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Brain dopamine neurotransmission is regulated by the dopamine transporter (DAT), which drives reuptake of extracellular dopamine into the presynaptic neurons. We hypothesized that the glucose loading dose would affect the striatal DAT availability. An i.v. bolus injection of 18F-FP-CIT was administered after infusion of low-dose glucose (300 mg/kg), high-dose glucose (600 mg/kg) or placebo (normal saline). The emission data were acquired over 90 min in 23 healthy male subjects. Substantial increases of binding potential (BPNDs) from ventral striatum (VST), caudate nucleus, and putamen were observed after low-dose glucose loading (+26.0, +87.0, and +37.8%) and after high-dose glucose loading (+10.4, +51.9, and +22.0%). BPNDs of the caudate nucleus and putamen showed significant differences (P= 0.0472 and 0.0221) after placebo, low-dose glucose, and high-dose glucose loading. BPNDs in the caudate nucleus and putamen after placebo, low-dose glucose, and high-dose glucose loading were positively intercorrelated with each other. In conclusion, striatal DAT changes after physiological glucose loading, but not after supraphysiological glucose loading in humans. DAT availabilities after placebo, low-dose glucose, high-dose glucose loading were correlated to each other in the caudate nucleus and putamen, but not in the VST. Therefore, sub-regional variability in DAT regulatory mechanisms mediated by insulin may exist in humans.

Purpose: The incidence of breast cancer has increased steadily. We performed a meta-analysis to assess the impact of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) on the management of breast cancer with respect to the detection of recurrence/metastasis after curative surgery. Methods: We performed systematic searches of the MEDLINE and EMBASE databases for English language publications. All published studies regarding the impact of PET on the management of patients with breast cancer with respect to the detection of recurrence/metastasis after curative surgery, such as mastectomy or lumpectomy, were searched. The proportion of management change (%), defined as the percentage of patients for whom management was changed after FDG PET among patients who underwent FDG PET, was calculated. Results: Thirteen studies, which included 982 patients, were included in this study. The impact of PET was evaluated based on the proportion of management change, and a pooled effect of 44.4% was noted. In the subgroup analyses for (1) equivocal/suspicious recurrence/metastasis on conventional imaging, (2) abnormal symptoms or physical examination, and (3) elevated tumor markers (n= 834), the pooled rate of management change was 45.9%. In patients with elevated tumor markers (n= 350) and in those who underwent PET for routine surveillance, the pooled rates of management change were 52.3% and 12.4%, respectively. Conclusions: 18F-FDG PET has a major impact on the management of patients with breast cancer after curative surgery. These findings suggest that 18F-FDG PET should be performed in patients with breast cancer in cases involving equivocal or suspicious recurrence/metastasis on conventional imaging or in cases involving elevated tumor markers during follow-up. However, this study does not support the routine use of 18F-FDG PET for surveillance in breast cancer.

ABSTRACTThis study investigated whether an optic neuropathy results in changes of brain glucose metabolism using 2-deoxy-2-F-18 fluoro-D-glucose (F-18 FDG) positron emission tomography (PET) scan. Optic nerves were crushed in the left eye of four male Sprague–Dawley rats, which were examined using F-18 FDG PET 7 days before and after surgery for a total of 5 weeks. We calculated the standardized uptake value ratio and analyzed relative changes in the visual cortex, thalamus, hypothalamus, and superior colliculus over time. The glucose metabolism in both visual cortices elevated after an optic nerve injury. A trend towards higher glucose metabolism, reaching significance 2 weeks following the procedure, was observed in the right visual cortical areas compared with those in the left hemisphere. The standardized uptake value ratios of both thalami significantly increased in 2 weeks as compared with the baseline. Other brain regions showed no significant changes. Traumatic optic neuropathy in rats causes asymmetrical elevation in brain glucose metabolism in the visual cortex, while the observed changes in the thalami as compared with baseline were similar in both hemispheres of the rat brain.

