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  • 1
    Electronic Resource
    Electronic Resource
    (68Ga)-EDTA positron emission tomography in the diagnosis of brain tumors (1984)
    Springer
    Neuroradiology 26 (1984), S. 393-398 
    Details
    ISSN: 1432-1920
    Keywords: 68Ga scintigraphy ; positron emission tomography ; brain tumors ; tumor tracer uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fifty-two patients with active brain tumors and 8 patients with brain lesions from surgical treatment and/or radio-and/or chemotherapy of their brain tumors were examined by positron emission tomography (PET) using (68Ga)-EDTA in addition to conventional X-ray computed tomography (XCT). All patients with active brain tumors showed abnormal uptake of radioactivity in the tumor region, while all treated patients had normal PET scans. Site and shape of abnormal radioactivity accumulation were in good agreement with the tumor as demonstrated by XCT. Small tumors had a tendency to appear larger in PET than in XCT, while tumors with a mean largest diameter of more than 50.7 mm in XCT usually appeared smaller in PET. Despite considerable overlap to tumor classes with respect to their degree of tracer uptake a highly significant decreasing order of tumor-sagittal sinus ratios of radioactivity (TSR) was found, malignant gliomas ranking highest (median TSR 0.634), followed by meningiomas (median TSR 0.522) and metastases (median TSR 0.391), benign gliomas showing the least uptake (median TSR 0.307). These findings suggest that PET with (68Ga)-EDTA has a high sensitivity supplementing XCT in the diagnosis of brain tumors, and may be helpful in early detection of recurrent tumor growth after therapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327493
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  • 2
    Electronic Resource
    Electronic Resource
    Diaschisis of specific cerebellar lobules: pontine haematoma studied with high-resolution PET and MRI (1996)
    Springer
    Journal of neurology 243 (1996), S. 131-136 
    Details
    ISSN: 1432-1459
    Keywords: Positron emission tomography ; Cerebellar diaschisis ; Pontine haematoma ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cerebellar glucose metabolism was studied in one patient with a hemipontine haematoma in order to investigate remote metabolic effects within the cerebellar lobules. In the patient, who suffered a circumscribed hemipontine haemorrhage, and in three normal subjects cerebellar glucose metabolisms was studied using18F-2-fluoro-2-deoxy-d-glucose and high-resolution positron emission tomography (PET). Regions of interest were placed on sagittal brain slices of co-registered magnetic resonance images for quantitative evaluation of glucose metabolism in each cerebellar lobule. Interruption of corticopontine fibres caused inactivation of pontine nuclei with subsequent contralateral cerebellar diaschisis, mainly in the anterior lobe and the posterior portion of the quadrangular lobule. Damage within the ponto-cerebellar part of the cortico-ponto-cerebellar pathway, e.g. pontine nuclei and crossing ponto-cerebellar fibres from contralateral pontine nuclei, led to ipsi- and contralateral cerebellar diaschisis within the semilunar, gracile and biventral lobules. High-resolution PET is capable of demonstrating bilateral diaschisis involving specific cerebellar lobules to a different degree that is consistent with the pontine anatomy of the cortico-ponto-cerebellar pathway and with the location of the haemorrhagic lesion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02444003
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  • 3
    Electronic Resource
    Electronic Resource
    Positron emission tomography with (18F)methylspiperone demonstrates D2 dopamine receptor binding differences of clozapine and haloperidol (1991)
    Springer
    Journal of neural transmission 86 (1991), S. 163-173 
    Details
    ISSN: 1435-1463
    Keywords: Positron emission tomography ; (18F)methylspiperone ; clozapine ; haloperidol ; D2 dopamine receptors ; schizophrenia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Four schizophrenic patients were investigated with dynamic positron emission tomography (PET) using (18F)fluorodeoxyglucose (FDG) and (18F)methylspiperone (MSP) as tracers. Two schizophrenics were on haloperidol therapy at the time of MSP PET. The other two schizophrenics were treated with clozapine, in one of them MSP PET was carried out twice with different daily doses (100 mg and 450 mg respectively). Neuroleptic serum levels were measured in all patients. Results were compared with MSP PET of two drug-free male control subjects and with a previous fluoroethylspiperone (FESP) study of normals. Three hours after tracer injection specific binding of MSP was observed in the striatum in all cases. The striatum to cerebellum ratio was used to estimate the degree of neuroleptic-caused striatal D2 dopamine receptor occupancy. In the haloperidol treated patients MSP binding was significantly decreased, whereas in the clozapine treated patients striatum to cerebellum ratio was normal. Even the increase of clozapine dose in the same patient had no influence on this ratio. Despite the smaller number of patients the study shows for the first time in humans that striatal MSP binding reflects the different D2 dopamine receptor affinities of clozapine and haloperidol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01250702
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  • 4
    Electronic Resource
    Electronic Resource
    Positron emission tomography in degenerative disorders of the dopaminergic system (1992)
    Springer
    Journal of neural transmission 4 (1992), S. 121-130 
    Details
    ISSN: 1435-1463
    Keywords: Dopaminergic system ; glucose metabolism ; positron emission tomography ; Parkinson's disease ; Alzheimer's disease ; progressive supranuclear palsy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 21 patients who had Parkinson's disease (PD), PD plus dementia of Alzheimer type (PDAT) or progressive supranuclear palsy (PSP), were studied with positron emission tomography (PET) using (18F)-2-fluoro-2-deoxy-D-glucose (FDG). In one patient with strictly unilateral PD side differences in striatal dopa uptake were studied with 6-(18F)fluoro-L-dopa (F-dopa). In patients with PD PET with FDG did not show any significant change in regional cerebral metabolic rates for glucose (rCMR(Glu)). In PDAT glucose metabolism was generally reduced, the most severe decrease was found in parietal cortex. The metabolic pattern was similar to that typically found in patients with Alzheimer's disease (AD). In the patient with strictly unilateral PD rCMR(Glu) was normal, F-dopa PET, however, revealed a distinct reduction of dopa uptake in the contralateral putamen. In PSP glucose metabolism was significantly decreased in subcortical regions (caudatum, putamen and brainstem) and in frontal cortex. Thus PET demonstrated a clear difference of metabolic pattern between PDAT and PSP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02251475
