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Differential Equations     Hybrid Journal   (Followers: 2, SJR: 0.364, h-index: 15)
Differential Equations and Dynamical Systems     Hybrid Journal   (Followers: 1, SJR: 0.63, h-index: 7)
Digestive Diseases and Sciences     Hybrid Journal   (Followers: 5, SJR: 1.19, h-index: 89)
Directieve therapie     Hybrid Journal  
Discrete & Computational Geometry     Hybrid Journal   (Followers: 2, SJR: 1.269, h-index: 40)
Discrete Event Dynamic Systems     Hybrid Journal   (Followers: 2, SJR: 0.42, h-index: 32)
Distributed and Parallel Databases     Hybrid Journal   (Followers: 4, SJR: 0.766, h-index: 30)
Distributed Computing     Hybrid Journal   (Followers: 2, SJR: 1.41, h-index: 31)
DNP - Der Neurologe und Psychiater     Full-text available via subscription  
Documenta Ophthalmologica     Hybrid Journal   (Followers: 2, SJR: 0.946, h-index: 40)
Doklady Biochemistry and Biophysics     Hybrid Journal   (Followers: 2, SJR: 0.2, h-index: 10)
Doklady Biological Sciences     Hybrid Journal   (SJR: 0.248, h-index: 10)
Doklady Botanical Sciences     Hybrid Journal  
Doklady Chemistry     Hybrid Journal   (SJR: 0.272, h-index: 12)
Doklady Earth Sciences     Hybrid Journal   (SJR: 0.48, h-index: 17)
Doklady Mathematics     Hybrid Journal   (SJR: 0.345, h-index: 13)
Doklady Physical Chemistry     Hybrid Journal   (SJR: 0.299, h-index: 12)
Doklady Physics     Hybrid Journal   (Followers: 1, SJR: 0.293, h-index: 17)
Douleur et Analg├ęsie     Hybrid Journal   (SJR: 0.113, h-index: 6)
Drug Delivery and Translational Research     Hybrid Journal   (Followers: 2, SJR: 0.607, h-index: 8)
Drug Safety - Case Reports     Open Access  
Drugs : Real World Outcomes     Hybrid Journal   (Followers: 1)
Dynamic Games and Applications     Hybrid Journal   (Followers: 2, SJR: 0.481, h-index: 5)
Dysphagia     Hybrid Journal   (Followers: 89, SJR: 0.822, h-index: 52)
e & i Elektrotechnik und Informationstechnik     Hybrid Journal   (Followers: 9, SJR: 0.279, h-index: 9)
e-Neuroforum     Hybrid Journal  
Early Childhood Education J.     Hybrid Journal   (Followers: 14, SJR: 0.466, h-index: 16)
Earth Science Informatics     Hybrid Journal   (Followers: 3, SJR: 0.282, h-index: 7)
Earth, Moon, and Planets     Hybrid Journal   (Followers: 7, SJR: 0.303, h-index: 29)
Earthquake Engineering and Engineering Vibration     Hybrid Journal   (Followers: 7, SJR: 0.482, h-index: 21)
Earthquake Science     Hybrid Journal   (Followers: 8, SJR: 0.418, h-index: 9)
East Asia     Hybrid Journal   (Followers: 7, SJR: 0.18, h-index: 9)
Eating and Weight Disorders - Studies on Anorexia, Bulimia and Obesity     Hybrid Journal   (Followers: 9, SJR: 0.362, h-index: 27)
EcoHealth     Hybrid Journal   (Followers: 3, SJR: 0.88, h-index: 26)
Ecological Research     Hybrid Journal   (Followers: 8, SJR: 0.847, h-index: 43)
Economia e Politica Industriale     Hybrid Journal  
Economia Politica     Hybrid Journal   (SJR: 0.375, h-index: 6)
Economic Botany     Hybrid Journal   (Followers: 8, SJR: 0.527, h-index: 44)
Economic Bulletin     Hybrid Journal   (Followers: 4)
Economic Change and Restructuring     Hybrid Journal   (Followers: 1, SJR: 0.264, h-index: 9)
Economic Theory     Hybrid Journal   (Followers: 9, SJR: 2.557, h-index: 34)
Economic Theory Bulletin     Hybrid Journal   (Followers: 2)
Economics of Governance     Hybrid Journal   (Followers: 2, SJR: 0.408, h-index: 14)
Ecosystems     Hybrid Journal   (Followers: 19, SJR: 1.909, h-index: 93)
Ecotoxicology     Hybrid Journal   (Followers: 9, SJR: 1.333, h-index: 56)
Education and Information Technologies     Hybrid Journal   (Followers: 92, SJR: 0.366, h-index: 16)
Educational Assessment, Evaluation and Accountability     Hybrid Journal   (Followers: 19, SJR: 0.374, h-index: 15)
Educational Psychology Review     Hybrid Journal   (Followers: 17, SJR: 2.776, h-index: 61)
Educational Research for Policy and Practice     Hybrid Journal   (Followers: 8, SJR: 0.273, h-index: 9)
Educational Studies in Mathematics     Hybrid Journal   (Followers: 11, SJR: 0.825, h-index: 32)
Educational Technology Research and Development     Partially Free   (Followers: 80, SJR: 1.785, h-index: 52)
Electrical Engineering     Hybrid Journal   (Followers: 15, SJR: 0.336, h-index: 18)
Electrocatalysis     Hybrid Journal   (SJR: 0.883, h-index: 10)
Electronic Commerce Research     Hybrid Journal   (Followers: 3, SJR: 0.582, h-index: 16)
Electronic Markets     Hybrid Journal   (Followers: 5, SJR: 0.411, h-index: 8)
Electronic Materials Letters     Hybrid Journal   (Followers: 3, SJR: 1.407, h-index: 15)
Elemente der Mathematik     Hybrid Journal   (Followers: 1)
Emergency Radiology     Hybrid Journal   (Followers: 4, SJR: 0.678, h-index: 25)
Emission Control Science and Technology     Hybrid Journal   (Followers: 1)
Empirica     Hybrid Journal   (Followers: 3, SJR: 0.319, h-index: 16)
Empirical Economics     Hybrid Journal   (Followers: 8, SJR: 0.489, h-index: 31)
Empirical Software Engineering     Hybrid Journal   (Followers: 7, SJR: 1.285, h-index: 39)
Employee Responsibilities and Rights J.     Hybrid Journal   (Followers: 3, SJR: 0.361, h-index: 15)
Endocrine     Hybrid Journal   (Followers: 7, SJR: 0.878, h-index: 57)
Endocrine Pathology     Hybrid Journal   (Followers: 2, SJR: 0.638, h-index: 31)
Energy Efficiency     Hybrid Journal   (Followers: 12, SJR: 0.732, h-index: 14)
Energy Systems     Hybrid Journal   (Followers: 11, SJR: 1.176, h-index: 7)
Engineering With Computers     Hybrid Journal   (Followers: 5, SJR: 0.433, h-index: 30)
Entomological Review     Hybrid Journal   (Followers: 3, SJR: 0.144, h-index: 5)
Environment Systems & Decisions     Hybrid Journal   (Followers: 2)
Environment, Development and Sustainability     Hybrid Journal   (Followers: 29, SJR: 0.419, h-index: 29)
Environmental and Ecological Statistics     Hybrid Journal   (Followers: 5, SJR: 0.458, h-index: 32)
Environmental and Resource Economics     Hybrid Journal   (Followers: 17, SJR: 1.632, h-index: 54)
Environmental Biology of Fishes     Hybrid Journal   (Followers: 5, SJR: 0.725, h-index: 58)
Environmental Chemistry Letters     Hybrid Journal   (Followers: 2, SJR: 0.741, h-index: 28)
Environmental Earth Sciences     Hybrid Journal   (Followers: 12, SJR: 0.724, h-index: 63)
Environmental Economics and Policy Studies     Hybrid Journal   (Followers: 5, SJR: 0.524, h-index: 4)
Environmental Evidence     Open Access   (Followers: 1)
Environmental Fluid Mechanics     Hybrid Journal   (Followers: 2, SJR: 0.437, h-index: 24)
Environmental Geochemistry and Health     Hybrid Journal   (Followers: 3, SJR: 1.013, h-index: 36)
Environmental Geology     Hybrid Journal   (Followers: 11)
Environmental Health and Preventive Medicine     Hybrid Journal   (Followers: 3, SJR: 0.522, h-index: 19)
Environmental Management     Hybrid Journal   (Followers: 32, SJR: 0.942, h-index: 66)
Environmental Modeling & Assessment     Hybrid Journal   (Followers: 10, SJR: 0.533, h-index: 31)
Environmental Monitoring and Assessment     Hybrid Journal   (Followers: 9, SJR: 0.685, h-index: 52)
Environmental Science and Pollution Research     Hybrid Journal   (Followers: 15, SJR: 0.885, h-index: 46)
Epileptic Disorders     Hybrid Journal   (SJR: 0.608, h-index: 38)
EPJ A - Hadrons and Nuclei     Hybrid Journal   (Followers: 1, SJR: 1.287, h-index: 63)
EPJ B - Condensed Matter and Complex Systems     Hybrid Journal   (Followers: 2, SJR: 0.731, h-index: 89)
EPJ direct     Hybrid Journal  
EPJ E - Soft Matter and Biological Physics     Hybrid Journal   (Followers: 1, SJR: 0.641, h-index: 62)
EPMA J.     Open Access   (SJR: 0.284, h-index: 6)
ERA-Forum     Hybrid Journal   (Followers: 3, SJR: 0.128, h-index: 3)
Erkenntnis     Hybrid Journal   (Followers: 13, SJR: 0.621, h-index: 16)
Erwerbs-Obstbau     Hybrid Journal   (SJR: 0.206, h-index: 9)
Esophagus     Hybrid Journal   (SJR: 0.311, h-index: 10)
Estuaries and Coasts     Hybrid Journal   (Followers: 7, SJR: 1.332, h-index: 67)
Ethical Theory and Moral Practice     Hybrid Journal   (Followers: 10, SJR: 0.297, h-index: 10)
Ethics and Information Technology     Hybrid Journal   (Followers: 79, SJR: 0.484, h-index: 23)
Ethik in der Medizin     Hybrid Journal   (SJR: 0.163, h-index: 6)

