Incremental value of amyloid PET in a tertiary memory clinic setting in China.

INTRODUCTION: The objective of this study is to investigate the incremental value of amyloid positron emission tomography (Aß-PET) in a tertiary memory clinic setting in China. METHODS: A total of 1073 patients were offered Aß-PET using 18F-florbetapir. The neurologists determined a suspected etiology (Alzheimer's disease [AD] or non-AD) with a percentage estimate of their confidence and medication prescription both before and after receiving the Aß-PET results. RESULTS: After disclosure of the Aß-PET results, etiological diagnoses changed in 19.3% of patients, and diagnostic confidence increased from 69.3% to 85.6%. Amyloid PET results led to a change of treatment plan in 36.5% of patients. Compared to the late-onset group, the early-onset group had a more frequent change in diagnoses and a higher increase in diagnostic confidence. DISCUSSION: Aß-PET has significant impacts on the changes of diagnoses and management in Chinese population. Early-onset cases are more likely to benefit from Aß-PET than late-onset cases. HIGHLIGHTS: Amyloid PET contributes to diagnostic changes and its confidence in Chinese patients. Amyloid PET leads to a change of treatment plans in Chinese patients. Early-onset cases are more likely to benefit from amyloid PET than late-onset cases.

Effects of constraint-induced movement therapy on brain glucose metabolism in a rat model of cerebral ischemia: a micro PET/CT study.

PURPOSE: Constraint-induced movement therapy (CIMT) can improve motor functions in stroke patients and ischemic rats. This study examined the effect of CIMT in ischemic rats using positron emission tomography (PET). METHODS: We used middle cerebral artery occlusion (MCAO) procedure to induce cerebral ischemia in rats. Male rats were divided into a negative control group (Normal, n = 4), a sham-operated group (Sham, n = 6), an ischemic group (Control, n = 6) and an ischemic CIMT-treated group (CIMT, n = 6). CIMT started at postoperative day 8 (d8) and lasted for 2 weeks. We utilized 2-[18F]-fluoro-2-deoxy-D-glucose (18F-FDG) micro PET/CT imaging to evaluate glucose metabolism in different brain regions at baseline, before, and after treatment, respectively. RESULTS: CIMT improved behavioral performance in the ischemic CIMT group. At the end of treatment, the CIMT group showed lower standardized uptake values (SUVs) in the ipsilateral cingulate, motor and somatosensory cortex, respectively; as well as the anterodorsal hippocampus compared to the Control group (1.80% ± 0.10% vs. 1.92% ± 0.08%, 1.32% ± 0.14% vs. 1.48% ± 0.09%, 1.18% ± 0.14% vs. 1.42% ± 0.15%, 1.68% ± 0.09% vs. 1.79% ± 0.06%, P < 0.05). We also observed higher SUVs in the acbcore shell and cortex insular of the contralateral hemisphere compared to the Control group (2.07% group in the acbcore shell and cortex insular of contralateral P < 0.05). CONCLUSION: CIMT improved behavioral outcomes in cerebral ischemic rats and this effect can be attributed to increased glucose utilization in the contralateral hemisphere.

The value of 18F-FDG positron emission tomography/computed tomography on the pre-operative staging and the management of patients with pancreatic carcinoma.

BACKGROUND/AIMS: To evaluate the value of FDG-PET/CT on the pre-operative staging of pancreatic cancer and its impact on clinical management. METHODOLOGY: From December 2006 to January 2013, data of pancreatic carcinoma patients who underwent surgical treatment at our center was collected retrospectively. MDCT and FDGPET/CT were used separately to diagnose and stage the tumor. Pre-operation staging by MDCT with chest x-ray and by FDG-PET/CT was compared according to the final pathological staging. RESULTS: A total of 79 histologically proven pancreatic cancer patients were enrolled in this study. FDG-PET/CT was more accurate in the detection of tumor (PET/CT vs. MDCT: 93.67% vs. 88.61%, p=0.402). The SE (60.00% vs. 24.00%, p=0.01) and accuracy (87.81% vs. 76.83%, p=0.015) of PET/CT to detect distant metastasis is significantly higher than those of MDCT. FDG-PET/CT also showed advantage over CT in the detection of metastatic lymph nodes (52.83% vs. 16.98%, p<0.001; accuracy: 66.67% vs. 41.33, p=0.002). The extra staging information PET/CT provided could have skipped eight patients (10.13%) of unnecessary surgical exploration. CONCLUSION: FDG-PET/CT is an important staging procedure and helps to make the clinical decision for the patients with pancreatic carcinoma.

