This file was created by the Typo3 extension sevenpack version 0.7.14 --- Timezone: CEST Creation date: 2013-06-20 Creation time: 10-25-46 --- Number of references 8 article 3809 Physical Review B 2005 9 72 12 125115 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft SLeyer SHeck akaiserAKaiser EDormann RGBarnes article 3808 Physical Review B 2005 3 71 11 115108 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft akaiserAKaiser EDormann article 3803 Journal of Physics-Condensed Matter 2003 10 15 41 7085 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft akaiserAKaiser TWokrina BPongs EDormann article 3805 Synthetic Metals 2001 10 124 2-3 311 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft akaiserAKaiser GFischer EDormann article 3806 Physics Letters A 2001 4 282 1-2 125 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Biologische Kybernetik Max-Planck-Gesellschaft akaiserAKaiser BPongs GFischer EDormann inproceedings 3804 Synthetic Metals 2003 2 135-136 547 http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de International Conference on Science and Technology of Synthetic Metals, Shanghai 2002 Biologische Kybernetik Max-Planck-Gesellschaft ICSM 2002 akaiserAKaiser BPongs EDormann poster HaroonMKALP2008 2008 5 16 3369 543 We present a study attempting to validate the corticocortical connection information obtainable from diffusion-weighted MR data. We have implemented probabilistic tractography in data acquired in a macaque model and compared this with connection information in a database of invasive tracer studies in the same model. The nature of the corticocortical interconnection information gained from probabilistic tractography is different to that gained from invasive studies, the latter also being sparse. Our results using the LVE00a parcellation scheme indicate that probabilistic tractography is able to give statistically comparable information on corticocortical interconnections to invasive tracer studies. http://www.kyb.tuebingen.mpg.defileadmin/user_upload/files/publications/ISMRM-2008-03369.pdf http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.ismrm.org/08/ Toronto, Canada 16th Scientific Meeting and Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM 2008) HAHaroon DMMorris akaiserAKaiser markMAugath nikosNKLogothetis GJMParker poster 4167 Magnetic Resonance Materials in Physics, Biology and Medicine 2006 9 19 Supplement 1 328 Purpose/Introduction: Short acquisition times and short effective echo times are of prime importance for functional MR imaging studies of the brain to reduce distortion artifacts and increase SNR. The spiral sequence, specifically in the segmented version, offers these features and presents itself in specific applications as an alternative to conventional EPI. Spiral imaging is also less prone to flow and motion artifacts. But this method is more demanding on the exact gradient performance and correction mechanisms need to be implemented to achieve necessary readout gradient corrections. Subjects and Methods: To test and illustrate the performance of the implemented corrections, a geometry phantom was measured with a spin echo sequence as a reference and compared with a segmented spiral-out sequence. The measurements were performed on a 7T/ 60 cm Bruker Biospec vertical wide bore monkey MR system. A saddle coil was used in transmit and receive mode. Measurements of the k-space trajectories and images were performed[1]. With the k-space trajectory of the readout gradient the deviation from the theoretical course were calculated. From these the k-space offset, the time delay and the slope and baseline of the gradient courses were derived. The latter is done by comparing trajectories with positive and negative amplitudes. These corrections were then applied for spiral image acquisition and reconstruction. Results: The image where no corrections are applied (Fig.1, middle) shows that the edges of the rectangle inside the phantom are reproduced sharp and at the first look not distorted. It reveals although that the geometry is not at all correct compared to the reference image gained by the MSME sequence (Fig.1, left). Regarding the edges of the phantom in the lower part of the image a strong blurring occurs. Performing now the corrections before acquiring and before reconstructing the image the geometry is reproduced satisfactorily (Fig.1, right). The blurring artifact at the lower edge of the phantom is nearly fully eliminated. Discussion/Conclusion: The measurements of the trajectories and images on a geometry phantom show the efficiency of the corrections. Blurring artifacts are reduced. A misleading geometry like for an image measured with an uncorrected spiral-out EPI sequence can be avoided by applying the corrections. The corrections enable the spiral imaging sequence to be an alternative to conventional EPI in specific applications utilizing short echo times. [1] Takahashi A. et al. MagnResonMed 1995;34:446-456. http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de http://www.kyb.tuebingen.mpg.de Department Logothetis http://www.springerlink.com/content/n70r05532r7q6425/fulltext.pdf Biologische Kybernetik Max-Planck-Gesellschaft Warsaw, Poland 23rd Annual Scientific Meeting of the ESMRMB 2006 en 10.1007/s10334-006-0043-1 akaiserAKaiser tramTNguyen nikosNKLogothetis josefJPfeuffer