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Journal Cover   European Journal of Nuclear Medicine and Molecular Imaging
  [SJR: 2.056]   [H-I: 118]   [8 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1619-7089 - ISSN (Online) 1619-7070
   Published by Springer-Verlag Homepage  [2281 journals]
  • Very high coronary artery calcium score with normal myocardial perfusion
           SPECT imaging is associated with a moderate incidence of severe coronary
           artery disease
    • Abstract: Purpose Myocardial perfusion imaging (MPI) has limitations in the presence of balanced multivessel disease (MVD) and left main (LM) coronary artery disease, occasionally resulting in false-normal results despite the high cardiovascular risk associated with this condition. The purpose of this study was to assess the incidence of severe coronary artery disease (CAD) in the presence of a very high Agatston coronary artery calcium (CAC) score (>1,000) in stable symptomatic patients without known CAD but with normal MPI results. Methods A total of 2,659 prospectively acquired consecutive patients were referred for MPI and evaluation of CAC score by CT. Of this patient population, 8 % (222/2,659) had ischemia without myocardial infarction (MI) on MPIand 11 % (298/2,659) had abnormal MPI (MI and/or ischemia). On presentation 1 % of the patients (26/2,659) were symptomatic, had a CAC score >1,000 and normal MPI results. The definition of normal MPI was strict and included a normal hemodynamic response without ischemic ECG changes and normal imaging, particularly absence of transient ischemic dilation. All of these 26 patients with a CAC score >1,000 and normal MPI findings underwent cardiac catheterization. Results Of these 26 patients, 58 % (15/26) had severe disease (≥70 % stenosis) leading to revascularization. Of this group, 47 % (7/15) underwent percutaneous intervention, and 53 % (8/15) underwent coronary artery bypass grafting. All of these 15 patients had either MVD (14/15) or LM coronary artery disease (1/15), and represented 0.6 % (15/2,659) of all referred patients (95 % CI 0.3 – 0.9 %). The majority, 90 % (8/9), had severe CAD with typical chest pain. Conclusion A very high CAC score (>1,000) with normal MPI in a small subset of symptomatically stable patients was associated with a moderate incidence of severe CAD (95 % CI 37 – 77 %). Larger studies and/or a meta-analysis of small studies are needed to more precisely estimate the incidence of CAD in this population. This study also supports the concept that a normal MPI result in patients with severe CAD may be due to balanced MVD.
      PubDate: 2015-09-01
       