Brain amyloid-ß deposition associated functional connectivity changes of ultra-large structural scale in mild cognitive impairment.

In preclinical Alzheimer's disease, neuro-functional changes due to amyloid-ß (Aß) deposition are not synchronized in different brain lobes and subcortical nuclei. This study aimed to explore the correlation between brain Aß burden, connectivity changes in an ultra-large structural scale, and cognitive function in mild cognitive impairment. Participants with mild cognitive impairment were recruited and underwent florbetapir (F18-AV45) PET, resting-state functional MRI, and multidomain neuropsychological tests. AV-45 standardized uptake value ratio (SUVR) and functional connectivity of all participants were calculated. Of the total 144 participants, 72 were put in the low Aß burden group and 72 in the high Aß burden group. In the low Aß burden group, all connectivities between lobes and nuclei had no correlation with SUVR. In the high Aß burden group, SUVR showed negative correlations with the Subcortical-Occipital connectivity (r=-0.36, P = 0.02) and Subcortical-Parietal connectivity (r=-0.26, P = 0.026). Meanwhile, in the high Aß burden group, SUVR showed positive correlations with the Temporal-Prefrontal connectivity (r = 0.27, P = 0.023), Temporal-Occipital connectivity (r = 0.24, P = 0.038), and Temporal-Parietal connectivity (r = 0.32, P = 0.006). Subcortical to Occipital and Parietal connectivities had positive correlations with general cognition, language, memory, and executive function. Temporal to Prefrontal, Occipital, and Parietal connectivities had negative correlations with memory function, executive function, and visuospatial function, and a positive correlation with language function. In conclusion, Individuals with mild cognitive impairment with high Aß burden have Aß-related bidirectional functional connectivity changes between lobes and subcortical nuclei that are associated with cognitive decline in multiple domains. These connectivity changes reflect neurological impairment and failed compensation.

Analysis of positron emission tomography hypometabolic patterns and neuropsychiatric symptoms in patients with dementia syndromes.

AIMS: To estimate the proportions of specific hypometabolic patterns and their association with neuropsychiatric symptoms (NPS) in patients with cognitive impairment (CI). METHODS: This multicenter study with 1037 consecutive patients was conducted from December 2012 to December 2019. 18 F-FDG PET and clinical/demographic information, NPS assessments were recorded and analyzed to explore the associations between hypometabolic patterns and clinical features by correlation analysis and multivariable logistic regression models. RESULTS: Patients with clinical Alzheimer's disease (AD, 81.6%, 605/741) and dementia with Lewy bodies (67.9%, 19/28) mostly had AD-pattern hypometabolism, and 76/137 (55.5%) of patients with frontotemporal lobar degeneration showed frontal and anterior temporal pattern (FT-P) hypometabolism. Besides corticobasal degeneration, patients with behavioral variant frontotemporal dementia (36/58), semantic dementia (7/10), progressive non-fluent aphasia (6/9), frontotemporal lobar degeneration and amyotrophic lateral sclerosis (3/5), and progressive supranuclear palsy (21/37) also mostly showed FT-P hypometabolism. The proportion of FT-P hypometabolism was associated with the presence of hallucinations (R = 0.171, p = 0.04), anxiety (R = 0.182, p = 0.03), and appetite and eating abnormalities (R = 0.200, p = 0.01) in AD. CONCLUSION: Specific hypometabolic patterns in FDG-PET are associated with NPS and beneficial for the early identification and management of NPS in patients with CI.

