ELECTRONIC POSTER - ismrm

IDEAL knee MRI data is proposed. Variation in the characteristics of similar structures in IDEAL water and fat images is used to
generate the guidance map for automated segmentation. Segmented structures are analyzed qualitatively and quantitatively with
manually segmented datasets from GE 1.5T scanner. Reported DSC with the experimental datasets (>85%) indicates that the proposed
solution improved the robustness of segmentation.
Contrast Mechanisms
Hall B Monday 14:00-16:00 Computer 127
14:00 5119. The Effect of NMR-Invisible Susceptibility Inclusions on Phase Maps.
Samuel James Wharton 1 , Richard Bowtell 1
1 Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, United Kingdom
Phase images generated at high field show exquisite anatomical contrast resulting from small changes of the NMR frequency linked to
variation of the local magnetic susceptibility across tissues. When a significant contribution to the average susceptibility comes from
NMR-invisible inclusions, the average NMR frequency offset is not however simply proportional to the average susceptibility. Here,
we derive a simple expression based on the use of the conventional sphere of Lorentz, which allows the average NMR frequency
offset to be calculated for compartments containing inclusions of varying shape and concentration. The expression is tested by
comparison with the results of simulations.
14:30 5120. MRI Signal Response Mapping (SIRMA) to Dephaser to Quantify Susceptibility
Gradient
florence franconi 1 , Jean-Jacques Le Jeune 2 , Pascal Richomme 1 , Laurent Lemaire 2
1 PIAM, Université d'Angers, Angers, France, Metropolitan; 2 UMR-S646, INSERM, Angers, France
SIgnal Response MApping to dephaser (SIRMA) method is proposed to quantify susceptibility gradient. In gradient echo acquisitions,
the SIRMA method measures the echo shifts in k-space of susceptibility affected spins from a series of dephased images collected
with additional incremental slice refocusing gradient offset or incremental reconstruction window off-centering. SIRMA applicability
and performances have been demonstrated in vitro through quantization of susceptibility gradient induced in a cylinder model and in
vivo through the quantitative detection of SPIO distribution volume. With respect to its quantitative nature, its computational
simplicity, this method deserves further attention for application in molecular or cellular imaging.
15:00 5121. Simultaneous δR1 and δR2* Quantification in 5s to Monitor Blood and Tissue
Oxygenation with Dynamic (C)O 2 Enhanced MRI
Stefanie Remmele 1 , Tobias Voigt 2 , Jochen Keupp 1 , Christian Stehning 1 , Julien Sénégas 1
1 Philips Research Europe, Hamburg, Germany; 2 University of Karlsruhe, Karlsruhe, Germany
This work presents an approach to simultaneous and dynamic dR1, dR2* estimation that combines the beneficial features of currently
used techniques for dynamic R1 quantification in DCE-MRI and for dynamic R2*-quantification in D(C)O2E-MRI. The technique
aims at increasing the specificity of R2* BOLD imaging during respiratory challenges. Its accuracy and sensitivity is evaluated in
phantom and breathold experiments.
15:30 5122. Susceptibility Weighted Imaging and Susceptibility Mapping (SWIM): A New
Means to Visualize Veins and Quantify Susceptibility
Ewart Mark Haacke 1,2 , Jin Tang 3 , Yu-Chung Norman Cheng 1 , Jaladhar Neelavalli 2,4
1 Academic Radiology, Wayne State University, Detroit, MI, United States; 2 The MRI Institute for Biomedical
Research, Detroit, MI, United States; 3 McMaster University, Hamilton, Ontario, Canada; 4 Nuffield Department
of Surgery, University of Oxford, Oxford, United Kingdom
A new means of visualizing veins which is independent of orientation of vessels (or the head) relative to the main magnetic field is
presented. This new venous imaging method is based on direct mapping of the susceptibility using the inverse Green’s function
approach.
Tuesday 13:30-15:30 Computer 127
13:30 5123. Feasibility of Brain Lesion Characterization at 1.5T – Whole-Brain Susceptibility
Mapping Using A Homogeneous Lesion Constraint
Ferdinand Schweser 1 , Andreas Deistung 2 , Berengar Wendel Lehr 2 , Jürgen Rainer
Reichenbach 2
1 Medical Physics Group, Department of Diagnostic and Interventional Radiology , Jena University Hospital,
Jena, Germany; 2 Medical Physics Group, Department of Diagnostic and Interventional Radiology, Jena
University Hospital, Jena, Germany
A method is presented for high-quality whole-brain susceptibility mapping based on standard clinical single-shot low-field SWI-data.
Feasibility of in-vivo lesion characterization is demonstrated for clinical patient data.