TRADITIONAL POSTER - ismrm

Poster Sessions
Electron Spin Resonance
Hall B Thursday 13:30-15:30
1034. Non-Invasive Demonstration of Instabilities in Tumor Oxygen Concentration Using Dynamic 3D EPR
Oxygen Imaging
Hironobu Yasui 1,2 , Shingo Matsumoto 1 , Jeeva P. Munasinghe 3 , Nallathamby Devasahayam 1 , Sankaran
Subramanian 1 , James B. Mitchell 1 , Murali C. Krishna 1
1 National Cancer Institute, Bethesda, MD, United States; 2 Hokkaido University, Hokkaido, Japan; 3 National Institute of Neurological
Disorder and Stroke
Structural and functional abnormality of blood vessels within malignant tumors influences delivery of oxygen, a key radio-sensitizer, resulting in two
different types of hypoxia. Chronic hypoxia is attributed to large diffusion distances between tumor microvessels and longitudinal oxygen gradient, whereas
acute hypoxia is though to be the result of transient vascular occlusion and fluctuation in red blood cell flux. Electron paramagnetic resonance (EPR)
imaging is a sensitive method to non-invasively map tissue oxygenation distribution. To investigate the fluctuation of tumor oxygen concentration, dynamic
3D EPR oxygen imaging was applied to two different types of tumor bearing in mouse.
1035. Assessment of Rapamycin Effects on Tumor Oxygenation and Angiogenesis by Using EPRI and MRI
Keita Saito 1 , Shingo Matsumoto 1 , Nallathamby Devasahayam 1 , Sankaran Subramanian 1 , Jeeva P.
Munasinghe 2 , Vyomesh Patel 3 , Silvio Gutkind 3 , James B. Mitchell 1 , Murali C. Krishna 1
1 National Cancer Institute, Bethesda, MD, United States; 2 National Institute of Neurological Disorder and Stroke; 3 National Institute
of Dental and Craniofacial Research
Effects of anti-tumor drug rapamycin on tumor oxygenation and angiogenesis in tumor bearing mice were investigated by using pulsed electron spin
resonance imaging and magnetic resonance imaging. Blood volume in tumor region was significantly decreased after 2 days from beginning of the
rapamycin treatment. Tumor oxygenation did not drastically change by rapamycin treatments, but pO 2 level slightly increased and the ratio of hypoxic area
to tumor region slightly decreased after 2 days rapamycin treatments. These results suggest that rapamycin can normalize blood volume and suppress
depletion of oxygen in the tumor region.
1036. Spatial Distribution of Free Radicals in Dental Resins Using Electron Paramagnetic Resonance
Imaging (EPRI)
Philippe Levêque 1 , Julian Leprince 2,3 , Ana Maria Dos Santos-Goncalvez 2 , Gaëtane Leloup 2 , Bernard
Gallez 1
1 Biomedical magnetic resonance unit, Université catholique de Louvain, Brussels, Belgium; 2 School of Dentistry and Stomatology,
Université catholique de Louvain, Brussels, Belgium; 3 Laboratory of Polymer Science, Université catholique de Louvain, Louvain-la-
Neuve, Belgium
Methacrylate resins are highly popular in dentistry and are largely used in clinic for tooth restoration. Free radicals are created during the
photopolymerization process and can be detected by EPR spectroscopy. EPR has been successfully used to study the mechanical properties of this material.
This study focuses on the feasibility of EPRImaging using dental resins which exhibits complex signal. 2D imaging and 2D spectral spatial imaging were
applied and give the unique possibility of non destructive characterization and mapping of free radicals in dentam resins and more generally in biomaterials
and materials science.
Microscopy
Hall B Monday 14:00-16:00
1037. Characterization of Tumor Microvascular Structure and Permeability by MRI and Intravital Confocal
Imaging
Nina Kristine Reitan 1 , Marte Thuen 2 , Pål Erik Goa 3
1 Department of Physics, NTNU, Trondheim, Norway; 2 Department of Circulation and Medical Imaging, NTNU, Trondheim, Norway;
3 Department of Radiology, St. Olavs Hospital, Trondheim, Norway
By using confocal laser scanning microscopy (CLSM) and MRI we studied microvascular architecture and permeability in tumors growing in dorsal window
chambers in mice. 40 kDa dextran and Gadomer was used as molecular tracers for dynamic CLSM and DCE-MRI, respectively. Correlation was found
between permeability measured by the two techniques and permeability further depended on structural parameters, like fractal dimension and vascular
density. This study demonstrates that the dorsal window tumor model gives an opportunity to use CLSM and MRI as supplementary techniques and that
CLSM provides insight into the spatial heterogeneous microenvironment on a microscopic level that is not accessible with MRI.