Johannes T. Heverhagen

Learn More
STUDY OBJECTIVES Idiopathic rapid eye movement sleep behavior disorder (iRBD)--a parasomnia characterized by dream enactments--is a risk marker for the development of Parkinson disease (PD) and other alpha-synucleinopathies. The pathophysiology of iRBD is likely due to dysfunction of brainstem nuclei that regulate REM sleep. Diffusion tensor imaging (DTI)(More)
BACKGROUND Cluster headache (CH) is a rare headache disorder with severe unilateral headache bouts and autonomic symptoms. The pathophysiology of CH is not completely understood. Using a voxel-based morphometric paradigm or functional imaging, a key role of the hypothalamus and the pain matrix could be demonstrated during CH episodes. However, there are no(More)
PURPOSE To investigate the use of four-dimensional (4D) co-occurrence-based texture analysis to distinguish between nonmalignant and malignant tissues in dynamic contrast-enhanced (DCE) MR images. MATERIALS AND METHODS 4D texture analysis was performed on DCE-MRI data sets of breast lesions. A model-free neural network-based classification system assigned(More)
INTRODUCTION Adequate migration and differentiation of mesenchymal stem cells is essential for regeneration of large bone defects. To achieve this, modern graft materials are becoming increasingly important. Among them, electrospun nanofiber scaffolds are a promising approach, because of their high physical porosity and potential to mimic the extracellular(More)
One of the most powerful features of the dynamic contrast-enhanced (DCE) MRI technique is its capability to quantitatively measure the physiological or pathophysiological environments assessed by the passage of contrast agent by means of model-based pharmacokinetic analysis. The widely used two-compartment pharmacokinetic model developed by Brix and(More)
BACKGROUND Symptomatic narcolepsy is often related to hypothalamic, pontine, or mesencephalic lesions. Despite evidence of disturbances of the hypothalamic hypocretin system in patients with idiopathic narcolepsy, neuroimaging in patients with idiopathic narcolepsy revealed conflicting results and there is limited data on possible structural brain changes(More)
BACKGROUND AND PURPOSE the aim of this study was to investigate specific activation patterns and potential gender differences during mental rotation and to investigate whether functional magnetic resonance imaging (fMRI) and functional transcranial Doppler sonography (fTCD) lateralize hemispheric dominance concordantly. METHODS regional brain activation(More)
Theory of Mind (ToM) is the ability to infer other people's mental states like intentions or desires. ToM can be differentiated into affective (i.e., recognizing the feelings of another person) and cognitive (i.e., inferring the mental state of the counterpart) subcomponents. Recently, subcortical structures such as the basal ganglia (BG) have also been(More)
BACKGROUND AND PURPOSE MR sialography has become an alternative imaging technique for ductal salivary gland diseases. We compared the diagnostic accuracies of MR sialography and digital subtraction sialography in patients with successful completion of both examinations and benign salivary gland disorders. METHODS In a prospective study, we attempted to(More)
Using a T2* gradient echo magnetic resonance imaging (MRI) sequence, regional T2 signal intensity (SI) values, a surrogate marker for T2 values, were determined in 12 regions of interest (substantia nigra, pallidum, caudate head, thalamus, occipital white matter, and frontal white matter bilaterally) and in two reference regions (cerebrospinal fluid and(More)