[Clinical magnetic resonance imaging : Frequent incidental cerebral findings]. / Klinische Magnetresonanztomographie : Häufige zerebrale Zufallsbefunde.

The increasing use of magnetic resonance imaging (MRI) in clinical diagnostics means that patients and physicians are confronted more often with incidental findings. In the literature there are fluctuating data on the incidence of such findings and guidelines concerning the further procedure exist in only very few cases, such as incidental aneurysms and pituitary adenomas. The diagnostic and therapeutic implications which can be derived from incidental findings depend on multiple factors, such as anatomical location, patient age, comorbidity and patient wishes. For this reason it often makes sense to refer patients with incidental findings to an interdisciplinary neurological center at an early stage. In this review frequent incidental cerebral findings, epidemiological data, imaging criteria and, where possible, recommendations for the further procedure are shown.

Advocating neuroimaging studies of transmitter release in human physical exercise challenges studies.

This perspective attempts to outline the emerging role of positron emission tomography (PET) ligand activation studies in human exercise research. By focusing on the endorphinergic system and its acclaimed role for exercise-induced antinociception and mood enhancement, we like to emphasize the unique potential of ligand PET applied to human athletes for uncovering the neurochemistry of exercise-induced psychophysiological phenomena. Compared with conventional approaches, in particular quantification of plasma beta-endorphin levels under exercise challenges, which are reviewed in this article, studying opioidergic effects directly in the central nervous system (CNS) with PET and relating opioidergic binding changes to neuropsychological assessments, provides a more refined and promising experimental strategy. Although a vast literature dating back to the 1980s of the last century has been able to reproducibly demonstrate peripheral increases of beta-endorphin levels after various exercise challenges, so far, these studies have failed to establish robust links between peripheral beta-endorphin levels and centrally mediated behavioral effects, ie, modulation of mood and/or pain perception. As the quantitative relation between endorphins in the peripheral blood and the CNS remains unknown, the question arises, to what extent conventional blood-based methods can inform researchers about central neurotransmitter effects. As previous studies using receptor blocking approaches have also revealed equivocal results regarding exercise effects on pain and mood processing, it is expected that PET and other functional neuroimaging applications in athletes may in future help uncover some of the hitherto unknown links between neurotransmission and psychophysiological effects related to physical exercise.