Nuklearmedizinische Diagnostik bei Erkrankungen des zentralen Nervensystems
ABSTRACT Mit den nuklearmedizinischen Computertomographien PET und SPECT lassen sich zerebrale Perfusion, Glukoseverbrauch, Neurotransmission
und Aminosäureaufnahme untersuchen. Der vorliegende Artikel beschreibt den gegenwärtigen klinischen Stellenwert dieser Verfahren
in der Neuromedizin, die hinsichtlich einer Reihe von Indikationen konventioneller strukturgebender Bildgebung überlegen sind.
Positron-emission tomography (PET) and single photon emission computed tomography (SPECT) can be used to visualize and quantify
cerebral perfusion, glucose consumption, neurotransmission, and amino acid uptake. These techniques are clearly superior to
conventional structural imaging techniques for several indications. This contributioin describes the clinical role of PET
and SPECT in clinical neurology.
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ABSTRACT: Positron emission tomography (PET) with 18F-2-fluoro-2-deoxy-D-glucose (FDG) is widely applied to the study of gliomas. The histology of most gliomas is regionally heterogeneous. The relationship between histologic features and glucose metabolism evaluated by PET with FDG may therefore vary within the limits of the tumor. PET with FDG integrated in the planning of stereotactic brain biopsy allows precise comparison between local FDG uptake and histology. Using this approach, the authors investigated whether glucose metabolism of gliomas is related to anaplasia, and whether PET with FDG detects metabolic heterogeneity that parallels histologic heterogeneity of gliomas. A total of 161 biopsy samples collected from 20 PET-guided procedures performed in patients with gliomas (8 low grade astrocytomas, 8 anaplastic astrocytomas, 1 anaplastic oligoastrocytoma, and 3 glioblastomas) were analyzed for the presence or absence of 8 histologic features. Stereotactic coordinates were used to calculate the metabolic rate of glucose (MRGlu) in the region of each biopsy sample. Gray and white matter MRGlu were used to define four metabolic grades that were compared with local histology. The difference in MRGlu expressed as micromoles per 100 g per minute was highly significant between anaplastic and nonanaplastic samples; the median +/- quartile deviation was 23 +/- 16 in anaplastic samples and 18 +/- 5 in nonanaplastic samples (P < 0.005). Even more significant differences were found when MRGlu was normalized to the cortex or to the white matter. Metabolic grades were different in anaplastic and nonanaplastic samples (P < 0.0001). Approximately 75% of samples metabolically graded 3 or 4 demonstrated signs of anaplasia, compared with 10% of samples graded 0 or 1. FDG uptake in gliomas is anatomically heterogeneous and is regionally related to the presence of anaplasia.Cancer 09/1996; 78(5):1098-106. · 5.20 Impact Factor
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ABSTRACT: Variants of the apolipoprotein E allele appear to account for most cases of late-onset Alzheimer's disease, and persons with two copies of the epsilon 4 allele appear to have an especially high risk of dementia. Positron-emission tomography (PET) has identified specific regions of the brain in which the rate of glucose metabolism declines progressively in patients with probable Alzheimer's disease. We used PET to investigate whether these same regions of the brain are affected in subjects homozygous for the epsilon 4 allele before the onset of cognitive impairment. Apolipoprotein E genotypes were established in 235 volunteers 50 to 65 years of age who reported a family history of probable Alzheimer's disease. Neurologic and psychiatric evaluations, a battery of neuropsychological tests, magnetic resonance imaging, and PET were performed in 11 epsilon 4 homozygotes and 22 controls without the epsilon 4 allele who were matched for sex, age, and level of education. An automated method was used to generate an aggregate surface-projection map that compared regional rates of glucose metabolism in the two groups. The epsilon 4 homozygotes were cognitively normal. They had significantly reduced rates of glucose metabolism in the same posterior cingulate, parietal, temporal, and prefrontal regions as in previously studied patients with probable Alzheimer's disease. They also had reduced rates of glucose metabolism in additional prefrontal regions, which may be preferentially affected during normal aging. In late middle age, cognitively normal subjects who are homozygous for the epsilon 4 allele for apolipoprotein E have reduced glucose metabolism in the same regions of the brain as in patients with probable Alzheimer's disease. These findings provide preclinical evidence that the presence of the epsilon 4 allele is a risk factor for Alzheimer's disease. PET may offer a relatively rapid way of testing future treatments to prevent Alzheimer's disease.New England Journal of Medicine 01/1996; 334(12):752-758. · 51.66 Impact Factor
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ABSTRACT: The aim of the present study was to determine whether routine integration of positron emission tomography (PET) with 18F-labeled fluorodeoxyglucose (FDG) in the planning of stereotactic brain biopsy increases the technique's diagnostic yield. Forty-three patients underwent combined FDG-PET- and computerized tomography (CT)-guided stereotactic biopsy of intracranial lesions according to a previously described technique. In 36 patients, an area of abnormal FDG uptake was used to guide at least one stereotactic biopsy trajectory. A total of 90 stereotactic trajectories were performed; among them, 55 were based on FDG-PET-defined targets and 35 were based on CT-defined targets. Histological diagnosis was obtained in all patients, but six of the 90 trajectories were nondiagnostic; all six were based on targets defined by CT only. Differences between the diagnostic yield of trajectories based on FDG-PET-defined targets and those based on CT-defined targets were statistically significant in patients with contrast-enhanced lesions, but not in patients with nonenhancing lesions. These results support the view the FDG-PET may contribute to the successful management of brain tumor patients requiring stereotactic biopsy. Because no significant increase in discomfort or morbidity related to the technique was found, it is suggested that the development of similar techniques integrating PET data in the planning of stereotactic biopsy should be considered by centers performing stereotactic surgery and having access to PET technology.Journal of Neurosurgery 04/1995; 82(3):445-52. · 3.15 Impact Factor