  • Frank Rösch: Nuclear and Radiochemistry, Volume 1: Introduction
    • PubDate: 2015-09-01
       
  • First evidence of PSMA expression in differentiated thyroid cancer using [
           68 Ga]PSMA-HBED-CC PET/CT
    • PubDate: 2015-09-01
       
  • Rhinal hypometabolism on FDG PET in healthy APO-E4 carriers: impact on
           memory function and metabolic networks
    • Abstract: Purpose The ε4 allele of the apolipoprotein E (APO-E4) gene, a genetic risk factor for Alzheimer’s disease (AD), also modulates brain metabolism and function in healthy subjects. The aim of the present study was to explore cerebral metabolism using FDG PET in healthy APO-E4 carriers by comparing cognitively normal APO-E4 carriers to noncarriers and to assess if patterns of metabolism are correlated with performance on cognitive tasks. Moreover, metabolic connectivity patterns were established in order to assess if the organization of neural networks is influenced by genetic factors. Methods Whole-brain PET statistical analysis was performed at voxel-level using SPM8 with a threshold of p < 0.005, corrected for volume, with age, gender and level of education as nuisance variables. Significant hypometabolism between APO-E4 carriers (n = 11) and noncarriers (n = 30) was first determined. Mean metabolic values with clinical/neuropsychological data were extracted at the individual level, and correlations were searched using Spearman’s rank test in the whole group. To evaluate metabolic connectivity from metabolic cluster(s) previously identified in the intergroup comparison, voxel-wise interregional correlation analysis (IRCA) was performed between groups of subjects. Results APO-E4 carriers had reduced metabolism within the left anterior medial temporal lobe (MTL), where neuropathological changes first appear in AD, including the entorhinal and perirhinal cortices. A correlation between metabolism in this area and performance on the DMS48 (delayed matching to sample-48 items) was found, in line with converging evidence involving the perirhinal cortex in object-based memory. Finally, a voxel-wise IRCA revealed stronger metabolic connectivity of the MTL cluster with neocortical frontoparietal regions in carriers than in noncarriers, suggesting compensatory metabolic networks. Conclusion Exploring cerebral metabolism using FDG PET can contribute to a better understanding of the influence of genetic factors on cerebral metabolism at both the local and network levels leading to phenotypical variations of the healthy brain and selective vulnerability.
      PubDate: 2015-09-01
       
