Automatic 3D intersubject registration of MR volumetric data in standardized Talairach space.
ABSTRACT In both diagnostic and research applications, the interpretation of MR images of the human brain is facilitated when different data sets can be compared by visual inspection of equivalent anatomical planes. Quantitative analysis with predefined atlas templates often requires the initial alignment of atlas and image planes. Unfortunately, the axial planes acquired during separate scanning sessions are often different in their relative position and orientation, and these slices are not coplanar with those in the atlas. We have developed a completely automatic method to register a given volumetric data set with Talairach stereotaxic coordinate system.
The registration method is based on multi-scale, three-dimensional (3D) cross-correlation with an average (n > 300) MR brain image volume aligned with the Talariach stereotaxic space. Once the data set is re-sampled by the transformation recovered by the algorithm, atlas slices can be directly superimposed on the corresponding slices of the re-sampled volume. the use of such a standardized space also allows the direct comparison, voxel to voxel, of two or more data sets brought into stereotaxic space.
With use of a two-tailed Student t test for paired samples, there was no significant difference in the transformation parameters recovered by the automatic algorithm when compared with two manual landmark-based methods (p > 0.1 for all parameters except y-scale, where p > 0.05). Using root-mean-square difference between normalized voxel intensities as an unbiased measure of registration, we show that when estimated and averaged over 60 volumetric MR images in standard space, this measure was 30% lower for the automatic technique than the manual method, indicating better registrations. Likewise, the automatic method showed a 57% reduction in standard deviation, implying a more stable technique. The algorithm is able to recover the transformation even when data are missing from the top or bottom of the volume.
We present a fully automatic registration method to map volumetric data into stereotaxic space that yields results comparable with those of manually based techniques. The method requires no manual identification of points or contours and therefore does not suffer the drawbacks involved in user intervention such as reproducibility and interobserver variability.
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ABSTRACT: The human orbitofrontal cortex is an important brain region for the processing of rewards and punishments, which is a prerequisite for the complex and flexible emotional and social behaviour which contributes to the evolutionary success of humans. Yet much remains to be discovered about the functions of this key brain region, and new evidence from functional neuroimaging and clinical neuropsychology is affording new insights into the different functions of the human orbitofrontal cortex. We review the neuroanatomical and neuropsychological literature on the human orbitofrontal cortex, and propose two distinct trends of neural activity based on a meta-analysis of neuroimaging studies. One is a mediolateral distinction, whereby medial orbitofrontal cortex activity is related to monitoring the reward value of many different reinforcers, whereas lateral orbitofrontal cortex activity is related to the evaluation of punishers which may lead to a change in ongoing behaviour. The second is a posterior–anterior distinction with more complex or abstract reinforcers (such as monetary gain and loss) represented more anteriorly in the orbitofrontal cortex than simpler reinforcers such as taste or pain. Finally, we propose new neuroimaging methods for obtaining further evidence on the localisation of function in the human orbitofrontal cortex.Progress in Neurobiology 04/2004; 72(5):341-372. · 10.30 Impact Factor
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ABSTRACT: Segmentación de imágenes de Tomografía Computarizada en pacientes que han sufrido un Accidente Cerebro Vascular Segmentación de imágenes de Tomografía Computarizada en pacientes que han sufrido un Accidente Cerebro Vascular rESUMEN La segmentación de regiones anatómicas en el cerebro que están afectadas por un infarto es un campo complejo debido a la similitud de las tonalidades de la región cerebral y de las características de las imágenes de Tomogra-fía Computarizada (CT). En este proyecto se implemento como solución operaciones morfológicas, umbralización y comparaciones de los hemisferios para poder segmentar de forma efectiva la región afectada. Una vez hecha la segmentación, se construyó una imagen en 3D para visualización y calcular el volumen en porcentaje con respec-to al volumen total del cerebro. Las zonas anatómicas afectadas se obtuvieron a partir del programa de Talairach. ABSTrACT The segmentation of anatomical regions in the brain that are affected by a stroke is a complex field due to the similarity of the tones of the brain region and to the characteristics of CT images. This project was implemented as a solution morphological operations, thresholding and comparison of the hemispheres in order to effectively target the affected region. Once the segmentation, it built a 3D image display and calculate the volume as a percentage of the total volume of the brain. The anatomical areas affected were derived from Talairach program.PROSPECTIVA. 10/2011; 9(2):48-53.
- Scientific Data. 02/2015; 2:150003.