ISMRM 21st Annual Meeting & Exhibition 20-26 April 2013 Salt Lake City, Utah, USA

Contrast Generation & Elastography
Friday 26 April 2013
Room 355 BC  10:30 - 12:30 Moderators: Jongho Lee, Jesse L. Wei

10:30 0864.   
2-In-1: Simultaneously T2/T2* Weighted Double Echo Fast Spin Echo Imaging
Katharina Fuchs1, Fabian Hezel1, Sabrina Klix1, and Thoralf Niendorf1,2
1Berlin Ultrahigh Field Facility (B.U.F.F.), Max-Delbrueck Center for Molecular Medicine, Berlin, Germany, 2Experimental and Clinical Research Center, a cooperation of the CharitÚ Medical Faculty and the Max-Delbrueck Center for Molecular Medicine, Berlin, Germany

Both T2 and T2* weighted Fast Spin Echo (FSE) sequences are frequently applied in clinical practice. This work presents an FSE technique which is simultaneously sensitive to T2and T2* offering various applications including simultaneous mapping. The dual weighting of the proposed two-in-one sequence is generated via the separation of spin echoes and stimulated echoes. Applicability of the presented approach is examined in phantoms and healthy volunteers at 3.0 T and 7.0 T.

10:42 0865.   
T2-Weighted Fat Suppressed Balanced SSFP Imaging (Contrast-Prepared SSFP) for Interventional Guidance
Di Xu1, Clifford R. Weiss2, Ozan Sayin1, Wesley D. Gilson3, Jonathan S. Lewin2, Elliot R. McVeigh1, and Daniel A. Herzka4
1Biomedical Engineering, The Johns Hopkins School of Medicine, Baltimore, MD, United States, 2Radiology, The Johns Hopkins School of Medicine, Baltimore, MD, United States,3Siemens Corporation, Corporate Technology, Baltimore, MD, United States, 4Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States

T2-weighted fat suppressed MR images are diagnostically relevant in lesion and critical structure characterization in vascular anomalies, oncology, and cardiology, etc. Current techniques used in MR-guided interventions have limited T2 contrast and fat suppression (e.g SSFP), are slow (e.g. T2W-TSE), or yield blurry images and inferior speed (HASTE). Hence, an imaging technique with sufficient speed for real-time procedure guidance in addition to T2 contrast and fat suppression is of interest. We present contrast-prepared SSFP (CP-SSFP), a technique for interventional guidance incorporating several technical improvements. The technique is evaluated on phantoms and patients undergoing therapeutic or diagnostic imaging for vascular malformations.

10:54 0866.   On the Role of Neuronal Magnetic Susceptibility and Structure Symmetry on Gradient Echo MR Signal Formation
Alexander L. Sukstanskii1 and Dmitriy A. Yablonskiy1
1Radiology, Washington University, St. Louis, Missouri, United States

In this communication we analyze the effect of magnetic anisotropy associated with the presence of radially-oriented long-chain lipoprotein molecules in the myelin sheath of WM fibers on gradient echo MRI signal formation. We incorporate this effect into previously developed Generalized Lorentzian approach and calculate water frequency shifts in axons, myelin and extracellular space. Frequency shifts in axons and myelin sheath are shown to be highly anisotropic with respect to B0. Importantly, both the cylindrical symmetry of WM tissue structure and of magnetic susceptibility contribute to this anisotropic effect. It is also shown that myelin water signal is substantially non-T2* type.

11:06 0867.   
Background-Suppressed Myelin Water Imaging
Se-Hong Oh1 and Jongho Lee1
1Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States

In this study, a new MRI sequence that selectively acquires myelin water signal is proposed. Compared to conventional myelin water imaging, the new myelin water imaging method provides substantially improved image quality showing potentials for clinical applications.

11:18 0868.   
Differential Developmental Trajectories of Magnetic Susceptibility in Human Brain Gray and White Matter
Wei Li1, Bing Wu2, Anastasia Batrachenko1, Christian Langkammer3, Stefan Ropele3, Rajendra Morey1,4, Vandana Shashi5, Allen W. Song1,6, and Chunlei Liu1,6
1Brain Imaging & Analysis Center, Duke University, Durham, North Carolina, United States, 2GE Healthcare China, Beijing, China, 3Neurology, Medical University of Graz, Graz, Austria, 4Psychiatry and Behavioral Sciences, Durham VA Medical Center, Durham, North Carolina, United States, 5Pediatrics, Duke University, Durham, North Carolina, United States, 6Radiology, Duke University, Durham, North Carolina, United States

The evolution of regional magnetic susceptibility in the human brain is assessed in 181 subjects from 1 to 83 years. The evolution of magnetic susceptibility over the lifespan was found to display differential trajectories between gray and white matter. Both cortical and subcortical white matter showed an initial decrease followed by a subsequent increase of magnetic susceptibility, while both cortical gray matter and iron-rich deep nuclei displays a monotonic increase. These results suggest that magnetic susceptibility may provide valuable information regarding the spatial and temporal patterns of brain myelination and iron deposition during brain maturation and ageing.

