TRADITIONAL POSTER - ismrm

Poster Sessions
1672. Towards Image-Dependent Safety Hulls for Fiber Tracking
Sebastiano Barbieri 1 , Jan Klein 1 , Christopher Nimsky 2 , Horst K. Hahn 1
1 Fraunhofer MEVIS - Institute for Medical Image Computing, Bremen, Germany; 2 Department of Neurosurgery, University Marburg,
Marburg, Germany
We make use of a DTI software model in order to systematically analyze the influence of noise, fiber bundle diameter, number of seed points and tensor
anisotropy on the magnitude of fiber tracking errors. In our model we simulate image noise and partial volume artifacts. As a measure for fiber tracking
errors we introduce a so called "safety radius". The safety radius is used to construct safety hulls, which are tubes that surround the tracked fibers and
indicate their margin of error. We further analyze how fibers are spatially distributed inside a cylindrical fiber bundle during the tracking process.
1673. Atlas-Guided Automated Tract Reconstruction of the White Matter Anatomy
Yajing Zhang 1 , Kenichi Oishi 2 , Michael I. Miller 3 , Jiangyang Zhang 4 , Susumu Mori 2,5
1 Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States; 2 Radiology and Radiological
Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States; 3 Center for Imaging Science, Johns Hopkins
University, Baltimore, MD, United States; 4 Radiology and Radiological Science, , Johns Hopkins University School of Medicine,
Baltimore, MD, United States; 5 F.M.Kirby Resarch Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD,
United States
We performed comprehensive studies of human white matter anatomy using a novel atlas based automated fiber tracking system. 130 3-D ROIs were
transformed from our brain atlas to the individual subject using non-linear transformations and used for automated fiber tracking. This approach allows
exhaustive search of white matter bundles that consistently exist in the normal population. The method was validated by comparing to manual results by
experts. We identified 29 short cortico-cortical association fibers in addition to well-defined major bundles. Probabilistic maps of such tracts in normalized
space were constructed for the first time in the normal population.
1674. Global Fiber Tracking Becomes Practical
Marco Reisert 1 , Irina Mader 2 , Constantin Anastasopoulus 2 , Susanne Schnell 1 , Valerij Kiselev 1
1 Medical Physics, University Hospital Freiburg, Freiburg, Baden-Wuerttemberg, Germany; 2 Section of Neuroradiology, University
Hospital Freiburg
Local fiber tracking approaches are based on the 'walker' principle, the fibres are reconstructed path-by-path by small successive steps along the tracts. On
the other hand global ideas try to reconstruct all fibres at once by optimizing a certain global objective. Local algorithms are fast but suffer from accumulated
errors. Global methods have a more sound foundation but are very complex to optimize. This abstract presents an approach, which fuses both ideas while
keeping their advantages. The experiments show that the approach is orders of magnitude faster than recent global approaches while improving the detection
performance.
1675. Probabilistic Connectivity in Fibre Tractography
Parya MomayyezSiahkal 1 , Kaleem Siddiqi 1
1 School of Computer Science, Centre for Intelligent Machines, McGill University, Montréal, Quebec, Canada
We introduce a probabilistic connectivity index between two regions, based on diffusion MRI, by using a stochastic nonlinear differential equation to model
the Brownian motion of water molecules in a medium. The model is linked to the physical basis of the diffusion process and leads to promising results on the
MICCAI 2008 Fibre cup phantom. Our experiments yield highly curving fibre tracts without the need to impose thresholds on curvature or torsion or to
eliminate false positives. An additional benefit is the algorithm's low computational complexity and the fact that its parameters are data-driven and are
selected automatically.
1676. Analysis of Connectivity of Gray Matter Regions Using DTI and Graph Theory
Amy Kuceyeski 1 , Ashish Raj 1
1 Radiology, Weill Cornell Medical College, New York, NY, United States
The connectivity of gray matter regions in the brain via white matter tracts has recently become an area of wide interest due to the advances in imaging
techniques that measure structural connections via white matter (DTI. The information that can be extracted from this modality has not yet been harvested
fully due to its relative novelty; however some studies have proven its potential. We propose a computational methodology that utilizes DTI and structural
images of the brain, graph theory, and clustering algorithms to explore regions of high connectivity and importance to overall connectivity in normal brains.
1677. Fiber Tracking of Human Brain Using Moment-Based Orientation Distribution Function and Multi-
Shelled Q-Ball Imaging
Eizou Umezawa 1 , Yoshifumi Kuwayama 2 , Akihito Yamamoto 2 , Hikaru Masumoto 2 , Takashi Fukuba 2 ,
Masao Ohashi 2 , Keiko Terada 2 , Toshiaki Mori 2 , Yutaka Kinomura 2 , Kojiro Yamaguchi 1 , Masayuki
Yamada 1 , Hirofumi Anno 1 , Kazuhiro Katada 3
1 School of Health Sciences, Fujita Health University, Toyoake, Aichi, Japan; 2 Radiological Division, Fujita Health University
Hospital, Toyoake, Aichi, Japan; 3 Department of Radiology, School of Medicine, Fujita Health University, Toyoake, Aichi, Japan
Multi-Shelled QBI (MS-QBI) gives a new orientation distribution function based on the moment of the probability density function. We perform the fiber
tracking of human brain based on MS-QBI and confirm the practicability of the method. We implement a simple procedure for streamline fiber trackings of
pathways that encounter crossings. The pyramidal tract (PT) can be traced beyond the crossing with the superior longitudinal fasciculus by MS-QBI. The
distinction between PT and the corpus callosum in the corona radiata is still difficult.