Purpose: We aimed to investigate inflammation indices based on preablation hematological parameter of the lymphocyte-to-monocyte ratio (LMR) to predict the clinical outcome in papillary thyroid cancer (PTC) patients with low- and intermediate-risk stratification. Methods: This retrospective study analyzed 772 patients with low- and intermediate-risk PTC who underwent total thyroidectomy followed by radioiodine therapy between July 2005 and July 2009 with a median of 10 years. Kaplan–Meier statistics were used to test differences in recurrence-free survival (RFS) between groups based on the optimal cutoff point of biomarkers identified using receiver operating characteristic curves. Results: With an optimal cutoff point of 7.05, 215 patients (29.8%) were classified as having low LMR and 557 patients (71.2%) were classified as having high LMR. High LMR was significantly associated with a prolonged RFS (hazard ratio [HR]: 2.048, 95% confidence interval [CI]: 1.062–4.359, p= 0.001). Multivariate analysis showed that low LMR (HR = 2.035, 95% CI: 1.011–4.095, p= 0.012), tumor size over 2 cm (HR = 2.762, 95% CI: 1.303–5.852, p= 0.008), and high preablative simulated thyroglobulin level over 10 ng/ml (HR = 7.826, 95% CI: 2.353–26.033, p< 0.001) were independent prognostic markers for worse RFS in the enrolled PTC patients. Conclusions: LMR at the time of radioiodine therapy has comparable predictor for the clinical outcome with both tumor size and preablative simulated thyroglobulin level in low- to intermediate-risk PTC patients.

We spend about one-third of our lives either sleeping or attempting to sleep. Therefore, the socioeconomic implications of sleep disorders may be higher than expected. However, the fundamental mechanisms and functions of sleep are not yet fully understood. Neuroimaging has been utilized to reveal the connectivity between sleep and the brain, which is associated with the physiology of sleep. Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging studies have become increasingly common in sleep research. Recently, significant progress has been made in understanding the physiology of sleep through neuroimaging and the use of various radiopharmaceuticals, as the sleep–wake cycle is regulated by multiple neurotransmitters, including dopamine, adenosine, glutamate, and others. In addition, the characteristics of rapid eye and non-rapid eye movement sleep have been investigated by measuring cerebral glucose metabolism. The physiology of sleep has been investigated using PET to study glymphatic function as a means to clear the amyloid burden. However, the basic mechanisms and functions of sleep are not yet fully understood. Further studies are needed to investigate the effects and consequences of chronic sleep deprivation, and the relevance of sleep to other diseases.

We examined the effect of TSH-suppressive dose of LT4 on changes in body composition and proinflammatory markers in ovariectomized rats. Bilateral ovariectomy (OVX) and sham operations (Sham) were performed in female Sprague–Dawley rats at 7 weeks of age. Rats were divided as Sham (n = 6), Sham + LT4 (n = 6), OVX (n = 8), and OVX + LT4 (n = 8). Eight weeks after surgery, the body composition was analyzed using Dual energy X-ray Absorptiometry. The percentage of gain of fat mass and lean mass of whole body, body trunk and extremities were evaluated. Serum TSH, cholesterol, creatinine kinase (CK), C-reactive peptide, interleukin (IL)-1β, IL-4, IL-6, IL-10, monocyte chemoattractant protein-1 and tumor necrosis factor-αwere compared among the four experimental groups. The middle third of soleus muscle was analyzed with cross-sectional area (CSA), Feret’s diameter (FD) and an area of interstitial space. A Kruskal–Wallis test was used and post-hoc analysis was performed using the GRAPHPAD PRISM (ver 8.0, GraphPad Software, Inc.) The fat mass, but not lean mass, was significantly increased in the OVX groups compared with Sham groups, regardless of LT4 treatment. CSA, FD and the area of interstitium were elevated in OVX groups and increased with LT4 treatment. OVX + LT4 group showed the most deteriorated muscle with the lowest serum level of CK and highest level of IL-6.

Objectives: To report a rare clinical presentation of an acellular dermal matrix (ADM) used during lateral temporal bone resection mimicking recurrence of cancer of external auditory canal (EAC) on positron emission tomography/computed tomography (PET/CT) 9 months after surgery.Methods: Case report and literature review.Results: A 71-year-old woman underwent lateral temporal bone resection 9 months earlier for management of squamous cell carcinoma of the EAC. She exhibited recurrence of the tumor on 18F-FDG PET/CT with an intense uptake value (SUVmax12.8) at the operated site. Exploration was conducted as the location of the lesion was unfavorable to perform biopsy. However, histopathologic evaluation revealed that the lesion was the ADM implanted during surgery.Conclusions: Care should be taken when using an ADM during malignant tumor surgery if the site of surgery is not conducive for fine needle aspiration or biopsy.