11:30 0869.   MRI Contrasts Generated Using Fictitious Fields in High-Rank Rotating Frames Correlate with Myelin Content in Normal Rat Brain ex vivo
Timo Liimatainen1, Alejandra Sierra1, Hanne Hakkarainen1, Djaudat Idiyatullin2, Christine Storino2, Silvia Mangia2, Olli Gr÷hn1, Michael Garwood2, and Shalom Michaeli2
1A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Fi, Finland, 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

Relaxation Along a Fictitious Field (RAFF) was used to characterize MRI tissue contrast in a rotating frames of rank n, where n was varied between 1 and 5. Relaxation times maps in high-rank rotating frames correlate with myelin content in the rat brain ex vivo better than T1, T2, T1lower case Greek rho, T2lower case Greek rho or MT. The RAFFn provides high potential for mapping of myelination in the brain.

11:42 0870.   MR Elastography as a Method to Estimate Brain Stiffness and Its Correlation to Intracranail Pressure in Pseudotumor Ceribri Patients
Wael Marashdeh1, Bradley Gans1, Brian Raterman1, Eric Bourekas1, and Arunark Kolipaka1
1Radiology, ohio state university wexner medical center, Columbus, ohio, United States

Measuring the stiffness of the brain provides important diagnostic information.Magnetic Resonance Elastography(MRE)is a noninvasive method to estimate the stiffness of the brain.This study aims to determine the correlation between intracranial pressures and whole brain stiffness.Our results demonstrated no significant difference in MRE derived brain stiffness to the opening and closing intracranial pressures measured by lumbar puncture in a pool of 7 patients. However, more studies are warranted to establish the correlation between intracranial pressure and brain stiffness.

11:54 0871.   Selective Spectral Displacement Projection in 3D Multifrequency MRE
Temel Kaya Yasar1, Dieter Klatt2, Richard L. Magin2, and Thomas J. Royston2
1Department of Mechanical & Industrial Engineering, The University of Illinois at Chicago, Chicago, Illinois, United States, 2Department of Bioengineering, The University of Illinois at Chicago, Chicago, Illinois, United States

We introduce selective spectral displacement projection (SDP) as a new motion encoding concept for 3D multifrequency MRE. SDP-MRE can be applied to a vibration spectrum composed of three frequencies and exploits the filter condition of MRE for selecting one frequency each per spatial direction. The selected components are simultaneously encoded in the phase of the MR signal and the acquisition of temporally-resolved phase images enables the decomposition of the individual components. SDP-MRE reduces the number of temporally-resolved MRE experiments for data acquisition by a factor of 3, while providing the same wave images as found using conventional monofrequency MRE.

12:06 0872.   Detection of Amyotrophic Lateral Sclerosis Using in vivo Waveguide Elastography
Anthony J. Romano1, Jing Guo2, Torben Prokscha3, Sebastian Hirsch4, Juergen Braun5, Ingolf Sack3, and Michael Scheel3
1Physical Acoustics, Naval Research Laboratory, Washington, DC, United States, 2Department of Radiology, Charite - University Medicine Berlin, Berlin, Germany, 3Department of Radiology, Charite-Universitatsmedizin, Berlin, Germany, 4Department of Radiology, CharitÚ - Universitńtsmedizin Berlin, Berlin, Germany, 5Institute of Medical Informatics, Charite - University Medicine Berlin, Berlin, Germany

We implemented a method called Waveguide Elastography in the analysis of orthotropic elastic parameters of the corticospinal tracts (CSTs) in the brains of five healthy volunteers. Here, we extend this method in an attempt to detect Amyotrophic Lateral Sclerosis (ALS) by analyzing the stiffness of the CSTs of 10 subjects: These included five healthy controls and five patients who present with ALS. We found that we were able to detect a 5% reduction in shear stiffness in the patients vs the controls, and using a Mann-Whitney-U test, we obtained a p = 0.008 demonstrating significant differences between the two groups.

12:18 0873.   An Atlas of the Anatomy of Human Brain Viscoelasticity
Jing Guo1, Sebastian Hirsch2, Sebastian Papazoglou1, Andreas Fehlner3, Michael Scheel1, Jens Wuerfel4, Juergen Braun5, and Ingolf Sack1
1Department of Radiology, Charite - University Medicine Berlin, Berlin, Berlin, Germany, 2Department of Radiology, CharitÚ - Universitńtsmedizin Berlin, Berlin, Berlin, Germany,3Department of Radiology, CharitÚ University Medicine, Berlin, Berlin, Germany, 4Institute of Neuroradiology, University Luebeck, Luebeck, Schleswig-Holstein, Germany,5Department of Medical Informatics, Charite - University Medicine Berlin, Berlin, Berlin, Germany

We introduce a novel wave field reconstruction method which we used for analyzing 3D-multifrequency MRE brain data of 23 healthy volunteers providing viscoelastic parameter maps with a spatial resolution superior to former approaches. Individual parameter maps reflecting the magnitude of the complex modulus and the powerlaw exponent of the springpot model were normalized and averaged in order to obtain an atlas of the mechanical anatomy of the human brain.