Biomedical subjects

G Berks

Publications and source records attributed to G Berks.

5 recordsLinked to original sources

PubMed2001

Supra- and infrasylvian conduction aphasia.

Fifteen cases of conduction aphasia which were tested with the Aachen Aphasia Test (AAT), are presented. The CT lesion data were transformed to a standard 3D-reference brain referring to the ACPC line. According to the lesion profiles a group of 6 patients had pure suprasylvian lesions, a group of 4 patients had pure infrasylvian lesions, and a group of 5 patients had lesions in both supra- and infrasylvian regions. Suprasylvian conduction aphasics are superior to infrasylvian conduction aphasics in the token test and in repetition tasks. Infrasylvian conduction aphasics use more stereotypes in spontaneous speech than suprasylvian conduction aphasics. Conduction aphasics with both lesion sites perform less well in tests of naming, writing, and comprehension than the pure types. Thus conduction aphasia is a heterogeneous syndrome anatomically and linguistically.

Adult↗

PubMed2001

3D-VIEWER: an atlas-based system for individual and statistical investigations of the human brain.

3D-VIEWER is a new software tool for neurosurgical planning and population studies. It is based on digitized three-dimensional brain atlases derived from standard stereotactic atlases that can be adapted to an individual's brain and shown as a series of displayed images. If the patient's brain has been imaged in different modalities, the standardized anatomical information can be adapted to the individual images, which will bring the images into registration. The 3D-VIEWER can be used as a tool for combining multimodal information from the same patient. In addition, several tools are available that allow oblique views of anatomical structures or the view along the intended trajectory during a neurosurgical intervention. Furthermore, using the atlas transformation matrices, anatomical information can be determined when comparing an individual's brain to the anatomy of the atlas brain. Thus, standardized anatomical information from the atlas can be introduced into individual images. This standardization is used to perform individual-group and group-by-group comparisons between patients and normal controls in anatomical studies.

Brain Mapping↗

PubMed2000

Visualization of nerve fiber orientation in gross histological sections of the human brain.

Diffusion weighted magnetic resonance imaging (DWMRI) allows visualization of the orientation of the nervous fibers in the living brain. For comparison, a method was developed to examine the orientation of fibers in histological sections of the human brain. Serial sections through the entire human brain were analyzed regarding fiber orientation using polarized light. Direction of fibers in the cutting plane was obtained by measuring the azimuth with the lowest intensity value at each point, and inclination of fibers in the section was evaluated using fuzzy logic approximations. Direction and inclination of fibers revealing their three-dimensional orientation were visualized by colored arrows mapped into the images. Using this procedure, various fiber tracts were identified (pyramidal tract, radiatio optica, radiatio acustica, arcuate fascicle, and 11 more). Intermingled fibers could be separated from each other. The orientation of the fiber tracts derived from polarized light microscopy was validated by confocal laser scanning microscopy in a defined volume of the internal capsule, where the fiber orientation was studied in four human brains. The polarization method visualizes the high degree of intermingled fiber bundles in the brain, so that distinct fiber pathways cannot be understood as solid, compact tracts: Neighbouring bundles of fibers can belong to different systems of fibers distinguishable by their orientation.

Aged↗

PubMedDate not supplied

Spatial registration of digital brain atlases based on fuzzy set theory.

We present a semiautomatic method based on fuzzy set theory for adjusting a computerized brain atlas to magnetic resonance images (MRIs) of the human cerebral cortex. The atlas was registered to three-dimensional MRI data sets of 10 healthy volunteers. After a global matching using the external contour of the brain, several local procedures were performed regarding selected primary furrows and cytoarchitectonic areas. The final transformation matrix was calculated with respect to these anatomical structures and to their local matrices. Evaluation revealed an increase in accuracy as expressed by a reduction of the visible mismatch with respect to the registration of cortical and subcortical brain structures.

Atlases as Topic↗

PubMedDate not supplied

Fuzzy sets in human anatomy.

Artificial intelligence will have a great impact on the rather traditional field of anatomy. Techniques of artificial intelligence can advance anatomical research in a wide range of applications. Fuzzy logic is especially useful in facilitating the use of natural language in the mathematical description of structures or functions. Examples presented demonstrate the broad use of information technology in anatomical applications, including description and classification, knowledge representation, image processing, and three-dimensional anatomical atlases.

Anatomy↗