Evaluation of novel 3D-printed and conventional thermoplastic stereotactic high-precision patient fixation masks for radiotherapy.

Purpose: For stereotactic radiation therapy of intracranial malignancies, a patient's head needs to be immobilized with high accuracy. Fixation devices such as invasive stereotactic head frames or non-invasive thermoplastic mask systems are often used. However, especially stereotactic high-precision masks often cause discomfort for patients due to a long manufacturing time during which the patient is required to lie still and because the face is covered, including the mouth, nose, eyes, and ears.

Neurobiological processes during the Cambridge gambling task.

Although vast research has been conducted concerning gambling behavior this is the first study combining behavioral and functional magnetic resonance imaging (fMRI) data while using the Cambridge Gambling Task (CGT). We tested 20 healthy right-handed men and chose an event-related design to allow for precise temporal separation of gambling stages. In the color decision stage participants had to guess whether a yellow token was hidden behind red or blue boxes presented in varying color ratios, then stake wagers during the bet decision stage.

An fMRI study of training voluntary smooth circular eye movements.

Despite a large number of recent studies, the promise of fMRI methods to produce valuable insights into motor skill learning has been restricted to sequence learning paradigms, or manual training paradigms where a relatively advanced capacity for sensory-motor integration and effector coordination already exists. We therefore obtained fMRIs from 16 healthy adults trained in a new paradigm that demanded voluntary smooth circular eye movements without a moving target. This aimed to monitor neural activation during two possible motor learning processes: (a) the smooth pursuit control system develops a new perceptual-motor relationship and successfully becomes involved in voluntary action in which it is not normally involved or (b) the saccadic system normally used for voluntary eye movement and which only exhibits linear action skill develops new dynamic coordinative control capable of smooth circular movement.

Interactive knowledge discovery with the doctor-in-the-loop: a practical example of cerebral aneurysms research.

Established process models for knowledge discovery find the domain-expert in a customer-like and supervising role. In the field of biomedical research, it is necessary to move the domain-experts into the center of this process with far-reaching consequences for both their research output and the process itself. In this paper, we revise the established process models for knowledge discovery and propose a new process model for domain-expert-driven interactive knowledge discovery.

MRI assessment of relapsed glioblastoma during treatment with bevacizumab: volumetric measurement of enhanced and FLAIR lesions for evaluation of response and progression--a pilot study.

Purpose: To develop a magnetic resonance imaging (MRI) metric that is useful for therapy monitoring in patients with relapsed glioblastoma (GBM) during treatment with the antiangiogenic monoclonal antibody bevacizumab (Bev). We evaluated the feasibility of tumour volume measurement with our software tool in clinical routine and tried to establish reproducible and quantitative parameters for surveillance of patients on treatment with antiangiogenic drugs.

Materials And Methods: In this retrospective institutional pilot study, 18 patients (11 men, 7 women; mean age 53.

Involvement of area MT in bimanual finger movements in left-handers: an fMRI study.

The ease with which humans are able to perform symmetric movements of both hands has traditionally been attributed to the preference of the motor system to activate homologous muscles. Recently, we have shown in right-handers, however, that bimanual index finger adduction and abduction movements in incongruous hand orientations (one palm down/other up) preferentially engaged parietal perception-associated brain areas. Here, we used functional magnetic resonance imaging to investigate the influence of hand orientation in left-handers on cerebral activation during bimanual index finger movements.

Cerebrovascular biomodeling for aneurysm surgery: simulation-based training by means of rapid prototyping technologies.

Objective: Opportunities for developing procedural skills are progressively rare. Therefore, sophisticated educational tools are highly warranted.

Methods: This study compared stereolithography and 3-dimensional printing for simulating cerebral aneurysm surgery.

Assessment of gadolinium leakage into traumatic spinal cord lesion using magnet resonance imaging.

Study Design: Exploratory study in patients with acute spinal cord trauma using magnetic resonance imaging (MRI).

Objective: The aim of this study was to assess the leakage of Gd-DTPA into traumatic lesions of the human spinal cord using MRI.

Summary Of Background Data: While MRI of acute spinal cord trauma is a routine type of clinical investigation, the time course of Gd-DTPA enhancement in traumatic spinal cord injury is not known.

Effect of repetitive arm cycling following botulinum toxin injection for poststroke spasticity: evidence from FMRI.

Background And Objective: Investigations were performed to establish if repetitive arm cycling training enhances the antispastic effect of intramuscular botulinum toxin (BTX) injections in postischemic spastic hemiparesis. Effects on cerebral activation were evaluated by functional magnetic resonance imaging (fMRI).

Methods: Eight chronic spastic hemisyndrome patients (49 ± 10 years) after middle cerebral artery infarction (5.

Data-driven analyses of an fMRI study of a subject experiencing phosphenes.

Purpose: To compare two data-driven methods of statistical image analysis, principal and independent component analysis (PCA, ICA), in identifying neural networks related to the transient occurrence of phosphenes experienced by a female patient subsequent to a brain infarct.

Materials And Methods: An initial functional magnetic resonance imaging (fMRI) session consisted of two acquisitions: one of the patient experiencing phosphenes and a second responding to a well-defined visual stimulation paradigm. A second fMRI session 6 months later, when the patient no longer experienced phosphenes, consisted of an acquisition in which no stimulation was presented.

I know where you'll look: an fMRI study of oculomotor intention and a change of motor plan.

Background: Electrophysiological studies in monkeys showed that the intention to perform a saccade and the covert change in motor plan are reflected in the neural activity of the posterior parietal cortex (PPC).

Methods: To investigate whether such covert intentional processes are demonstrable in humans as well we used event related functional MRI. Subjects were instructed to fixate a central target, which changed its color in order to indicate the direction of a subsequent saccade.