Non-linear Character of Plasma Amyloid Beta Over the Course of Cognitive Decline in Alzheimer's Continuum.

Plasma amyloid-ß (Aß) was associated with brain Aß deposition and Alzheimer's disease (AD) development. However, changes of plasma Aß over the course of cognitive decline in the Alzheimer's continuum remained uncertain. We recruited 449 participants to this study, including normal controls (NC), subjective cognitive decline (SCD), mild cognitive impairment (MCI), AD, and non-AD dementia. All the participants underwent plasma Aß42, Aß40, and t-tau measurements with single-molecule array (Simoa) immunoassay and PET scan with 18F-florbetapir amyloid tracer. In the subgroup of Aß-PET positive, plasma Aß42 and Aß42/Aß40 ratio was significantly lower in AD than NC, SCD and MCI, yet SCD had significantly higher levels of plasma Aß42 than both NC and MCI. In the diagnostic groups of MCI and dementia, participants with Aß-PET positive had lower plasma Aß42 and Aß42/40 ratio than participants with Aß-PET negative, and the increasing levels of plasma Aß42 and Aß42/40 ratio indicated lower risks of Aß-PET positive. However, in the participants with SCD, plasma Aß42 and Aß40 were higher in the subgroup of Aß-PET positive than Aß-PET negative, and the increasing levels of plasma Aß42 and Aß40 indicated higher risks of Aß-PET positive. No significant association was observed between plasma Aß and Aß-PET status in normal controls. These findings showed that, in the continuum of AD, plasma Aß42 had a significantly increasing trend from NC to SCD before decreasing in MCI and AD. Furthermore, the predictive values of plasma Aß for brain amyloid deposition were inconsistent over the course of cognitive decline.

Amyloid PET in Dementia Syndromes: A Chinese Multicenter Study.

Cerebral ß-amyloid deposits and regional glucose metabolism assessed by PET are used to distinguish between Alzheimer disease (AD) and other dementia syndromes. In the present multicenter study, we estimated the prevalence of ß-amyloid deposits on PET imaging in a wide variety of dementia syndromes and mild cognitive impairment (MCI) within a memory clinic population. Methods: Of the 1,193 consecutive patients with cognitive impairment (CI) who received 1 11C-PIB PET or 18F-AV45 PET or both 11C-PIB PET and 18F-AV45 PET, 960 were diagnosed with AD, 36 with frontotemporal dementia (FTD), 5 with dementia with Lewy bodies, 144 with MCI, 29 with vascular dementia, 4 with corticobasal syndrome, and 15 with unclassifiable dementia. Baseline clinical diagnoses were independently established without access to PET imaging results. Apolipoprotein E (ApoE) genotype analysis was performed on CI patients and 231 sex- and age-matched controls. Results: Of the 1,193 CI patients, 860 (72.1%) were amyloid-positive. The prevalence of amyloid positivity in AD and MCI patients was 86.8% (833/960) and 9.7% (14/144), respectively. In FTD patients, the prevalence of ß-amyloid deposits was 5.6% (2/36). In the 4 corticobasal syndrome patients, 2 were amyloid-positive. Three of the 5 patients with dementia with Lewy bodies showed amyloid positivity, as did 6 of the 29 vascular dementia (20.7%) patients. The ApoEε4 allele frequency was significantly increased in amyloid-positive CI patients (30.5%) as compared with other amyloid-negative CI patients (14%) or controls (7.3%). Conclusion: Amyloid imaging may potentially be the most helpful parameter for differential diagnosis in dementia, particularly to distinguish between AD and FTD. Amyloid PET can be used in conjunction with the ApoEε4 allele genetic risk test for amyloid deposits.

Brain Amyloid-ß Deposition and Blood Biomarkers in Patients with Clinically Diagnosed Alzheimer's Disease.