  • The impact of obesity on the relationship between epicardial adipose
           tissue, left ventricular mass and coronary microvascular function
    • Abstract: Purpose Epicardial adipose tissue (EAT) has been linked to coronary artery disease (CAD) and coronary microvascular dysfunction. However, its injurious effect may also impact the underlying myocardium. This study aimed to determine the impact of obesity on the quantitative relationship between left ventricular mass (LVM), EAT and coronary microvascular function. Methods A total of 208 (94 men, 45 %) patients evaluated for CAD but free of coronary obstructions underwent quantitative [15O]H2O hybrid positron emission tomography (PET)/CT imaging. Coronary microvascular resistance (CMVR) was calculated as the ratio of mean arterial pressure to hyperaemic myocardial blood flow. Results Obese patients [body mass index (BMI) > 25, n = 133, 64 % of total] had more EAT (125.3 ± 47.6 vs 93.5 ± 42.1 cc, p < 0.001), a higher LVM (130.1 ± 30.4 vs 114.2 ± 29.3 g, p < 0.001) and an increased CMVR (26.6 ± 9.1 vs 22.3 ± 8.6 mmHg×ml−1×min−1×g−1, p < 0.01) as compared to nonobese patients. Male gender (β = 40.7, p < 0.001), BMI (β = 1.61, p < 0.001), smoking (β = 6.29, p = 0.03) and EAT volume (β = 0.10, p < 0.01) were identified as independent predictors of LVM. When grouped according to BMI status, EAT was only independently associated with LVM in nonobese patients. LVM, hypercholesterolaemia and coronary artery calcium score were independent predictors of CMVR. Conclusion EAT volume is associated with LVM independently of BMI and might therefore be a better predictor of cardiovascular risk than BMI. However, EAT volume was not related to coronary microvascular function after adjustments for LVM and traditional risk factors.
      PubDate: 2015-09-01
       
  • Focal impairment in myocardial fatty acid imaging in the left anterior
           descending artery area, a strong predictor for cardiac death in
           hemodialysis patients without obstructive coronary artery disease
    • Abstract: Purpose We investigated whether impaired patterns of myocardial fatty acid imaging were associated with cardiac death in dialysis patients without coronary lesions. Methods We prospectively enrolled 155 hemodialysis patients without obstructive coronary artery disease, who had been examined by single-photon emission computed tomography (SPECT) using the iodinated fatty acid analogue BMIPP. Uptake of BMIPP on SPECT was graded in 17 segments on a five-point scale (0, normal; 4, absent) and assessed as BMIPP summed scores. Of the enrolled 155 participants, we analyzed 95 who had BMIPP summed scores ≥ 6 (52 men and 43 women, 65 ± 11 years). BMIPP scores ≥ 2 in ≥ 2 consecutive segments in SPECT were defined as focal, and the others as non-focal pattern. Results Of 95 participants analyzed, 42 (44.2 %) showed focal and 53 (55.8 %) non-focal type. During follow-up for 5.1 ± 2.0 years, 42 died of cardiac events. The occurrence of cardiac death was higher in the focal than in the non-focal group (30/42 [71.4 %] versus 12/53 [22.6 %], p = 0.001). In stepwise Cox hazard analysis, focal pattern was associated with cardiac death (hazard ratio 2.266), independent of impairment of BMIPP SPECT (BMIPP summed scores ≥ 12). The predictive potential of BMIPP SPECT for cardiac death was higher (p < 0.001) in the left anterior descending artery area compared with other coronary territories. Conclusions Focal impairment in myocardial fatty acid imaging in the left anterior descending area may strongly predict cardiac death in this population.
      PubDate: 2015-09-01
       
  • Amyloid PET in European and North American cohorts; and exploring age as a
           limit to clinical use of amyloid imaging
    • Abstract: Purpose Several radiotracers that bind to fibrillar amyloid-beta in the brain have been developed and used in various patient cohorts. This study aimed to investigate the comparability of two amyloid positron emission tomography (PET) tracers as well as examine how age affects the discriminative properties of amyloid PET imaging. Methods Fifty-one healthy controls (HCs), 72 patients with mild cognitive impairment (MCI) and 90 patients with Alzheimer’s disease (AD) from a European cohort were scanned with [11C]Pittsburgh compound-B (PIB) and compared with an age-, sex- and disease severity-matched population of 51 HC, 72 MCI and 84 AD patients from a North American cohort who were scanned with [18F]Florbetapir. An additional North American population of 246 HC, 342 MCI and 138 AD patients with a Florbetapir scan was split by age (55–75 vs 76–93 y) into groups matched for gender and disease severity. PET template-based analyses were used to quantify regional tracer uptake. Results The mean regional uptake patterns were similar and strong correlations were found between the two tracers across the regions of interest in HC (ρ = 0.671, p = 0.02), amyloid-positive MCI (ρ = 0.902, p < 0.001) and AD patients (ρ = 0.853, p < 0.001). The application of the Florbetapir cut-off point resulted in a higher proportion of amyloid-positive HC and a lower proportion of amyloid-positive AD patients in the older group (28 and 30 %, respectively) than in the younger group (19 and 20 %, respectively). Conclusions These results illustrate the comparability of Florbetapir and PIB in unrelated but matched patient populations. The role of amyloid PET imaging becomes increasingly important with increasing age in the diagnostic assessment of clinically impaired patients.
      PubDate: 2015-09-01
       
