Prognostic value of CT attenuation and FDG uptake of adipose tissue in patients with pancreatic adenocarcinoma.

AIM: To investigate the prognostic significance of computed tomography (CT) attenuation and 2-[18F]-fluoro-2-deoxy-d-glucose (FDG) uptake in subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) for predicting overall survival (OS) in patients with pancreatic adenocarcinoma. MATERIALS AND METHODS: Data were collected retrospectively from 66 patients with pancreatic adenocarcinoma who had undergone pretreatment combined FDG positron-emission tomography (PET)/CT imaging and subsequent curative or palliative treatment. Metabolic parameters of primary tumour including total lesion glycolysis (TLG) and heterogeneity factor were measured. Volume, CT attenuation (attenuation), and FDG uptake of SAT and VAT were derived from PET/CT acquisitions. Survival analysis using Cox proportional hazard modelling was performed to assess the relationship between both attenuation and FDG uptake of fat tissue and OS. RESULTS: During follow-up, 33 patients (50%) died and the median OS was 12 months. There were significant positive correlations between attenuation and mean standardised uptake values of both SAT (p<0.001, r=0.697) and VAT (p<0.001, r=0.742). Attenuation and FDG uptake of adipose tissue were significantly associated with heterogeneity factor and T stage. Patients with high FDG uptake and attenuation of SAT and VAT had significantly worse OS than those with low values. On multivariate analysis, attenuation of SAT (p=0.047) and VAT (p=0.021), and FDG uptake of VAT (p=0.005) were correlated significantly with OS after adjusting for age, sex, body mass index, TNM stage, and TLG. CONCLUSIONS: CT attenuation of SAT and VAT, and FDG uptake of VAT significantly correlated with OS in patients with pancreatic adenocarcinoma, independent of TNM staging and TLG.

Evaluation of 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography in rat models with hepatocellular carcinoma with liver cirrhosis.

Liver cirrhosis is a predominant risk factor for hepatocellular carcinoma (HCC). However, the exact mechanism of the progression from cirrhosis to cancer remains unclear. The uptake of 2-[(18)F]-fluoro-2-deoxy-D-glucose ((18)F-FDG) is widely used as a marker of increased glucose metabolism to monitor the progression of cancer with positron emission tomography (PET)/computed tomography (CT). Here we investigated the feasibility of using (18)F-FDG PET/CT in the diethylnitrosamine (DEN) mediated experimental hepatocellular carcinoma model. Rats received weekly intraperitoneal injections of DEN for 16 weeks for induction of HCC. We recorded starting from 0 days or 0 weeks after the last DEN injection. The weight and survival rate of rats were then measured. Also, an (18)F-FDG PET scan and serum analysis were performed at minus 2, 0, plus 2, and plus 4 weeks after the last DEN injection. The body weight of rats was maintained between 350 g and 370 g during 14 and 20 weeks, and the rats were euthanized at 35 days after the last DEN injection. The serum levels of alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphate (ALP) were significantly higher at zero weeks after the last DEN injection. The (18)F-FDG uptake for the quantitative evaluation of HCC was done by measuring the region of interest (ROI). At minus two weeks after the last DEN injection, the ROI of rats had significantly increased compared to the normal group, in a time-dependent manner. These results suggest that FDG uptake serves as a good screening test to evaluate the feasibility of DEN-induced HCC.

Alteration of ictal and interictal perfusion in patients with paroxysmal kinesigenic dyskinesia.

Although previous cerebral blood flow studies have suggested that the basal ganglia or thalamus are involved in the pathogenesis of paroxysmal kinesigenic dyskinesia (PKD), the precise anatomic substrate or pathophysiological networks associated with PKD remain unclear. Here, ictal and interictal single photon emission computed tomography (SPECT) in 2 patients with idiopathic PKD compared to 6 age-matched normal controls and the perfusion findings of subtraction ictal SPECT co-registered to MRI (SISCOM) in 1 patient are reported. The interictal and ictal perfusion changes were different in each of the patients and there were no consistent anatomic substrates observed. 2 patients had significant perfusion changes in the left frontal/temporal cortices compared to controls, whereas the others showed an increased uptake of 99mTc-ethyl cysteinate dimer (ECD) in the left occipital area on subtraction SPECT imaging. The results of this study suggest that the pathophysiology of PKD cannot be simply explained by lesions of the basal ganglia or thalamus, and that other associated areas of the cortex are likely involved in these movement disorders.

Muscular sarcoidosis: Ga-67 scintigraphy and magnetic resonance imaging.

Ga-67 scintigraphy is helpful in the assessment of active extrapulmonary sarcoidosis. Muscular involvement of sarcoidosis is often asymptomatic or nonspecific, and laboratory examinations do not provide convincing evidence of muscular involvement. The authors report a case of muscular sarcoidosis detected by Ga-67 scintigraphy. In a patient who had fever and arthralgia of both knee joints, Ga-67 scintigraphy showed mediastinal and hilar involvement of sarcoidosis with unexpected extensive muscular uptake. Magnetic resonance imaging revealed in detail intramuscular infiltration of sarcoid granuloma. Ga-67 scintigraphy is useful in detecting inflammatory muscular involvement of sarcoidosis and other multiorgan involvement.