Brain amyloid-ß (Aß) deposition is a hallmark to define Alzheimer's disease (AD). We investigated the positive rate of brain amyloid deposition assessed with 11C-Pittsburgh compound (PiB)-PET and blood Aß levels in a cohort of probable AD patients who were diagnosed according to the 1984 NINCDS-ADRDA criteria. Eighty-four subjects with a clinical diagnosis of probable AD dementia, amnestic mild cognitive impairment (MCI), and cognitively normal (CN) status were subjected to PiB-PET and 18F-fluorodeoxyglucose (FDG)-PET scans. Plasma biomarkers of Aß42, Aß40, and T-tau were measured using single molecule array technology. The positive rate of PiB-PET, the associations between PiB-PET status and FDG-PET, plasma biomarkers, and clinical manifestations were analyzed. PiB-PET was positive in 77.36% of probable AD patients, 31.80% of MCI patients, and 0 of NC. Plasma Aß42/Aß40 ratio was associated with PiB-PET, the ROC curve analysis revealing an AUC of 0.77 (95% CI: 0.66-0.87), with a sensitivity of 82% and specificity of 64%. Some clinical manifestations were associated with PiB-PET imaging. Our findings indicate that only three-fourths of patients diagnosed with probable AD fit the pathological criteria, suggesting that we should be cautious regarding the accuracy of AD diagnosis when no biomarker evidence is available in our clinical practice.

18F-FP-CIT PET imaging and SPM analysis of dopamine transporters in Parkinson's disease in various Hoehn & Yahr stages.

To investigate the usefulness of 18F-FP-CIT PET for assessing the severity of Parkinson's disease (PD) at various clinical stages, 41 patients with PD were divided into early (Hoehn&Yahr I-II, n = 23) and advanced (Hoehn & Yahr III-IV, n = 18) subgroups. 18F-FP-CIT PET was performed in these patients and 12 normal subjects. 18F-FP-CIT uptake in striatal subregions and its correlation with UPDRS were first evaluated by ROI analysis, and between-group differences were also analyzed by Statistical Parametric Mapping (SPM). Our results showed that striatal 18F-FP-CIT binding were significantly reduced to 70.9% (caudate), 46.8% (anterior putamen) and 24.0% (posterior putamen) in early PD compared with that of the control, and to 52.0%, 34.5% and 16.5% correspondingly in advanced PD, respectively. There was significant negative correlation between total motor UPDRS score of all parkinsonian patients and 18F-FP-CIT uptake in caudate nucleus (r = -0.53, p < 0.001), anterior putamen (r = -0.53, p < 0.001) and posterior putamen (r = -0.61, p < 0.001). SPM comparison of 18F-FP-CIT uptake between early or advanced PD and the control group showed significant decline in striatum, predominantly localized on the contralateral side and in the dorsal-posterior putamen. These results indicate that 18F-FP-CIT PET can serve as a suitable biomarker to represent the severity of PD in early and advanced stages.

[Malignant tumor with false negative 18F-FDG PET image].

OBJECTIVE: To investigate the FDG uptake characteristics, the factors affecting 18F-FDG uptake and the extra CT diagnostic value of 18F-FDG PET/CT scan in the malignant tumor with false negative 18F-FDG PET image. METHODS: The data of PET/CT image in 17 patients with various kinds of cancers were reviewed and analyzed by visual observation and semi-quantity analysis ( SUV). The results were compared with the CT and histopathological diagnosis, respectively. RESULTS: Of 6 well-differentiated HCC patients confirmed by histopathological diagnosis, one had two lesions in the right lobe of the liver. One of these two lesions showed low FDG uptake on 18F-FDG PET scan and low density on CT scan. The other one was not shown on either 18F-FDG PET or plain CT scan. But on enhanced CT scan, these two lesions were found to be inhomogeneous with high density at arterial phase. The false negative 18F-FDG PET images of one gastric signet ring cell carcinoma in the gastric fundus with right adnexa metastasis, 3 renal cell carcinoma, one greater omentum and peritoneal metastatic adenocarcinoma and one well-differentiated prostate cancer were caused by normal physical uptake in the digestive tract or FDG retention in the urinary system due to normal excretion. The size of three metastases was smaller than or equal to 1 cm in diameter, however, two primary lesions of these metastases showed high FDG uptake and only one was negative on either 18F-FDG PET or CT scan. In this series, 68.8% of the primary tumors and 66.7% of metastases were found to show abnormal density on CT scan, and 31. 2% of the primary tumors and 33. 3% of metastases were not detectable on either PET or CT images. CONCLUSION: False negative 18F-FDG PET in malignant tumor may be correlated with the pathologic type, differentiation degree and the lesion size. Combining CT information with PET or paying attention to the scan methods during 8 F-FDG PET examination may reduce the rate of false negative 18F-FDG PET diagnosis in various kinds of malignant tumors.