  • Alterations of left ventricular deformation and cardiac sympathetic
           derangement in patients with systolic heart failure: a 3D speckle tracking
           echocardiography and cardiac 123 I-MIBG study
    • Abstract: Purpose Myocardial contractile function is under the control of cardiac sympathetic activity. Three-dimensional speckle tracking echocardiography (3D-STE) and cardiac imaging with 123I-metaiodobenzylguanidine (123I-MIBG) are two sophisticated techniques for the assessment of left ventricular (LV) deformation and sympathetic innervation, respectively, which offer important prognostic information in patients with heart failure (HF). The purpose of this investigation was to explore, in patients with systolic HF, the relationship between LV deformation assessed by 3D-STE and cardiac sympathetic derangement evaluated by 123I-MIBG imaging. Methods We prospectively studied 75 patients with systolic HF. All patients underwent a 3D-STE study (longitudinal, circumferential, area and radial) and 123I-MIBG planar and SPECT cardiac imaging. Results 3D-STE longitudinal, circumferential and area strain values were correlated with 123I-MIBG late heart to mediastinum (H/M) ratio and late SPECT total defect score. After stratification of the patients according to ischaemic or nonischaemic HF aetiology, we observed a good correlation of all 3D-STE measurements with late H/M ratio and SPECT data in the ischaemic group, but in patients with HF of nonischaemic aetiology, no correlation was found between LV deformation and cardiac sympathetic activity. At the regional level, the strongest correlation between LV deformation and adrenergic innervation was found for the left anterior descending coronary artery distribution territory for all four 3D-STE values. In multivariate linear regression analyses, including age, gender, LV ejection fraction, NYHA class, body mass index, heart rate and HF aetiology, only 3D-STE area and radial strain values significantly predicted cardiac sympathetic derangement on 123I-MIBG late SPECT. Conclusion This study indicated that 3D-STE measurements are correlated with 123I-MIBG planar and SPECT data. Furthermore, 3D-STE area and radial strain values, but not LVEF, predict cardiac sympathetic derangement in human postischaemic HF.
      PubDate: 2015-09-01
       
  • Validation of pixel-wise parametric mapping of myocardial blood flow with
           13 NH 3 PET in patients with hypertrophic cardiomyopathy
    • Abstract: Purpose Transmural abnormalities in myocardial blood flow (MBF) are important causes of ischaemia in patients with left ventricular (LV) hypertrophy. The study aimed to test whether pixel-wise parametric mapping of 13NH3 MBF can reveal transmural abnormalities in patients with hypertrophic cardiomyopathy (HCM). Methods We submitted 11 HCM patients and 9 age-matched controls with physiological LV hypertrophy to rest and stress (dipyridamole) 13NH3 PET. We measured MBF using a compartmental model, and obtained rest and stress parametric maps. Pixel MBF values were reorganized to obtain subendocardial and subepicardial MBF of LV segments. Results MBF at rest was higher in the subendocardial than in the subepicardial layer: 0.78 ± 0.19 vs. 0.60 ± 0.18 mL/min/g in HCM patients; 0.92 ± 0.24 vs. 0.75 ± 0.24 mL/min/g in controls (both p < 0.0001). Transmural perfusion gradient (TPG = subendocardial MBF/subepicardial MBF) at rest was similar: 1.35 ± 0.31 in HCM patients; 1.28 ± 0.27 in controls (NS). During stress, controls maintained higher subendocardial MBF: 2.44 ± 0.54 vs. 1.96 ± 0.67 mL/min/g tissue (p < 0.0001), with a TPG of 1.33 ± 0.35 (NS vs. rest). In HCM patients, the difference between subendocardial and subepicardial MBF was reduced (1.46 ± 0.48 vs. 1.36 ± 0.48 mL/min/g tissue, p < 0.01) and TPG decreased to 1.11 ± 0.34 (p < 0.0001 vs. rest and vs. controls). In HCM patients 8 of 176 segments had subendocardial MBF less than −2 × SD of the mean, versus none of 144 segments in controls (p < 0.01). Conclusion Pixel-wise parametric mapping of 13NH3 MBF enables the identification of transmural abnormalities in patients with HCM.
      PubDate: 2015-09-01
       
  • Metabolic patterns in prion diseases: an FDG PET voxel-based analysis
    • Abstract: Purpose Clinical diagnosis of human prion diseases can be challenging since symptoms are common to other disorders associated with rapidly progressive dementia. In this context, 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) might be a useful complementary tool. The aim of this study was to determine the metabolic pattern in human prion diseases, particularly sporadic Creutzfeldt-Jakob disease (sCJD), the new variant of Creutzfeldt-Jakob disease (vCJD) and fatal familial insomnia (FFI). Methods We retrospectively studied 17 patients with a definitive, probable or possible prion disease who underwent FDG PET in our institution. Of these patients, 12 were diagnosed as sCJD (9 definitive, 2 probable and 1 possible), 1 was diagnosed as definitive vCJD and 4 were diagnosed as definitive FFI. The hypometabolic pattern of each individual and comparisons across the groups of subjects (control subjects, sCJD and FFI) were evaluated using a voxel-based analysis. Results The sCJD group exhibited a pattern of hypometabolism that affected both subcortical (bilateral caudate, thalamus) and cortical (frontal cortex) structures, while the FFI group only presented a slight hypometabolism in the thalamus. Individual analysis demonstrated a considerable variability of metabolic patterns among patients, with the thalamus and basal ganglia the most frequently affected areas, combined in some cases with frontal and temporal hypometabolism. Conclusion Patients with a prion disease exhibit a characteristic pattern of brain metabolism presentation in FDG PET imaging. Consequently, in patients with rapidly progressive cognitive impairment, the detection of these patterns in the FDG PET study could orient the diagnosis to a prion disease.
      PubDate: 2015-09-01
       
