TRADITIONAL POSTER - ismrm

Poster Sessions
3154. Consistency Assessment for R 2 * Measurements Obtained with Different Techniques at 7 Tesla
Xiangyu Yang 1 , Petra Schmalbrock 1 , Michael V. Knopp 1
1 Department of Radiology, The Ohio State University, Columbus, OH, United States
At high and ultrahigh field, R 2 * measurement can be dependent on the technique used due to non-exponential FID distortions caused by various factors. In
this study, we compared R 2 * measurements obtained with three different techniques in a group of four healthy volunteers at 7 Tesla to assess their
consistency. Our results demonstrate that R 2 * values measured with a 2D imaging technique is only comparable with those from a 3D technique when
appropriate correction for the background field inhomogeneity effect is applied.
3155. Analysis of Abdominal Fat Tissue Images Acquired with Continuously Moving Table MRI
Stathis Hadjidemetriou 1 , Juergen Hennig 1 , Florian Klausmann 1 , Ute Ludwig 1
1 Department of Diagnostic Radiology, University Hospital Freiburg, Freiburg, Germany
The risk for hypertension and diabetes is correlated closely to the amount of visceral fat. In this work, the abdominal fat is imaged with a continuously
moving table whole body MRI technique. A method is presented for the repeatable, general, and reliable differentiation of lipids into subcutaneous and
visceral. The data is restored for intensity uniformity. The corrected image is processed to segment the body region with the graph cuts algorithm operating
on level sets. Then, the contour separating the subcutaneous and visceral fat regions is identified with a combination of the random walks algorithm and
graph cuts.
3156. Fast Fat/Water Decomposition Using GPU Computation and Newton's Method
David Johnson 1 , Sreenath Narayan 2 , Chris Flask, 2,3 , David Wilson 2,3
1 Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States; 2 Biomedical Engineering, Case Western
Reserve University, Cleveland, OH, United States; 3 Radiology, University Hospitals of Cleveland, Cleveland, OH, United States
An improved fat/water estimation technique was developed using Iterative Decomposition of Water and Fat with Echo Asymmetry and Least-squares
estimation method and Graphics Computational Units (IDEAL-GPU). The IDEAL-GPU technique produced robust fat and water images quickly and
efficiently using a vectorized equation implemented on graphics cards. In addition, our implementation used binary weighted planar extrapolation for robust
estimation in the face of large field variations on a high field, small animal scanner. Fast computation will become even more significant as the trend towards
high resolution, whole body mouse and human scanning continues.
3157. Case-PDM Optimized Compressed Sensing Sampling for Fat-Water Separation
Sreenath Narayan 1 , Jun Miao 1 , Fangping Huang 1 , David Johnson 2 , Guo-Qiang Zhang 1 , David Wilson 1
1 Case Western Reserve University, Cleveland, OH, United States; 2 Ohio State University, Columbus, OH, United States
Compressed Sensing for 3 point Dixon method source image reconstruction has not yet been optimized for perceptual performance. In this abstract, we
determine how to densely to sample each of the source images to achieve a given global sampling ratio.
3158. Comparison of Compressed Sensing and Keyhole Methods for Fat-Water Separation
Sreenath Narayan 1 , Jun Miao 1 , Fangping Huang 1 , David Johnson 2 , Guo-Qiang Zhang 1 , David Wilson 1
1 Case Western Reserve University, Cleveland, OH, United States; 2 Ohio State University, Columbus, OH, United States
Dixon-type methods require multiple scans with different chemical shift weights. Keyhole methods have previously been used to reduce scan time. In this
abstract, we compare keyhole methods and Compressed Sensing for quantitative studies.
Brain Image Analysis
Hall B Thursday 13:30-15:30
3159. Methodology for the Estimation of the Extension of a White Matter Tract Into and Through
Associated Grey Matter
Daniel J. Tozer 1 , Declan Chard 1 , Olga Ciccarelli 2 , Benedetta Bodini 2 , David H. Miller 1 , Alan J.
Thompson 2 , Claudia Angela Michela Wheeler-Kingshott 1
1 NMR Unit, Department of Neuroinflammation, UCL Institute of Neurology, London, United Kingdom; 2 Brain Repair and
Rehabilitation, UCL Institute of Neurology, London, United Kingdom
The definition of areas of grey matter (GM) that are associated with specific white matter tracts is important for studies investigating the spatio-temporal
relationship between the two. The work proposes a method for extending a white matter tract calculated from diffusion MRI through the GM using a
geometrical extension of those pixels on the tract edge, which are in or abut GM, to the nearest point on the outer GM boundary. It was found that running
the extension in 3 orthogonal 2D planes included more tissue than running the process in 3D, which may be preferable in many cases.
3160. New Invariant Indexes to Quantify Water Anomalous Diffusion in Brain
Silvia De Santis 1,2 , Silvia Capuani 1,2 , Andrea Gabrielli 3,4 , Bruno Maraviglia, 1,5
1 Physics department, Sapienza University, Rome, Italy; 2 INFM-CNR SOFT, Sapienza University, Rome, Italy; 3 SMC - CNR/INFM,
Sapienza University, Rome, Italy; 4 ISC - CNR, Rome, Italy; 5 Neuroimaging Laboratory, S. Lucia Foundation, Rome, Italy
We propose a new procedure to detect the deviation from the mono-exponentiality of water diffusion in brain. The stretched-exponential model has been
extended to three-dimensional space to obtain new scalar invariants. The potentiality of this methodology has been evaluated on young healthy subjects.
Statistical analysis on selected ROIs from different cerebral tissues underlined a different contrast compared to conventional DTI one. In particular, GM and
WM can be discriminated on the basis of their microstructural complexity, underlying a chance for investigating subtle changes of the water diffusive
motion in tissues which are not detected by conventional MD and FA indexes.