Positron-emission tomography for hepatocellular carcinoma:Current status and future prospects

Hepatocellular carcinoma(HCC)is one of the leading causes of cancer mortality worldwide.Various imaging modalities provide important information about HCC for its clinical management.Since positron-emission tomography(PET)or PET-computed tomography was introduced to the oncologic setting,it has played crucial roles in detecting,distinguishing,accurately staging,and evaluating local,residual,and recurrent HCC.PET imaging visualizes tissue metabolic information that is closely associated with treatment.Dynamic PET imaging and dual-tracer have emerged as complementary techniques that aid in various aspects of HCC diagnosis.The advent of new radiotracers and the development of immuno-PET and PET-magnetic resonance imaging have improved the ability to detect lesions and have made great progress in treatment surveillance.The current PET diagnostic capabilities for HCC and the supplementary techniques are reviewed herein.

Low glucose metabolism in hepatocellular carcinoma with GPC3 expression

AIM To investigate the relationship between glucose metabolism and glypican-3(GPc3)expression in hepatocellular carcinoma(Hcc).METHODSImmunohistochemical staining of pathological samples for GPc3 and glucose transporter 1(GLUT1),and whole-body ^(18)F-FDG PET/c T for measuring tumour glucose uptake were performed in 55 newly diagnosed Hcc patients.The maximum standard uptake value(s UVmax)and tumour-to-non-tumourous liver uptake(T/NT)ratio were used to quantify ^(18)F-FDG uptake.In vitro ^(18)F-FDG uptake assay of GPc3-expressing Hep G2 and non-GPc3-expressing RH7777 cel ls was used to examine the effect of GPc3 in cellular glucose metabolism.The relationships between GPc3 expression and ^(18)F-FDG uptake,GLUT1 expression,tumour differentiation,and other clinical indicators were analysed using spearman rank correlation,univariateand multiple logistic regression analyses.RESULTSPositive GPc3 expression was observed in 67.3%of Hcc patients,including 75.0%of those with well or moderately differentiated Hcc and 36.4%of those with poorly differentiated Hcc.There was an inverse relationship between GPc3 expression and s UVmax(Spearman correlation coefficient=-0.281,P=0.038)and a positive relationship between GLUT1 expression and sU Vmax(Spearman correlation coefficient=0.681,P<0.001)in patients with Hcc.Univariate analysis showed that two glucose metabolic parameters(sU Vmax and T/NT ratio),tumour differentiation,lymph node metastasis,and TNM stage were all significantly associated with GPc3 expression(P<0.05),whereas GLUT1 expression,sex,age,tumour size,intrahepatic lesion number,and distant metastasis showed no statistical association(P>0.05).Further multivariate analysis revealed that only the T/N ratio was significantly correlated with GPC3 expression in patients with Hcc(P<0.05).In vitro assay revealed that the uptake of ^(18)F-FDG in GPc3-expressing HepG2 cells was significantly lower than that of non-GPc3-expressing RH7777 cells(t=-20.352,P<0.001).CONCLUSIONThe present study demonstrated that GPc3 expression is inversely associated with glucose metabolism,suggesting that GPc3 may play a role in regulating glucose metabolism in Hcc.

^(18)F-FDG PET/CT in differentiating malignant from benign origins of obstructive jaundice

BACKGROUND： The various origins of obstructive jaundice make the diagnosis of the disease difficult. This study was undertaken to evaluate the role of 18F-FDG PET/CT in differentiating malignant from benign origins of obstructive jaundice and to quantify the added value of 18F-FDG PET/CT over conventional imaging（enhanced CT and/or MRI）.METHODS： Eighty-five patients with obstructive jaundice who underwent 18F-FDG PET/CT within 2 weeks after enhanced CT and/or MRI were reviewed retrospectively. All 18F-FDG PET/CT images were independently evaluated by 2 nuclear medicine physicians who were unaware of other imaging data; differences were resolved by consensus of the physicians. All conventional imaging interpretations, according to the medical records, were reviewed by 2 radiologists to determine the potential value. Final diagnoses were based on histological or surgical findings.RESULTS： Sixty-six patients were diagnosed with malignancies, and 19 patients with benign lesions. The maximum standardized uptake values for malignant and benign lesions causing biliary obstruction were 8.2±4.4 and 4.0±5.0, respectively（P〈0.05）. The sensitivity, specificity, and overall accuracy for differentiating malignant from benign origins with 18F-FDG PET/CT were 86.4%（57/66）, 73.7%（14/19）, and 83.5%（71/85）, respectively. 18F-FDG PET/CT in conjunction with conventional imaging changed the sensitivity, specificity, and overall accuracy of conventional imaging alone from 75.8%（50/66） to 95.5%（63/66）（P〈0.05）, 68.4%（13/19） to 57.9%（11/19）（P〉0.05）, and 74.1%（63/85） to 87.1%（74/85）（P〈0.05）, respectively.CONCLUSIONS： 18F-FDG PET/CT is of great value in differentiating malignant from benign origins of obstructive jaundice and is a useful adjuvant to conventional imaging. 18F-FDG PET/CT should be recommended for further etiological clarification.