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Background: Dopamine transporter (DAT) imaging of striatum is clinically used in Parkinson's disease (PD) and neurodegenerative parkinsonian syndromes (PS) especially in the early disease stages. The aim of the present study was to evaluate the diagnostic performance of the recently developed tracer for DAT imaging [18F]FE-PE2I PET/CT to the reference standard [123I]FP-CIT SPECT. Methods: Ninety-eight unselected patients referred for DAT imaging were included prospectively and consecutively and evaluated with [18F]FE-PE2I PET/CT and [123I]FP-CIT SPECT on two separate days. PET and SPECT scans were categorized independently by two blinded expert readers as either normal, vascular changes, or mixed. Semiquantitative values were obtained for each modality and compared regarding effect size using Glass' delta. Results: Fifty-six of the [123I]FP-CIT SPECT scans were considered abnormal (52 caused by PS, 4 by infarctions). Using [18F]FE-PE2I PET/CT, 95 of the 98 patients were categorized identically to SPECT as PS or non-PS with a sensitivity of 0.94 [0.84–0.99] and a specificity of 1.00 [0.92–1.00]. Inter-reader agreement for [18F]FE-PE2I PET with a kappa of 0.97 [0.89–1.00] was comparable to the agreement for [123I]FP-CIT SPECT of 0.96 [0.76–1.00]. Semiquantitative values for short 10-min reconstructions of [18F]FE-PE2I PET/CT were comparable to longer reconstructions. The effect size for putamen/caudate nucleus ratio was significantly increased using PET compared to SPECT. Conclusions: The high correspondence of [18F]FE-PE2I PET compared to reference standard [123I]FP-CIT SPECT establishes [18F]FE-PE2I PET as a feasible PET tracer for clinical use with favourable scan logistics. [ABSTRACT FROM AUTHOR]

The diagnosis of Parkinson's disease is based on clinical features with pathological verification. However, autopsy has been found to confirm a specialist diagnosis in only about 75% of cases. Especially early in the course of the disease, the clinical diagnosis can be difficult. Imaging of presynaptic dopamine transporters (DAT receptors) has provided a possible diagnostic probe in the evaluation of Parkinson's disease. The cocaine analogue [[sup 123]I]-2-β-carboxymethoxy-3-β(4-iodophenyl)tropane ([[sup 123]I]-β-CIT) is one of several radioligands that have been developed for single-photon emission tomography (SPET). The purpose of this study was to evaluate the impact of [[sup 123]I]-β-CIT SPET on the diagnosis and clinical management of patients with a primary, tentative diagnosis of parkinsonism. We undertook a retrospective evaluation of the clinical records of 90 consecutive patients referred to [[sub 123]I]-β-CIT SPET from the neurological department, Bispebjerg Hospital. In 58 subjects the scans revealed altered tracer uptake consistent with Parkinson's disease, progressive supranuclear palsy and multiple system atrophy. A significant change in the management or treatment because of the scan was found in 25 patients (28%). The sensitivity of the examination was 97% and the specificity 83%. In conclusion, a significant clinical impact of DAT receptor SPET imaging was found. DAT receptor imaging is a useful diagnostic probe in patients with a possible diagnosis of parkinsonism. [ABSTRACT FROM AUTHOR]

Abstract. Correct staging is crucial for the management and prognosis of patients with malignant melanoma. The aim of this prospective study was to compare staging by whole-body positron emission tomography using fluorine-18 fluorodeoxyglucose ([sup 18]F-FDG) with staging by conventional methods. Thirty-eight patients with malignant melanoma of clinical stage II (local recurrence, intransit and regional lymph node metastases) or III (metastases to other sites than in stage II) were included in the study. The results of the PET scans were compared with those obtained by clinical examination, computed tomography, ultrasound, radiography, and liver function tests and histology or clinical follow-up. With [sup 18]F-FDG PET we found for all loci a sensitivity of 97% and a specificity of 56%, compared with 62% and 22%, respectively, when using routine methods. For intra-abdominal foci, the sensitivity and specificity were 100% for both [sup 18]F-FDG PET and routine methods. Corresponding figures for pulmonary/intrathoracic foci were 100% and 33%, respectively. Of the patients included in this study, 34% would not have been staged correctly by conventional methods alone. We conclude from this study that [sup 18]F-FDG PET is a sensitive method superior to conventional methods for detecting widespread metastases from malignant melanoma. Mutilating surgery of no benefit can thereby be avoided. [sup 18]F-FDG PET is useful as a supplement to... [ABSTRACT FROM AUTHOR]