Perceptual influence on bimanual coordination: an fMRI study.

In bimanual coordination subjects typically show a spontaneous preference for movement symmetry. While there is experimental evidence for the principle of muscle homology, recent evidence suggested that bimanual coordination may be mediated as perceptual goals (Mechsner et al., 2001).

Impact of fMRI-guided advanced DTI fiber tracking techniques on their clinical applications in patients with brain tumors.

Introduction: White matter tractography based on diffusion tensor imaging has become a well-accepted non-invasive tool for exploring the white matter architecture of the human brain in vivo. There exist two main key obstacles for reconstructing white matter fibers: firstly, the implementation and application of a suitable tracking algorithm, which is capable of reconstructing anatomically complex fascicular pathways correctly, as, e.g.

Brain activity for peripheral biological motion in the posterior superior temporal gyrus and the fusiform gyrus: Dependence on visual hemifield and view orientation.

Biological motion, the movement of the human body presented by a small number of point lights, activates among other regions lining the posterior superior temporal sulcus (pSTS) and gyrus (pSTG) and of the fusiform gyrus. In previous studies with foveal stimuli the activity in the pSTS/pSTG was often confined to the right hemisphere and bilateral in fusiform gyrus. We presented biological motion stimuli in peripheral vision and measured the BOLD responses with functional MRI to test whether the right dominance in pSTS/pSTG also occurred with peripheral stimuli.

Brain activation in response to bladder filling and simultaneous stimulation of the dorsal clitoral nerve--an fMRI study in healthy women.

Aims: Using functional magnetic resonance imaging (fMRI) we investigated the cortical and subcortical representations during bladder filling and the effect of simultaneous stimulation of the dorsal clitoral nerve on these cortical and subcortical structures.

Methods: After approval of the local ethics committee, 8 healthy females were included. Prior to scanning, subjects were catheterized and the bladder was filled until first desire to void occurred.

Cortical and subcortical correlates of functional electrical stimulation of wrist extensor and flexor muscles revealed by fMRI.

The main scope of this study was to test the feasibility and reliability of FES in a MR-environment. Functional Electrical Stimulation (FES) is used in the rehabilitation therapy of patients after stroke or spinal cord injury to improve their motor abilities. Its principle lies in applying repeated electrical stimulation to the relevant nerves or muscles for eliciting either isometric or concentric contractions of the treated muscles.

Interaction of visual hemifield and body view in biological motion perception.

The brain network for the recognition of biological motion includes visual areas and structures of the mirror-neuron system. The latter respond during action execution as well as during action recognition. As motor and somatosensory areas predominantly represent the contralateral side of the body and visual areas predominantly process stimuli from the contralateral hemifield, we were interested in interactions between visual hemifield and action recognition.

Handedness and functional MRI-activation patterns in sentence processing.

We investigate differences of cerebral activation in 12 right-handed and left-handed participants, respectively, using a sentence-processing task. Functional MRI shows activation of left-frontal and inferior-parietal speech areas (BA 44, BA9, BA 40) in both groups, but a stronger bilateral activation in left-handers. Direct group comparison reveals a stronger activation in right-frontal cortex (BA 47, BA 6) and left cerebellum in left-handers.

Post-lesional cerebral reorganisation: evidence from functional neuroimaging and transcranial magnetic stimulation.

Reorganisation of cerebral representations has been hypothesised to underlie the recovery from ischaemic brain infarction. The mechanisms can be investigated non-invasively in the human brain using functional neuroimaging and transcranial magnetic stimulation (TMS). Functional neuroimaging showed that reorganisation is a dynamic process beginning after stroke manifestation.

A portable and low-cost fMRI compatible pneumatic system for the investigation of the somatosensensory system in clinical and research environments.

There still is a need for devices that allow reproducible stimulation of skin areas of the human body. We constructed a stimulation system and tested it by using brief pneumatic stimulation to the right thumb of nine healthy volunteers. BOLD-signals in response to tactile stimulation with frequencies of 1, 3 and 5 Hz were measured using a 3T MRI scanner.

An fMRI study of optokinetic nystagmus and smooth-pursuit eye movements in humans.

Both optokinetic nystagmus (OKN) and smooth-pursuit eye movements (SPEM) are subclasses of so-called slow eye movements. However, optokinetic responses are reflexive whereas smooth pursuit requires the voluntary tracking of a moving target. We used functional magnetic resonance imaging (fMRI) to determine the neural basis of OKN and SPEM, and to uncover whether the two underlying neural systems overlap or are independent at the cortical level.

Bimanual recoupling by visual cueing in callosal disconnection.

The cerebral control of bimanual movements is not completely understood. We investigated a 59-year-old, right-handed man who presented with an acute bimanual coordination deficit. Magnetic resonance imaging showed a lesion involving the entire corpus callosum, which was found on stereotactic biopsy to be an ischemic infarct.

Reorganisation of cerebral circuits in human ischemic brain disease.

Animal experiments suggest that reorganisation of cerebral representations is the neurobiological basis of post-lesional recovery. In human ischemic brain disease recovery is a dynamic and sustained process beginning after stroke manifestation. The mechanisms underlying recovery can be investigated non-invasively in the human brain using functional neuroimaging and transcranial magnetic stimulation (TMS).

The encoding of saccadic eye movements within human posterior parietal cortex.

Over the last few years, several functionally distinct subregions of the posterior parietal cortex (PPC) have been shown to subserve oculomotor control. Since these areas seem to overlap with regions whose activation is related to attention, we used functional magnetic resonance imaging to compare the cerebral activation pattern evoked by eye movements with different attentional loads, i.e.