Expression of Glut-1 and HK-II in Pancreatic Cancer and Their Impact on Prognosis and FDG Accumulation.

OBJECTIVE: The purpose of this article is to analyze the expression of Glut-1 and HK-II, the association between their expression and 18F-FDG accumulation in pancreatic cancer. METHODS: Fifty patients with histologically proven pancreatic cancer were included in this preliminary study, all of whom received 18F-FDG PET/CT performance before surgery. Immunohistochemical staining of tumor tissue and adjacent normal tissue was performed for Glut-1 and HK-II. By combining proportions and intensity of immunochemical staining, we obtained the modified immunohistological scores for Glut-1 and HK-II respectively. The relationship between expression of Glut-1, HK-II and series of parameters was analyzed, i.e. clinicopathological characteristics, prognosis of patients and SUVmax of PET-CT. RESULTS: Compared with normal tissue, the Glut-1 and HK-II expression in pancreatic cancer tissue was significantly increased (P<.001). There was no correlation between expression of Glut-1, HK-II and age, gender, tumor size, tumor location, tumor histological type, tumor differentiation, the nerve infiltration, vascular invasion, local infiltration, lymph node metastasis or tumor staging in pancreatic cancer (P>.05). During the follow-up period, the survival curves of low Glut-1 group and high Glut-1 group were statistically different (P=.049). Multivariate analysis (Cox regression) revealed that Glut-1 expression was not associated with mortality (P>.05). No statistical difference was found in the survival curves of negative HK-II group and positive HK-II group (P=.545). There was no correlation between 18F-FDG uptake and expression of Glut-1 and HK-II(P>.05). CONCLUSION: The Glut-1 and HK-II expression in pancreatic cancer tissue was significantly increased. There was no correlation between expression of Glut-1, HK-II and clinicopathological characteristics, prognosis and 18F-FDG uptake.

Analysis of glucose metabolism of (18)F-FDG in major depression patients using PET imaging: Correlation of salivary cortisol and α-amylase.

Current diagnosis of Major depressive disorder (MDD) depends on its clinical symptoms, not on the results of any laboratory examinations. Establishing biological markers for diagnosis of MDD is one of the most important problems to be solved in psychiatry practice. MDD patients (n=8) and a healthy control group (n=8) were recruited in this study. Hamilton Depression Rating Scale (HAM-D) assessments were completed and saliva samples were collected for assessments of salivary cortisol and salivary α-amylase (sAA). PET examination was performed. Salivary cortisol and sAA in the MDD patients group were significantly higher than the healthy control group (P<0.001). MDD patients showed lower glucose metabolism of 18F-FDG in Cingulate Gyrus (BA24), Superior Frontal Gyrus (BA6), Rectal Gyrus (BA11) and Orbital Gyrus (BA11/47) compared with the healthy control group. The severity of depression, salivary cortisol and sAA correlated negatively with regional glucose metabolism in Cingulate Gyrus (BA 24), Superior Frontal Gyrus (BA 6), Rectal Gyrus (BA 11) and Orbital Gyrus (BA 11/47). The combination of salivary cortisol, sAA, superior frontal gyrus and rectal gyrus was the potential predictor of depression for MDD patients (ΔR(2)=0.981, p<0.001). The present study showed that, MDD patients group showed higher salivary cortisol, sAA levels and lower glucose metabolism of (18)F-FDG in several brain areas compared with the healthy control group. The combination of salivary cortisol, sAA, glucose metabolism of (18)F-FDG of superior frontal gyrus and rectal gyrus may serve as a simple clinical tool for the early diagnosis of MDD.