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The purpose of the current study was to investigate the diagnostic performance of F-18 Fluorocholine (FCH) positron emission tomography/computed tomography (PET/CT) for localization of hyperfunctioning parathyroid gland in patients with hyperparathyroidism (HPT) through a systematic review and meta-analysis. The MEDLINE/PubMed and EMBASE database, from the earliest available date of indexing through April 30, 2018, were searched for studies evaluating the diagnostic performance of F-18 FCH PET/CT for localization of hyperfunctioning parathyroid gland in patients with HPT. We determined the sensitivities and specificities across studies, calculated positive and negative likelihood ratios (LR+ and LR−), and constructed summary receiver operating characteristic curves. Across eight studies (272 patients), the pooled sensitivity for F-18 FCH PET/CT was 0.90 (95% CI, 0.86–0.94) without heterogeneity (I2= 7.1) and a pooled specificity of 0.94 (95% CI, 0.90–0.96) with heterogeneity (I2= 79.8). Likelihood ratio (LR) syntheses gave an overall positive likelihood ratio (LR+) of 5.3 (95% CI, 1.2–24.3) and negative likelihood ratio (LR−) of 0.15 (95% CI, 0.08–0.29). The pooled diagnostic odds ratio (DOR) was 38 (95% CI, 8–174). Hierarchical summary receiver operating characteristic (ROC) curve indicates that the areas under the curve were 0.9492 (SE, 0.0215). In meta-regression analysis, no definite variable was the source of the study heterogeneity. The current meta-analysis showed the high sensitivity and specificity of F-18 FCH PET/CT for localization of hyperfunctioning parathyroid gland. At present, the literature regarding the use of F-18 FCH PET/CT for localization of hyperfunctioning parathyroid gland remains still limited; thus, further large multicenter studies would be necessary to substantiate the diagnostic accuracy of F-18 FCH PET/for localization of hyperfunctioning parathyroid gland in patients with HPT.

This study aimed to examine the discrepancy in osteoporosis diagnoses between central quantitative computed tomography (cQCT) and dual-energy X-ray absorptiometry (DXA) and evaluated correlations among volumetric bone mineral density (vBMD), areal bone mineral density (aBMD), and trabecular bone score(TBS) in postmenopausal women who were undergoing TSH suppressive therapy.

Obesity, an increasingly common problem in modern societies, results from energy intake chronically exceeding energy expenditure. This imbalance of energy can be triggered by the internal state of the caloric equation (homeostasis) and non-homeostatic factors, such as social, cultural, psychological, environmental factors or food itself. Nowadays, positron emission tomography (PET) radiopharmaceuticals have been examined to understand the cerebral control of food intake in humans. Using 15O–H2PET, changes in regional cerebral blood flow (rCBF) coupled to neuronal activity were reported in states of fasting, satiation after feeding, and sensory stimulation. In addition, rCBF in obese subjects showed a greater increase in insula, the primary gustatory cortex. 18F–fluorodeoxyglucose PET showed higher metabolic activity in postcentral gyrus of the parietal cortex and lower in prefrontal cortex and anterior cingulate cortex in obese subjects. In addition, dopamine receptor (DR) PET demonstrated lower DR availability in obese subjects, which might lead to overeating to compensate. Brain PET has been utilized to reveal the connectivity between obesity and brain. This could improve understanding of obesity and help develop a new treatment for obesity.

Several staging systems have been developed to predict the risk of mortality in patients with differentiated thyroid cancer (DTC). However, none of them have been shown to be clearly superior to the other. We compared the patient outcome predictability of recently revised staging systems predictability of patient outcome using data from The Cancer Genome Atlas. To set a comparison among American Joint Committee on Cancer (AJCC)/Union for International Cancer Control (UICC) staging 7th, 8th editions, American Thyroid Association guidelines 2009 and 2015, concordance index (c-index), Akaike information criterion (AIC), Bayesian information criterion (BIC), and Brier score were applied to quantify the predictive ability of a survival model, to select the statistical model, and to measure the accuracy of probabilistic predictions. A total of 457 patients with papillary thyroid cancer having a mean age of 45.9 years were included in this study (120 males, 337 females). Among these patients, 43 (9.4%) experienced recurrence/progression during the follow-up (591.2 ± 833.5 months). Among the models used, the AJCC/UICC 8th edition, which showed the highest c-index and lowest AIC, BIC, and Brier score, was identified as the best among the models used. AJCC/UICC 8th edition predicted patient outcome more accurately than the other staging systems.