  • Test–retest repeatability of myocardial blood flow and infarct size
           using 11 C-acetate micro-PET imaging in mice
    • Abstract: Purpose Global and regional responses of absolute myocardial blood flow index (iMBF) are used as surrogate markers to assess response to therapies in coronary artery disease. In this study, we assessed the test–retest repeatability of iMBF imaging, and the accuracy of infarct sizing in mice using 11C-acetate PET. Methods 11C-Acetate cardiac PET images were acquired in healthy controls, endothelial nitric oxide synthase (eNOS) knockout transgenic mice, and mice after myocardial infarction (MI) to estimate global and regional iMBF, and myocardial infarct size compared to 18F-FDG PET and ex-vivo histology results. Results Global test–retest iMBF values had good coefficients of repeatability (CR) in healthy mice, eNOS knockout mice and normally perfused regions in MI mice (CR = 1.6, 2.0 and 1.5 mL/min/g, respectively). Infarct size measured on 11C-acetate iMBF images was also repeatable (CR = 17 %) and showed a good correlation with the infarct sizes found on 18F-FDG PET and histopathology (r 2 > 0.77; p < 0.05). Conclusion 11C-Acetate micro-PET assessment of iMBF and infarct size is repeatable and suitable for serial investigation of coronary artery disease progression and therapy.
      PubDate: 2015-09-01
       
  • MR-based attenuation correction for cardiac FDG PET on a hybrid PET/MRI
           scanner: comparison with standard CT attenuation correction
    • Abstract: Purpose The aim of this study was to evaluate the feasibility of attenuation correction (AC) for cardiac 18F-labelled fluorodeoxyglucose (FDG) positron emission tomography (PET) using MR-based attenuation maps. Methods We included 23 patients with no known cardiac history undergoing whole-body FDG PET/CT imaging for oncological indications on a PET/CT scanner using time-of-flight (TOF) and subsequent whole-body PET/MR imaging on an investigational hybrid PET/MRI scanner. Data sets from PET/MRI (with and without TOF) were reconstructed using MR AC and semi-quantitative segmental (20-segment model) myocardial tracer uptake (per cent of maximum) and compared to PET/CT which was reconstructed using CT AC and served as standard of reference. Results Excellent correlations were found for regional uptake values between PET/CT and PET/MRI with TOF (n = 460 segments in 23 patients; r = 0.913; p < 0.0001) with narrow Bland-Altman limits of agreement (−8.5 to +12.6 %). Correlation coefficients were slightly lower between PET/CT and PET/MRI without TOF (n = 460 segments in 23 patients; r = 0.851; p < 0.0001) with broader Bland-Altman limits of agreement (−12.5 to +15.0 %). PET/MRI with and without TOF showed minimal underestimation of tracer uptake (−2.08 and −1.29 %, respectively), compared to PET/CT. Conclusion Relative myocardial FDG uptake obtained from MR-based attenuation corrected FDG PET is highly comparable to standard CT-based attenuation corrected FDG PET, suggesting interchangeability of both AC techniques.
      PubDate: 2015-09-01
       
  • A Cochrane review on brain [ 18 F]FDG PET in dementia: limitations and
           future perspectives
    • PubDate: 2015-09-01
       
  • Left atrial enlargement increases the risk of major adverse cardiac events
           independent of coronary vasodilator capacity
    • Abstract: Purpose Longstanding uncontrolled atherogenic risk factors may contribute to left atrial (LA) hypertension, LA enlargement (LAE) and coronary vascular dysfunction. Together they may better identify risk of major adverse cardiac events (MACE). The aim of this study was to test the hypothesis that chronic LA hypertension as assessed by LAE modifies the relationship between coronary vascular function and MACE. Methods In 508 unselected subjects with a normal clinical 82Rb PET/CT, ejection fraction ≥40 %, no prior coronary artery disease, valve disease or atrial fibrillation, LAE was determined based on LA volumes estimated from the hybrid perfusion and CT transmission scan images and indexed to body surface area. Absolute myocardial blood flow and global coronary flow reserve (CFR) were calculated. Subjects were systematically followed-up for the primary end-point – MACE – a composite of all-cause death, myocardial infarction, hospitalization for heart failure, stroke, coronary artery disease progression or revascularization. Results During a median follow-up of 862 days, 65 of the subjects experienced a composite event. Compared with subjects with normal LA size, subjects with LAE showed significantly lower CFR (2.25 ± 0.83 vs. 1.95 ± 0.80, p = 0.01). LAE independently and incrementally predicted MACE even after accounting for clinical risk factors, medication use, stress left ventricular ejection fraction, stress left ventricular end-diastolic volume index and CFR (chi-squared statistic increased from 30.9 to 48.3; p = 0.001). Among subjects with normal CFR, those with LAE had significantly worse event-free survival (risk adjusted HR 5.4, 95 % CI 2.3 – 12.8, p < 0.0001). Conclusion LAE and reduced CFR are related but distinct cardiovascular adaptations to atherogenic risk factors. LAE is a risk marker for MACE independent of clinical factors and left ventricular volumes; individuals with LAE may be at risk of MACE despite normal coronary vascular function.
      PubDate: 2015-09-01
       
  • β-Amyloid binding in elderly subjects with declining or stable
           episodic memory function measured with PET and [ 11 C]AZD2184
    • Abstract: Purpose Cognitive decline has been suggested as an early marker for later onset of Alzheimer’s disease. We therefore explored the relationship between decline in episodic memory and β-amyloid using positron emission tomography (PET) and [11C]AZD2184, a radioligand with potential to detect low levels of amyloid deposits. Methods Healthy elderly subjects with declining (n = 10) or stable (n = 10) episodic memory over 15 years were recruited from the population-based Betula study and examined with PET. Brain radioactivity was measured after intravenous administration of [11C]AZD2184. The binding potential BP ND was calculated using linear graphical analysis with the cerebellum as reference region. Results The binding of [11C]AZD2184 in total grey matter was generally low in the declining group, whereas some binding could be observed in the stable group. Mean BP ND was significantly higher in the stable group compared to the declining group (p = 0.019). An observation was that the three subjects with the highest BP ND were ApoE ε4 allele carriers. Conclusions We conclude that cognitive decline in the general population does not seem to stand by itself as an early predictor for amyloid deposits.
      PubDate: 2015-09-01
       
  • Test–retest reproducibility of the metabotropic glutamate receptor 5
           ligand [ 18 F]FPEB with bolus plus constant infusion in humans
    • Abstract: Purpose [18F]FPEB is a promising PET radioligand for the metabotropic glutamate receptor 5 (mGluR5), a potential target for the treatment of neuropsychiatric diseases. The purpose of this study was to evaluate the test–retest reproducibility of [18F]FPEB in the human brain. Methods Seven healthy male subjects were scanned twice, 3 – 11 weeks apart. Dynamic data were acquired using bolus plus infusion of 162 ± 32 MBq [18F]FPEB. Four methods were used to estimate volume of distribution (V T): equilibrium analysis (EQ) using arterial (EQA) or venous input data (EQV), MA1, and a two-tissue compartment model (2 T). Binding potential (BP ND) was also estimated using cerebellar white matter (CWM) or gray matter (CGM) as the reference region using EQ, 2 T and MA1. Absolute test–retest variability (aTRV) of V T and BP ND were calculated for each method. Venous blood measurements (C V) were compared with arterial input (C A) to examine their usability in EQ analysis. Results Regional V T estimated by the four methods displayed a high degree of agreement (r 2 ranging from 0.83 to 0.99 among the methods), although EQA and EQV overestimated V T by a mean of 9 % and 7 %, respectively, compared to 2 T. Mean values of aTRV of V T were 11 % by EQA, 12 % by EQV, 14 % by MA1 and 14 % by 2 T. Regional BP ND also agreed well among the methods and mean aTRV of BP ND was 8 – 12 % (CWM) and 7 – 9 % (CGM). Venous and arterial blood concentrations of [18F]FPEB were well matched during equilibrium (C V = 1.01 · C A, r 2 = 0.95). Conclusion [18F]FPEB binding shows good TRV with minor differences among analysis methods. Venous blood can be used as an alternative for input function measurement instead of arterial blood in EQ analysis. Thus, [18F]FPEB is an excellent PET imaging tracer for mGluR5 in humans.
      PubDate: 2015-09-01
       
  • Dosimetry for 177 Lu-DKFZ-PSMA-617: a new radiopharmaceutical for the
           treatment of metastatic prostate cancer
    • Abstract: Purpose Dosimetry is critical to achieve the optimal therapeutic effect of radioligand therapy (RLT) with limited side effects. Our aim was to perform image-based absorbed dose calculation for the new PSMA ligand 177Lu-DKFZ-PSMA-617 in support of its use for the treatment of metastatic prostate cancer. Methods Whole-body planar images and SPECT/CT images of the abdomen were acquired in five patients (mean age 68 years) for during two treatment cycles at approximately 1, 24, 48 and 72 h after administration of 3.6 GBq (range 3.4 to 3.9 GBq) 177Lu-DKFZ-PSMA-617. Quantitative 3D SPECT OSEM reconstruction was performed with corrections for photon scatter, photon attenuation and detector blurring. A camera-specific calibration factor derived from phantom measurements was used for quantitation. Absorbed doses were calculated for various organs from the images using a combination of linear approximation, exponential fit, and target-specific S values, in accordance with the MIRD scheme. Absorbed doses to bone marrow were estimated from planar and SPECT images and with consideration of the blood sampling method according to the EANM guidelines. Results The average (± SD) absorbed doses per cycle were 2.2 ± 0.6 Gy for the kidneys (0.6 Gy/GBq), 5.1 ± 1.8 Gy for the salivary glands (1.4 Gy/GBq), 0.4 ± 0.2 Gy for the liver (0.1 Gy/GBq), 0.4 ± 0.1 Gy for the spleen (0.1 Gy/GBq), and 44 ± 19 mGy for the bone marrow (0.012 Gy/GBq). The organ absorbed doses did not differ significantly between cycles. The critical absorbed dose reported for the kidneys (23 Gy) was not reached in any patient. At 24 h there was increased uptake in the colon with 50 – 70 % overlap to the kidneys on planar images. Absorbed doses for tumour lesions ranged between 1.2 and 47.5 Gy (13.1 Gy/GBq) per cycle. Conclusion The salivary glands and kidneys showed high, but not critical, absorbed doses after RLT with 177Lu-DKFZ-PSMA-617. We suggest that 177Lu-DKFZ-PSMA-617 is suitable for radiotherapy, offering tumour-to-kidney ratios comparable to those with RLT agents currently available for the treatment of neuroendocrine tumours. Our dosimetry results suggest that 177Lu-DKFZ-PSMA-617 treatment with higher activities and more cycles is possible without the risk of damaging the kidneys.
      PubDate: 2015-08-29
       