[Therapeutic study of autologous Schwann cells' bridge graft into the brain of hemiparkinsonian monkey].

OBJECTIVE: To evaluate the therapeutic effect of autologous transplantation of Schwann cells as "bridge" between the medial forebrain bundle (MFB) and caudate nucleus, into the brain of hemiparkinsonian monkey. METHODS: Six monkeys were used following 6-OHDA-induced hemiparkinsonism. Three of them were autologous transplanted using Schwann cells as "bridges" between MFB and caudate nucleus. The Schwann cells were pre-treated using Hoechst33342. The other three monkeys received sham operation as controls. All the monkeys received behavioral assessment. The metabolism of dopamine was measured by SPECT using (99)Tcm-TRODAT-1 and PET using 18F-FP-beta-CIT. After a 4-month follow-up, the monkeys' brain were removed from the skull, fixed in 4% paraformaldehyde and cut into serial sections. A fluorescence microscope examination and a tyroxine hydroxylase (TH) immunohistochemistry study were made on the sections. Cell types were determined by double staining. The level of TH protein around the needle track was determined by Western blotting. RESULTS: All three monkeys, which had undergone Schwann cells autologous bridge graft showed a decrease in the disability score and two of them had an increase in motor activity. The apomorphine evoked rotation was also decreased. The symptoms of the monkeys, which received sham operation, had not amelioration. In SPECT examination, the radioactivity count was greatly increased in the grafted monkeys. The dopamine levels were significantly increased in the caudate nucleus from 61% (before graft) to 79% (after graft) while there's no change in control group. In histological examination, autologous Schwann cells could survive and migrate in the brain. Around the Schwann cells "bridge", there were numerous TH positive short fibers in the MFB area. Around the whole length of the "bridge", there were a lot of TH positive reactive astrocytes, especially in thalamus. TH protein around the needle track of the graft group was 243% compared with that of control group. CONCLUSION: Autologous Schwann cells bridge graft is a feasible technique with therapeutic effects on parkinson disease monkeys. The Schwann cells play an important role in dopaminergic axonal elongation and in inducing the TH positive phenotype of reactive astroglia cell around it.

[Study on glucose metabolic rate in non-small cell lung cancer patients with blood stasis syndrome and non-blood stasis syndrome].

OBJECTIVE: To study the difference of glucose metabolic rate in non-small cell lung cancer (NSCLC) patients with blood stasis syndrome and with non-blood stasis syndrome. METHODS: Whole body positron emission tomography (PET) and functional agent 2-[fluorine-18] fluorine-2-deoxy-glucose (18FDG) were used to detect the 18FDG uptake value in regions of interest (ROI) in tumor tissue of patients. RESULTS: In patients with same pathologic type, the maximum and mean standardized uptake value (Max SUV and Mean SUV) were significantly higher in the blood stasis group than those in the non-blood stasis group (P < 0.01); it also showed the same in patients with NSCLC of phase I, II and III (P < 0.05), but the 18FDG uptake rate was obviously enhanced in patients of phase IV (P < 0.01). CONCLUSION: The glucose uptake in NSCLC patients of blood stasis syndrome was higher than that in those with of non-blood stasis syndrome.

AFP-producing hepatoid adenocarcinoma of appendix: a case report of 18F-FDG PET/CT.

Hepatoid adenocarcinoma (HAC) is a rare tumor. We described here a rare case of appendix HAC. A 59-year-old man underwent F-18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for gradually elevated alpha-Fetoprotein level. Multiple masses in the abdominal cavity with moderate FDG uptake were revealed, suggesting malignant tumor with peritoneal metastasis. The patient underwent radical resection, and the postoperative pathological result was HAC originated from the appendix. To our knowledge, it is the first report of HAC of the appendix. Our study suggests that FDG PET/CT may help in detecting the primary tumor and the metastases of HAC.