Previously published studies showed that the standard tumor-to-blood standardized uptake value (SUV) ratio (SUR) was a more accurate prognostic method than tumor maximum standardized uptake value (SUVmax). This study evaluated and compared prognostic value of positron emission tomography (PET) parameters and normalized value of PET parameters by blood pool SUV in non-small-cell lung cancer (NSCLC) patients who received curative surgery. Seventy-seven patients who underwent curative resection for NSCLC between January 2010 to December 2013 were enrolled in this study. 18Fluorine-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) was performed before surgery. The mean standardized uptake value (SUVmean), SUVmax, metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of each lesion was measured, on the workstation. SURmean, SURmax, and TLGSUR were calculated by dividing each of them by descending aorta SUVmean. Cox proportional hazards regression was used to analyze the effect of age, sex, pathological parameters, and PET parameters on recurrence and death. In Cox regression analysis, N stage predicted for both recurrence (p< 0.0001) and death (p< 0.0001). SURmaxpredicted recurrence (p= 0.0014), not death. Area under the receiver operating characteristic curve of SURmaxwas 0.759 with cutoff value 4.004. However, SUVmax, SUVmean, MTV, TLG, SURmean, and TLGSUR predicted neither recurrence nor death. Among PET parameters, SURmaxwas the independent predictor of recurrence in NSCLC patients who received curative surgery. N stage was the independent prognostic factor for both recurrence and death. Both parameters could be used to stratify the risk of NSCLC patients.

Positron emission tomography (PET) has come to the practice of oncology. It is known that 18F-fluorodeoxyglucose (FDG) PET is more sensitive for the assessment of treatment response than conventional imaging. In addition, PET has an advantage in the use of quantitative analysis of the study. Nowadays, various PET parameters are adopted in clinical settings. In addition, a wide range of factors has been known to be associated with FDG uptake. Therefore, there has been a need for standardization and harmonization of protocols and PET parameters. We will introduce PET parameters and discuss major issues in this review.

The objective of this study was to investigate the relationship between diversity of 18F-fluorodeoxyglucose (18F-FDG) uptake of primary tumor in positron emission tomography (PET) and various clinicopathologic factors in breast cancer of same pathologic T1, T2 stage. A total of 258 patients with invasive ductal breast cancer were enrolled in this study. All patients underwent 18F-FDG PET-CT before surgery. Patients were divided into two groups according to tumor size based on the pathologic T stage, and maximum standardized uptake value (SUVmax) of 2.5, respectively. On the univariate analysis, estrogen receptor (ER), tumor size, lymphovascular invasion, p53, pathologic N status (pN) and Nottingham tumor grade (NG) were associated with high SUVmax in T1 and T2 breast cancer. On the multivariate logistic regression, tumor size and NG remained significant variables dividing high and low SUVmax. In the T1 group, ER, p53 and NG were significantly associated with high SUVmax on the univariate analysis. In this group, p53 and NG remained significant variables for dividing high and low SUVmax on the multivariate logistic regression. In the T2 group, only NG was associated with high SUVmax on the univariate analysis. NG showed an association with 18F-FDG uptake in both T1 and T2 breast cancer independently; however, p53 in T1 breast cancer.

We aimed to evaluate the diagnostic performance of measuring the concentration of thyroglobulin (Tg) in the washout fluid of the needle aspiration (FNA-Tg). We performed a systematic search of MEDLINE (inception to October 2013) and EMBASE (inception to October 2013) for English publications using keywords “thyroid”, “aspiration”, “washout”, and “thyroglobulin”. All searches were limited to human studies. We included studies of FNA-Tg measurement in the washout fluid rinsed with 1 ml of normal saline. Eight studies including 843 lymph nodes (LNs) were eligible for this study. The pooled sensitivity and specificity of preoperative studies are 0.89 [95 % CI 0.82–0.95], 0.60 [0.49–0.70], and those of postoperative studies are 1.0 [0.83–1.0], 1.0 [0.92–1.0]. To determine best cutoffs from each preoperative and postoperative study, the distance between the point (0, 1) and each observed cutoff values (1-specificity, sensitivity) was calculated, and the distance is minimal when the cutoff value of 32.04 for preoperative studies and of 0.9 for postoperative one are selected. FNA-Tg can be used for both preoperative and postoperative evaluation of LN metastasis. Although the cutoff values for the FNA-Tg has not been standardized, preoperative values of 32.04 ng/ml and postoperative values of 0.9 ng/ml are recommended for identifying neck LN metastasis

