver disease (MAFLD). Methods: A total of 22 adults with biopsy-confirmed MAFLD, who underwent ¹⁸F-FDG PET/CT, were enrolled in this study. Sixty radiomics features were extracted from whole liver region of interest in ¹⁸F-FDG PET images. Subsequently, the minimum redundancy maximum relevance (mRMR) method was performed and a subset of two features mostly related to the output classes and low redundancy between them were selected according to an event per variable of 5. Logistic regression, Support Vector Machine, Naive Bayes, 5-Nearest Neighbor and linear discriminant analysis models were built based on selected features. The predictive performances were assessed by the receiver operator characteristic (ROC) curve analysis. Results: The mean (SD) age of the subjects was 38.5 (10.4) years and 17 subjects were men. 12 subjects had histological evidence of any liver fibrosis. The coarseness of neighborhood grey-level difference matrix (NGLDM) and long-run emphasis (LRE) of grey-level run length matrix (GLRLM) were selected to predict fibrosis. The logistic regression model performed best with an AUROC of 0.817 [95% confidence intervals, 0.595-0.947] for prediction of liver fibrosis. Conclusion: These preliminary data suggest that ¹⁸F-FDG PET radiomics may have clinical utility in assessing early liver fibrosis in MAFLD.

PET/SPECT Molecular Probes for the Diagnosis and Staging of Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a significant public health challenge afflicting approximately 1 billion individuals both in the Western world and in the East world. While liver biopsy is considered as gold standard in the diagnosis and staging of liver fibrosis, noninvasive imaging technologies, including ultrasonography, computed tomography, single-photon emission computed tomography (SPECT), magnetic resonance imaging, and positron emission tomography (PET) could offer more sensitive, comprehensive, and quantitative measurement for NAFLD. In this review, we focus on recent development and applications of PET/SPECT molecular probes that enable multispatial/temporal visualization and quantification of physiopathological progress at the molecular level in the NAFLD. We shall also discuss the limitations of current radioligands and future direction for PET/SPECT probe development.

In vivo confirmation of altered hepatic glucose metabolism in patients with liver fibrosis/cirrhosis by 18F-FDG PET/CT

OBJECTIVE

The aim of this study was to assess the value of ¹⁸F-FDG PET/CT for quantitative assessment of hepatic metabolism in patients with different stages of liver fibrosis/cirrhosis.

MATERIALS AND METHODS

¹⁸F-FDG PET/CT scans of 37 patients either with or without liver fibrosis/cirrhosis, classified according to the METAVIR score (F0-F4) obtained from histopathological analysis of liver specimen, were analyzed retrospectively and classified as follows: no liver fibrosis (F0, n = 6), mild liver fibrosis (F1, n = 11), advanced liver fibrosis (F2, n = 6), severe liver fibrosis (F3, n = 5), and liver cirrhosis (F4, n = 11). The liver-to-blood ratio (LBR, scan time corrected for a reference time of 75 min) was compared between patient groups.

RESULTS

Patients with liver fibrosis or cirrhosis (≥ F1; LBR 1.53 ± 0.35) showed a significant higher LBR than patients with normal liver parenchyma (F0, 1.08 ± 0.23; P = 0.004). In direct comparison, LBR increased up to the advanced stage of liver fibrosis (F2; 2.00 ± 0.40) and decreased until liver cirrhosis is reached (F4, 1.32 ± 0.14).

CONCLUSION

Functional changes in liver parenchyma during liver fibrosis/cirrhosis affect hepatic glucose metabolism and significantly differ between stages of liver fibrosis/cirrhosis, classified according to the METAVIR scoring system, as demonstrated by LBR quantification by ¹⁸F-FDG PET/CT.

Hepatic glucose uptake is increased in association with elevated serum γ-glutamyl transpeptidase and triglyceride

BACKGROUND

Subjects with fatty liver disease (FLD) can show increased hepatic 2-deoxy-2-((18)F)fluoro-D-glucose (FDG) uptake, but the role of hepatic inflammation has not been explored.

AIMS

We investigated whether hepatic inflammatory response, as implicated by elevated serum markers, is associated with increased liver FDG uptake in FLD.

METHODS

Liver sonography and FDG positron emission tomography was performed in 331 asymptomatic men with nonalcoholic FLD (NAFLD), 122 with alcoholic FLD (AFLD), and 349 controls. Mean standard uptake value (SUV) of liver FDG uptake was compared to cardiac risk factors and serum markers of liver injury.

RESULTS

Hepatic FDG mean SUV was increased in NAFLD (2.40 ± 0.25) and AFLD groups (2.44 ± 0.25) compared to controls (2.28 ± 0.26; both P < 0.001). Both FLD groups also had higher serum γ-glutamylranspeptidase (GGT), triglyceride (TG), hepatic transaminases, and LDL. High GGT and TG levels were independent determinants of increased FDG uptake for both FLD groups. Hepatic mean SUV significantly increased with high compared to low GGT for NAFLD (2.48 ± 0.28 vs. 2.37 ± 0.24), AFLD (2.51 ± 0.27 vs. 2.39 ± 0.23), and control groups (2.39 ± 0.22 vs. 2.26 ± 0.26). High TG increased hepatic mean SUV in AFLD and control groups. Furthermore, serum GGT and TG levels significantly correlated to hepatic mean SUV in all three groups.

CONCLUSIONS

Hepatic FDG uptake is closely associated with elevated TG and GGT regardless of the presence of FLD. Thus, inflammation response may play a major role in increased hepatic glucose uptake.