  • Distinct spatiotemporal patterns for disease duration and stage in
           Parkinson’s disease
    • Abstract: Purpose To assess correlations between the degree of dopaminergic depletion measured using single-photon emission computed tomography (SPECT) and different clinical parameters of disease progression in Parkinson’s disease (PD). Methods This retrospective study included 970 consecutive patients undergoing 123I-ioflupane SPECT scans in our institution between 2003 and 2013, from which we selected a study population of 411 patients according to their clinical diagnosis: 301 patients with PD (69.4 ± 11.0 years, of age, 163 men) and 110 patients with nondegenerative conditions included as controls (72.7 ± 8.0 years of age, 55 men). Comprehensive and operator-independent data analysis included spatial normalization into standard space, estimation of the mean uptake values in the striatum (caudate nucleus + putamen) and voxel-wise correlation between SPECT signal intensity and disease stage as well as disease duration in order to investigate the spatiotemporal pattern of the dopaminergic nigrostriatal degeneration. To compensate for potential interactions between disease stage and disease duration, one parameter was used as nonexplanatory coregressor for the other. Results Increasing disease stage was associated with an exponential decrease in 123I-ioflupane uptake (R 2  = 0.1501) particularly in the head of the ipsilateral caudate nucleus (p < 0.0001), whereas increasing disease duration was associated with a linear decrease in 123I-ioflupane uptake (p < 0.0001; R 2  = 0.1532) particularly in the contralateral anterior putamen (p < 0.0001). Conclusion We observed two distinct spatiotemporal patterns of posterior to anterior dopaminergic depletion associated with disease stage and disease duration in patients with PD. The developed operator-independent reference database of 411 123I-ioflupane SPECT scans can be used for clinical and research applications.
      PubDate: 2015-08-29
       
  • Development and validation of a direct-comparison method for cardiac 123
           I-metaiodobenzylguanidine washout rates derived from late 3-hour and
           4-hour imaging
    • Abstract: Purpose The washout rate (WR) has been used in 123I-metaiodobenzylguanidine (MIBG) imaging to evaluate cardiac sympathetic innervation. However, WR varies depending on the time between the early and late MIBG scans. Late scans are performed at either 3 or 4 hours after injection of MIBG. The aim of this study was to directly compare the WR at 3 hours (WR3h) with the WR at 4 hours (WR4h). Methods We hypothesized that the cardiac count would reduce linearly between the 3-hour and 4-hour scans. A linear regression model for cardiac counts at two time-points was generated. We enrolled a total of 96 patients who underwent planar 123I-MIBG scintigraphy early (15 min) and during the late phase at both 3 and 4 hours. Patients were randomly divided into two groups: a model-creation group (group 1) and a clinical validation group (group 2). Cardiac counts at 15 minutes (countearly), 3 hours (count3h) and 4 hours (count4h) were measured. Cardiac count4h was mathematically estimated using the linear regression model from countearly and count3h. Results In group 1, the actual cardiac count4h/countearly was highly significantly correlated with count3h/countearly (r = 0.979). In group 2, the average estimated count4h was 92.8 ± 31.9, and there was no significant difference between this value and the actual count4h (91.9 ± 31.9). Bland-Altman analysis revealed a small bias of −0.9 with 95 % limits of agreement of −6.2 and +4.3. WR4h calculated using the estimated cardiac count4h was comparable to the actual WR4h (24.3 ± 9.6 % vs. 25.1 ± 9.7 %, p = ns). Bland-Altman analysis and the intraclass correlation coefficient showed that there was excellent agreement between the estimated and actual WR4h. Conclusion The linear regression model that we used accurately estimated cardiac count4h using countearly and count3h. Moreover, WR4h that was mathematically calculated using the estimated count4h was comparable to the actual WR4h.
      PubDate: 2015-08-23
       
  • Test–retest reproducibility of [ 11 C]PBR28 binding to TSPO in
           healthy control subjects
    • Abstract: Purpose The PET radioligand [11C]PBR28 binds to the translocator protein (TSPO), a marker of brain immune activation. We examined the reproducibility of [11C]PBR28 binding in healthy subjects with quantification on a regional and voxel-by-voxel basis. In addition, we performed a preliminary analysis of diurnal changes in TSPO availability. Methods Twelve subjects were examined using a high-resolution research tomograph and [11C]PBR28, six in the morning and afternoon of the same day, and six in the morning on two separate days. Regional volumes of distribution (V T) were derived using a region-of-interest based two-tissue compartmental analysis (2TCM), as well as a parametric approach. Metabolite-corrected arterial plasma was used as input function. Results For the whole sample, the mean absolute variability in V T in the grey matter (GM) was 18.3 ± 12.7 %. Intraclass correlation coefficients in GM regions ranged from 0.90 to 0.94. Reducing the time of analysis from 91 to 63 min yielded a variability of 16.9 ± 14.9 %. There was a strong correlation between the parametric and 2TCM-derived GM values (r = 0.99). A significant increase in GM V T was observed between the morning and afternoon examinations when using secondary methods of quantification (p = 0.028). In the subjects examined at the same time of the day, the absolute variability was 15.9 ± 12.2 % for the 91-min 2TCM data. Conclusion V T of [11C]PBR28 binding showed medium reproducibility and high reliability in GM regions. Our findings support the use of parametric approaches for determining [11C]PBR28 V T values, and indicate that the acquisition time could be shortened. Diurnal changes in TSPO binding in the brain may be a potential confounder in clinical studies and should be investigated further.
      PubDate: 2015-08-22
       
 
 
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