Metabolic imaging of deep brain stimulation in anorexia nervosa: a 18F-FDG PET/CT study.

OBJECTIVES: Anorexia nervosa (AN), a disorder of unknown etiology, has the highest mortality rate of any psychiatric disorder. Drawing the brain metabolic pattern of AN may help to target the core biological and psychological features of the disorder and to perfect the diagnosis and recovery criteria. In this study, we used 18F-FDG PET to show brain metabolic network for AN. METHODS: Glucose metabolism in 6 AN patients and 12 age-matched healthy controls was studied using 18F-FDG PET. SPM2 was used to compare brain metabolism in AN patients with that in healthy controls. Four of 6 AN patients took deep brain stimulation (DBS) targeted in nucleus accumbens (NAcc). About 3 to 6 months after the surgery, the 4 AN patients took another 18F-FDG PET scan to assess the change in brain glucose metabolism. RESULTS: The SPM (statistical parametric mapping ) analysis showed hypermetabolism in the frontal lobe (bilateral, BA10, BA11, BA47), the limbic lobe (bilateral, hippocampus, and amygdala), lentiform nucleus (bilateral), left insula (BA13), and left subcallosal gyrus (BA25). It also showed hypometabolism in the parietal lobe (bilateral, BA7, BA40). The hypermetabolism in frontal lobe, hippocampus, and lentiform nucleus decreased after NAcc-DBS. CONCLUSIONS: The changes in brain glucose metabolism illustrated the brain metabolic pattern in AN patients. Furthermore, the pattern can be modulated by NAcc-DBS, which confirmed specificity of the pattern. The regions with altered metabolism could interconnect to form a network and integrate information related to appetite. Our study may provide information for targeting the potential candidate brain regions for understanding the pathophysiology of AN and assessing the effects of existing and future treatment approaches.

Efficacy of conventional whole-body ¹8F-FDG PET/CT in the incidental findings of parotid masses.

OBJECTIVE: The objective of this study was to evaluate the incidence of incidental parotid masses with conventional whole-body ¹8F-deoxyglucose (FDG) PET/CT and assess the ability of PET/CT to characterize these unexpected parotid lesions. METHODS: Fifty eight incidental findings of parotid masses with routine FDG PET/CT whole-body scan were reviewed in this retrospective analysis, which were selected from the patients without any known or suspected parotid disease in our PET center, from June 2005 to May 2009. 51 cases were operated or underwent a biopsy after a short-term PET/CT study; the remaining 7 cases had a follow-up. Parotid mass that showed both noncontrast CT (irregular shape and blurry border) and PET malignant features (high FDG uptake, SUV(max) > 3.0) was considered as positive for malignancy. Correlation of FDG PET/CT with histology or follow-up outcome was performed. RESULTS: Fifty eight unexpected findings of parotid masses accounted for 0.3% of the total cases in 4 years, including 11 (19.0%) malignant tumors and 47 (81.0%) benign lesions. 13 lesions manifested single nodule with malignant CT features and intense FDG activity, of which 6 were proved to be malignant; thus, sensitivity and positive predictive values were 54.5% (6 of 11) and 46.2% (6 of 13), respectively. 45 lesions showed either single nodule with benign CT features, or a low FDG uptake (SUV(max) ≤ 3.0), of which 40 were true negatives; therefore, specificity and negative predictive values were 85.1% (40 of 47) and 88.9% (40 of 45), respectively. All parotid masses except 9 benign and 1 malignant showed a high FDG uptake. Compared with SUV only, combined interpretation of PET and CT results displayed a lower sensitivity (90.9-54.5%), but a higher specificity (19.1-85.1%) and a higher overall accuracy. CONCLUSIONS: Whole-body FDG-PET/CT at the time of surveying the entire body condition is helpful for detecting the asymptomatic parotid masses. Combined noncontrast CT is an essential evidence for improving the diagnostic accuracy of FDG-PET/CT for parotid masses.