Electron paramagnetic resonance imaging (EPRI) instrumentation, enabling the performance of three-dimensional spectral-spatial images of free radicals, has been developed to study spatially defined differences in tissue metabolism and oxygenation. Using this instrumentation 3D images of nitroxides in rat tail were obtained. The images visualize the arterial and venous vasculature in the tail segment. Based on the exchange broadening influence of oxygen on the EPR linewidth of nitroxides, we performed localized oxygen measurements in the in vivo rat. An oxygen concentration of 300 ± 30 μM was measured in the arteries and 50 ± 20 μM in the veins. These results demonstrate the feasibility of performing in vivo, non-invasive measurements and mapping of localized oxygenation in small animals using spectral-spatial EPR imaging techniques.
ASJC Scopus subject areas
- Biomedical Engineering
- Physics and Astronomy (miscellaneous)
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology