Publications by authors named "Armin De Greiff"

Introduction: This article is part of the Focus Theme of Methods of Information in Medicine on the German Medical Informatics Initiative. "Smart Medical Information Technology for Healthcare (SMITH)" is one of four consortia funded by the German Medical Informatics Initiative (MI-I) to create an alliance of universities, university hospitals, research institutions and IT companies. SMITH's goals are to establish Data Integration Centers (DICs) at each SMITH partner hospital and to implement use cases which demonstrate the usefulness of the approach.

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Rationale And Objectives: The purpose of this study was to perform high-resolution contrast-enhanced peripheral multistation magnetic resonance angiography using a new blood-pool contrast agent (gadofosveset trisodium; Vasovist) while suppressing venous signal by using an acquisition scheme with k-space segmentation.

Materials And Methods: Multistation peripheral magnetic resonance angiography with Vasovist was performed in 20 patients with known peripheral arterial occlusive disease. The k-space of the three-dimensional data sets was segmented such that the central parts were acquired during the first pass of the blood-pool agent, while the peripheral parts were acquired in the steady state.

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Cerebral activation patterns during the first three auto-suggestive phases of autogenic training (AT) were investigated in relation to perceived experiences. Nineteen volunteers trained in AT and 19 controls were studied with fMRI during the first steps of autogenic training. FMRI revealed activation of the left postcentral areas during AT in those with experience in AT, which also correlated with the level of AT experience.

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The relevance of the sensory system in the pathophysiology of cervical dystonia (CD) has been discussed since the description of sensory tricks associated with this disorder. Our objective was to locate changes in somatosensory processing of patients with CD responding in a passive sensory task of body regions that are not affected by dystonic symptoms. We used functional magnetic resonance imaging (fMRI) in 17 patients with CD and 17 healthy controls performing a strictly passive 30-degree forearm movement task with the left arm.

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Background: There is evidence that patients with anorexia nervosa (AN) demonstrate specific cerebral activation patterns in response to visual food stimulation. We postulated that cerebral activation patterns could represent different perceptions of high-calorie images during hunger and satiety and could be determined by patients' subjective ratings.

Methods: After 6 h of starvation and also in a state of satiety, 12 female patients with AN and 12 normal-weight women were assessed by use of fMRI with high-calorie food images.

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Objectives: The combination of parallel acquisition (generalized autocalibrating partially parallel acquisitions) and time-resolved three-dimensional (3D) view-sharing techniques is a promising tool for dynamic contrast-enhanced 3D-magnetic resonance angiography (MRA). We evaluated the influence of different k-space acquisition strategies on image quality for a recently developed time-resolved echo-shared angiographic technique during a contrast-enhanced 3D-MRA of the thoracic vessels.

Materials And Methods: In 20 patients (16 men, 4 women; range, 28-75 years), 2 dynamic MRA protocols with different k-space acquisition strategies were performed on a 1.

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Changes in neuronal activity have been described in patients with hemianopia following ischemic lesions of the visual cortex. This reorganization may facilitate compensation of lost visual function that is rarely fully restituted. Improving exploratory eye movements with appropriate training has been shown to partially compensate for the visuoperceptive impairment during daily life activities.

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Purpose: Recent functional magnetic resonance imaging (fMRI) studies have described reorganized activation of the oculomotor and visual cortex after focal brain lesions. These studies are based on comparison with healthy individuals who may have a very heterogenous refractive error. The influence of refractive error on the cortical control of an oculomotor task such as a prosaccade trial, however, is unknown.

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Objective: Previous fMRI studies on activation of working memory in multiple sclerosis (MS) patients presented heterogeneous results. Patients were reported to have altered brain activation patterns either in typical working memory circuits or in other brain regions even if they did not have any cognitive impairment according to the test batteries. We hypothesized that brain activation patterns in patients at a very early stage of the disease at very low EDSS-Score would not differ from healthy subjects.

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Objective: Low cardiorespiratory fitness (CRF) predisposes one to cardiovascular disease and type 2 diabetes in part independently of body weight. Given the close relationship between intrahepatic lipid content (IHL) and insulin sensitivity, we hypothesized that the direct relationship between fitness and insulin sensitivity may be explained by IHL.

Research Design And Methods: We included 138 overweight to obese, otherwise healthy subjects (aged 43.

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Objectives: Our study aimed to evaluate a three-dimensional (3D) threshold-based, region-growing segmentation algorithm for the assessment of left ventricular (LV) volumes in cardiac MRI.

Materials And Methods: Two-dimensional cine steady-state free precession short-axis scans (TR 3 milliseconds, TE 1.5 milliseconds, FA 60 degrees , section thickness 8 mm) covering the entire LV without slice gap were acquired in 44 consecutive patients on a 1.

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Temporal summation of nociceptive inputs in trigeminal networks can induce central sensitization and maintain chronic pain. We combined functional magnetic resonance imaging and electrically evoked pain-related potentials (PREP) in healthy human subjects to identify brain regions involved in temporal summation of nociceptive inputs. We stimulated the skin innervated by the ophthalmic division of the trigeminal nerve with trains of three, seven and eleven similar nociceptive pulses, while recording evoked hemodynamic or electrical brain responses.

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Recent functional MRI (fMRI) studies have described the increased task-related brain activation in older subjects during motor, cognitive and perceptual tasks. Age affects the ability to control saccadic eye movements. To investigate the age-related changes of oculomotor control, we studied the representation of saccades in 11 young (median age 29 years) and 11 older (median age 62 years) healthy individuals using fMRI.

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Substantial disability in patients with hemianopia results from reduced visual perception. Previous studies have shown that these patients have impaired saccades. Improving exploratory eye movements with appropriate training of saccades may help to partially compensate for the visuoperceptive impairment during daily life activities.

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Purpose: To assess the visibility of small myocardial lesions at magnetic resonance (MR) imaging and to estimate how much myocardial damage is necessary to enable detection of late gadolinium enhancement (LGE) in vivo.

Materials And Methods: The study was approved by the local bioethics committee. Coronary microembolization was performed by injecting 300,000 microspheres into the distal portion of the left anterior descending artery in 18 anesthetized minipigs to create multifocal areas of myocardial damage.

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Objective: The neurobiological mechanisms of deviant sexual preferences such as pedophilia are largely unknown. The objective of this study was to analyze whether brain activation patterns of homosexual pedophiles differed from those of a nonpedophile homosexual control group during visual sexual stimulation.

Method: A consecutive sample of 11 pedophile forensic inpatients exclusively attracted to boys and 12 age-matched homosexual control participants from a comparable socioeconomic stratum underwent functional magnetic resonance imaging during a visual sexual stimulation procedure that used sexually stimulating and emotionally neutral photographs.

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Changes in neuronal activity of the visual cortex have been described in patients with hemianopia. The anatomical areas that are involved in neuroplastic changes have not been studied in a larger group of stroke patients with a homogenous structural pathology of the visual cortex. Brain activation was measured in 13 patients with a single ischemic lesion of the striate cortex and partially recovered hemianopia and in 13 age-matched control subjects using blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI).

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Substantial disability in patients with hemianopia results from reduced visual perception. Several studies have shown that these patients have impaired saccades but may improve search strategies with appropriate training of saccades. We used fMRI to study the representation of saccades in patients with post-stroke hemianopia to the left.

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fMRI is one of the most likely applications to benefit from high field MRI. It profits from the higher signal-to-noise ratio (SNR) and increased BOLD contrast itself. However, this sensitivity to susceptibility brings with it problems, e.

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Idiopathic cervical dystonia (CD) and benign essential blepharospasm (BEB) are the most common forms of focal dystonia. Previous autopsy and imaging studies suggested that these disorders are not accompanied by structural brain abnormalities. However, recent brain voxel-based morphometry (VBM) studies of these conditions suggest that there actually may be changes in gray matter.

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Minipigs are widely used to examine physiologic mechanisms under experimental settings. The purpose of our study was to localize the visual cortex of minipigs using visual stimulation in functional magnetic resonance imaging (fMRI). Five male Göttinger minipigs were studied with fMRI during visual stimulation with series of light impulses conducted into the MR cabin via fibre optical wave guides (EPI sequences, block design, 1.

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Rationale: Partial neuromuscular transmission failure by acetylcholine receptor blockade (neuromuscular blockade) or antibody-mediated functional loss (myasthenia gravis), even with a magnitude of muscle weakness that does not evoke respiratory symptoms, can evoke dysphagia and decreased inspiratory airflow, and increases the risk of susceptible patients to develop severe pulmonary complications.

Objectives: To assess whether impaired neuromuscular transmission predisposes individuals to inspiratory upper airway collapse, we assessed supraglottic airway diameter and volume by respiratory-gated magnetic resonance imaging, upper airway dilator muscle function (genioglossus force and EMG), and changes in lung volume, respiratory timing, and peripheral muscle function before, during, and after partial neuromuscular blockade in healthy, awake volunteers.

Measurements And Main Results: Partial neuromuscular blockade (train-of-four [TOF] ratio: 0.

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Purpose: To demonstrate the feasibility of using a multiecho phase-contrast (PC) gradient-echo sequence with motion-sensitizing gradient (MSG) to accelerate MR elastography (MRE) acquisitions in comparison to single-echo PC sequences.

Materials And Methods: The sequence was implemented and compared with a conventional single-echo sequence as the standard of reference in both agarose phantoms and in vivo in the biceps of three healthy volunteers. For reconstruction of the elasticity modulus, a local frequency estimation (LFE) algorithm was used.

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Successful and unsuccessful intention to learn words was assessed by means of event-related functional MRI. Eighteen patients with schizophrenia and 15 healthy control participants were scanned while being given two word lists to read and another seven to learn with immediate recall. Neural activation patterns were segregated according to whether words were subsequently recalled or forgotten and these conditions were contrasted with each other and reading.

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Purpose: The aim of this study was to assess the regional relative interictal and postictal perfusion changes in temporal and parietal lobe epilepsy.

Methods: We investigated interictal and postictal magnet resonance perfusion changes in five patients with temporal lobe epilepsy either with hippocampal sclerosis (n = 3) or without (n = 2), and in one patient with extratemporal (parietal lobe) epilepsy. T(2)*-weighted single-shot echo-planar images were acquired after bolus application of 0.

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