Abstract: The low density of cerebellar dopamine D2/D3 receptors provides the basis for using the cerebellum as a representation of free- and non-specifically bound radioligand in positron emission tomography (PET) and single photon emission computed tomography (SPECT) studies. With the development of ultra high-affinity dopamine D2/D3 ligands like [123I]epidepride, [18F]fallypride, and [11C]FLB-457, quantification of extrastriatal low density receptor populations including the cerebellum is possible with important implications for calculation of binding parameters. [123I]epidepride-SPECT was performed in 23 patients with schizophrenia before and after 3 months of antipsychotic treatment with either risperidone (n =14) or zuclopenthixol (n =9). In the unblocked situation and partially blocked situation, the average distribution volumes were 5.2±1.3 mL/mL and 4.0±0.8 mL/mL, respectively. The paired distribution volumes were reduced by 22±15% (mean±SD) after antipsychotic treatment (p <0.0001, paired Student’s t-test). From the paired distribution volumes in cerebellum and extrastriatal regions, the average distribution volume representing free and non-specifically bound [123I]epidepride was calculated to be 3.3±0.8 mL/mL. Both the % [123I]epidepride fraction of plasma radioactivity (p >0.76) and the plasma [123I]epidepride concentration (p >0.45) were unchanged after antipsychotic treatment (paired Student’s t-test). These results strongly suggest the presence of “non-negligible” specific [123I]epidepride binding to dopamine D2/D3 receptors in the cerebellum. Using the cerebellum as a representation of free and non-specifically bound radioligand and neglecting the specifically bound component may lead to results that erroneously imply that antipsychotic drugs bind to extrastriatal dopamine D2/D3 receptors with a higher affinity than to striatal dopamine D2/D3 receptors. [Copyright &y& Elsevier]

Background: The aim of the study was to examine extrastriatal dopamine D2/3 receptor binding and psychopathology in schizophrenic patients, and to relate binding potential (BP) values to psychopathology. Methods: Twenty-five drug-naive schizophrenic patients and 20 healthy controls were examined with single-photon emission computerized tomography (SPECT) using the D2/3-receptor ligand [123I]epidepride. Results: In the hitherto largest study on extrastriatal D2/3 receptors we detected a significant correlation between frontal D2/3 BP values and positive schizophrenic symptoms in the larger group of male schizophrenic patients, higher frontal BP values in male (n = 17) compared to female (n = 8) patients, and – in accordance with this – significantly fewer positive schizophrenic symptoms in the female patients. No significant differences in BP values were observed between patients and controls; the patients, however, had significantly higher BP in the right compared to the left thalamus, whereas no significant hemispheric imbalances were observed in the healthy subjects. Conclusions: The present data are the first to confirm a significant correlation between frontal D2/3 receptor BP values and positive symptoms in male schizophrenic patients. They are in agreement with the hypothesis that frontal D2/3 receptor activity is significant for positive psychotic symptoms. Additionally, the data support a thalamic hemispheric imbalance in schizophrenia. [Copyright &y& Elsevier]

Abstract: EEG feedback methods, which link the occurrence of alpha to the presentation of repeated visual stimuli, reduce the relative variability of subsequent, alpha-blocking event durations. The temporal association between electro-cortical field activation and regional cerebral blood flow (rCBF) led us to investigate whether the reduced variability of alpha-blocking durations with feedback is associated with a reduction in rCBF variability. Reduced variability in the rCBF response domain under EEG feedback control might have methodological implications for future brain-imaging studies. Visual stimuli were randomly presented to seven subjects, contingent upon the occurrence of alpha (alpha-contingent stimulation (ACS)) or alpha-blocking (not-alpha-blocking-contingent stimulation (NACS)) events. We employed a within-subjects design. rCBF was measured from multiple, cortical and sub-cortical regions. The primary dependent variables were the Mean, Standard Deviation and the ratio of Mean/Standard Deviation of: 1) the alpha-blocking response durations and 2) the temporally summated rCBF responses within the Visual Associative regions of interest (ROIs). Additional within-subjects rCBF measures were derived to quantify the variance-reducing effects of ACS across multiple, distributed areas of the brain. Both EEG and rCBF measures demonstrated decreased variability under ACS. This improved control was seen for localized as well as anatomically distributed rCBF measures. [Copyright &y& Elsevier]