MRI for attenuation correction in PET: methods and challenges.

In current combined PET/MR systems, PET attenuation correction is based on MRI, since the small bore inside MRI systems and the strong magnetic field do not permit a rotating PET transmission source or a CT device to be integrated. Unlike CT measurements in PET/CT scanners, the MR signal is not directly correlated to tissue density and thus cannot be converted by a simple transformation of intensity values. Various approaches have been developed based on templates, atlas information, direct segmentation of T1-weighted MR images, or segmentation of images from special MR sequences.

Studies of ⁶Li-NMR properties in different salt solutions in low magnetic fields.

In this article we report the longitudinal relaxation times (T(1)) of various (6)Li salts ((6)LiI, (6)LiCl and (6)LiNO(3)) in D(2)O and H(2)O, measured in low magnetic fields (B(0)=3.5mT). This investigation serves the purpose of clarifying the relaxation behavior of different (6)Li solutions and different concentrations.

Distributed intelligent sensor network for the rehabilitation of Parkinson's patients.

The coordination between locomotion and respiration of Parkinson's disease (PD) patients is reduced or even absent. The degree of this disturbance is assumed to be associated with the disease severity [S. Schiermeier, D.

Design and initial performance of PlanTIS: a high-resolution positron emission tomograph for plants.

Positron emitters such as (11)C, (13)N and (18)F and their labelled compounds are widely used in clinical diagnosis and animal studies, but can also be used to study metabolic and physiological functions in plants dynamically and in vivo. A very particular tracer molecule is (11)CO(2) since it can be applied to a leaf as a gas. We have developed a Plant Tomographic Imaging System (PlanTIS), a high-resolution PET scanner for plant studies.

iSANLA: intelligent sensor and actuator network for life science applications.

In the fields of neurological rehabilitation and neurophysiological research there is a strong need for miniaturized, multi channel, battery driven, wireless networking DAQ systems enabling real-time digital signal processing and feedback experiments. For the scientific investigation on the passive auditory based 3D-orientation of Barn Owls and the scientific research on vegetative locomotor coordination of Parkinson's disease patients during rehabilitation we developed our 'intelligent Sensor and Actuator Network for Life science Application' (iSANLA) system. Implemented on the ultra low power microcontroller MSP430 sample rates up to 96 kHz have been realised for single channel DAQ.

Online cardiac arrhythmia classification by means of circle maps analysis implemented on an intelligent miniaturized sensor.

The intermittent occurrence of cardiac arrhythmias like e.g. atrial fibrillation hampers their diagnosis and hence the treatment.

Automated topology correction for human brain segmentation.

We describe a new method to reconstruct human brain structures from 3D magnetic resonance brain images. Our method provides a fully automatic topology correction mechanism, thus avoiding tedious manual correction. Topological correctness is important because it is an essential prerequisite for brain atlas deformation and surface flattening.

From 2D PET to 3D PET: issues of data representation and image reconstruction.

Positron emission tomography (PET), intrinsically a 3D imaging technique, was for a long time exclusively operated in 2D mode, using septa to shield the detectors from photons emitted obliquely to the detector planes. However, the use of septa results in a considerable loss of sensitivity. From the late 1980s, significant efforts have been made to develop a methodology for the acquisition and reconstruction of 3D PET data.

Automatic parameter optimization for de-noising MR data.

This paper describes an automatic parameter optimization method for anisotropic diffusion filters used to de-noise 2D and 3D MR images. The filtering process is integrated into a closed-loop system where image improvement is monitored indirectly by comparing the characteristics of the suppressed noise with those of the assumed noise model at the optimal point. In order to verify the performance of this approach, experimental results obtained with this method are presented together with the results obtained by median and k-nearest neighbor filters.

Small animal PET: aspects of performance assessment.

Dedicated small animal positron emission tomography (PET) systems are increasingly prevalent in industry (e.g. for preclinical drug development) and biological research.

MRI-based individual 3D region-of-interest atlases of the human brain: a new method for analyzing functional data.

Objectives: Introduction of a new atlas-based method for analyzing functional data which takes into account the variability of individual human brains and the partial volume, effects of functional emission computed tomography, images in complex anatomical 3D regions, as well as, describing the underlying multi-modal image processing, principles.

Methods: 3D atlas extraction is done directly by automated segmentation of individual magnetic resonance images of the patient's head. This is done in two steps: voxel-based classification of T1-weighted images for tissue differentiation (low-level processing) is followed by knowledge-based analysis of the classified images for extraction of 3D anatomical regions (high-level processing).