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  • 5
    Electronic Resource
    Electronic Resource
    In-vivo measurements of regional acetylcholine esterase activity in degenerative dementia: comparison with blood flow and glucose metabolism (2000)
    Springer
    Journal of neural transmission 107 (2000), S. 1457-1468 
    Details
    ISSN: 1435-1463
    Keywords: Keywords: Dementia ; cholinergic system ; acetylcholine esterase ; positron emission tomography ; cerebral blood flow ; cerebral glucose metabolism.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary. Memory and attention are cognitive functions that depend heavily on the cholinergic system. Local activity of acetylcholine esterase (AChE) is an indicator of its integrity. Using a recently developed tracer for positron emission tomography (PET), C-11-labeled N-methyl-4-piperidyl-acetate (C-11-MP4A), we measured regional AChE activity in 4 non-demented subjects, 4 patients with dementia of Alzheimer type (DAT) and 1 patient with senile dementia of Lewy body type (SDLT), and compared the findings with measurements of blood flow (CBF) and glucose metabolism (CMRGlc). Initial tracer extraction was closely related to CBF. AChE activity was reduced significantly in all brain regions in demented subjects, whereas reduction of CMRGlc and CBF was more limited to temporo-parietal association areas. AChE activity in SDLT was in the lower range of values in DAT. Our results indicate that, compared to non-demented controls, there is a global reduction of cortical AChE activity in dementia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s007020070009
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  • 6
    Electronic Resource
    Electronic Resource
    PET studies of dopamine receptor distribution using [18F]fluoroethylspiperone: findings in disorders related to the dopaminergic system (1990)
    Springer
    Journal of neural transmission 81 (1990), S. 195-213 
    Details
    ISSN: 1435-1463
    Keywords: Dopamine receptors ; positron emission tomography ; [18F]fluoroethylspiperone ; disorders of dopaminergic system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary PET studies of dopamine D2-receptor binding were performed in thirty patients with various disorders related to the dopaminergic system and in six healthy controls. Uptake of [18F]fluoroethylspiperone in caudate over three hours was analyzed in terms of several indices of receptor binding: caudateto-cerebellum activity ratio, concentration of ligand as percentage of injected dose, caudate-to-blood radioactivity ratio, slope of tracer uptake curves, binding potential, kinetic constants of a three compartment model. In 14 patients brain glucose metabolism was also measured. Data on medicated patients demonstrate that the average values of most of the above parameters indicate the decreased number of available D2-receptors whereby, besides an age dependent decline, the caudate-to-cerebellum ratio affords the relatively best distinction among diagnostic groups. In individual cases, large variability among subjects permits only the classification of severe pathologies. Morphological damage and neuronal loss in the striatum may also cause abnormal low values both for the indices of receptor binding and for glucose consumption, thus providing a possible pathogenetic link between receptor dysfunction and impaired energy metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01245042
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of tissue heterogeneity on quantification in positron emission tomography (1995)
    Springer
    European journal of nuclear medicine 22 (1995), S. 652-663 
    Details
    ISSN: 1619-7089
    Keywords: Positron emission tomography ; Tissue heterogeneity ; Tracer kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract As a result of the limited spatial resolution of positron emission tomographic scanners, the measurements of physiological parameters are compromised by tissue heterogeneity. The effect of tissue heterogeneity on a number of parameters was studied by simulation and an analytical method. Five common tracer models were assessed. The input and tissue response functions were assumed to be free from noise and systematic errors. The kinetic model was assumed to be perfect. Two components with different kinetics were mixed in different proportions and contrast with respect to the model parameters. Different experimental protocols were investigated. Of three methods investigated for the measurement of cerebral blood flow (CBF) (steady state, dynamic, integral), the second one was least sensitive to errors caused by tissue heterogeneity and the main effect was an underestimation of the distribution volume. With the steady state method, errors in oxygen extraction fraction caused by tissue heterogeneity were always found to be less than the corresponding errors in CBF. For myocardial blood flow the steady state method was found to perform better than the bolus method. The net accumulation of substrate (i.e. rCMRgjc in the case of glucose analogs) was found to be comparatively insensitive to tissue heterogeneity. Individual rate constants such ask 2 andk 3 for efflux and metabolism of the substrate in the pool of unmetabolized substrate in the tissue, respectively, were found to be more sensitive. In studies of radioligand binding, using only tracer doses, the effect of tissue heterogeneity on the parameterk on ·B max could be considerable. In studies of radioligand binding using a protocol with two experiments, one with high and one with low specific activity,B max was found to be insensitive whileK d was very sensitive to tissue heterogeneity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01254567
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