The prevalence and risk of malignancy in thyroid incidentalomas has been investigated in previous studies; however, these studies have not looked at the characteristics of incidental thyroid cancer (ITC) detected by fluorine-18 fluorodeoxyglucose PET. Therefore, we aimed to assess the clinicopathologic features of ITC.

Concurrent inflammation or anemia at the time of PETcomputed tomography (CT) could be one of several causes of diffuse splenic 18F-fluorodeoxyglucose (18F-FDG) uptake. In this study, we focused on cytokines to investigate interactions during this phenomenon and clarify the significance of splenic 18F-FDG uptake in PETCT.

Abstract: Purpose: We aimed to evaluate the relation between visceral fat volume and fluorodeoxyglucose (FDG) uptake of the liver measured by maximum or mean standardized uptake value. Methods: We retrospectively analyzed 96 consecutive records of positron emission tomography/computed tomography (PET/CT) performed for cancer screening between May 2011 and December 2011. Subjects were divided into 2 groups according to Hounsfield unit (HU) of the liver comparing with that of the spleen. The control group (20 women, 56 men) demonstrating HU of the liver equal or greater than that of the spleen included 76 patients, while the fatty liver group (2 women, 18 men) showing HU of the liver less than that of the spleen included 20 patients. We compared FDG uptake of the liver and visceral fat volume between two groups. We evaluated correlation of hepatic FDG uptake measured by maximum or mean standardized uptake value (SUV) with visceral fat volume and attenuation. Results: The fatty liver disease group showed higher aspartate aminotransferase (AST)of (24.42 ± 7.22, p = 0.012), alanine aminotransferase (ALT) of (25.16 ± 11.68, p = 0.001), body mass index (BMI) of (24.58 ± 3.29, p = 0.021), and visceral fat volume (3063.53 ± 1561.43, p = 0.011) than the control group. There were no statistically significant differences of mean standardized uptake value of the liver (liver SUVmean) (2.73 ± 0.19, p = 0.723), maximum standardized uptake value of the liver (liver SUVmax) (3.39 ± 0.53, p = 0.8248) and liver SUVmean/spleen SUVmean (1.13 ± 0.10, p = 0.081) between the two groups. Strong correlations were shown between liver SUVmean and BMI (r = 0.609, p < 0.001) and between liver SUVmean and visceral fat volume (r = 0.457, p < 0.001). Liver SUVmax was also strongly correlated with BMI (r = 0.622, p = 0.001) and visceral fat volume (r = 0.547, p < 0.001). There was no significant association of mean attenuation value of the liver (liver HUmean) with liver SUVmean (r = -0.003, p = 0.979) or liver SUVmax (r = -0.120, p = 0.244). Conclusion: Hepatic FDG uptake quantified as SUVmean or SUVmax is not correlated with hepatic steatosis but with visceral fat volume in cancer screening.

The aim of this study was to evaluate the usefulness of the tumor burden as characterized by the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) measured by F-18 fluoro-2-deoxyglucose (F-18 FDG) PET-computed tomography (CT) in predicting recurrence-free survival (RFS) and overall survival (OS) in surgically resected non-small-cell lung cancer (NSCLC) patients.

The aim of this study was to investigate whether diffuse increased splenic fluorodeoxyglucose (FDG) uptake may be an indirect sign of an acute pyogenic cause of infectious spondylitis (IS).

Stomach cancer is one of malignancies that may result in pulmonary tumor embolism. Pulmonary tumor embolism commonly presents with dyspnea and cor pulmonale signs. We report serial observations of pulmonary tumor embolism with 18F-FDG PET/CT. 18F-FDG PET/CT scan showed chronological changes of FDG uptake in both lung fields.

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