Microbubbles as novel pressure-sensitive MR contrast agents
| Autor: | Andrew L. Alexander, Thomas T. McCreery, Arthur F. Gmitro, Evan C. Unger, Terry R. Barrette |
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| Rok vydání: | 1996 |
| Předmět: |
Liposome
Perfluorobutane chemistry.chemical_element Contrast Media Magnetostatics Magnetic susceptibility Magnetic Resonance Imaging Sulfur hexafluoride chemistry.chemical_compound Neon Nuclear magnetic resonance Xenon chemistry Liposomes Microbubbles Pressure Radiology Nuclear Medicine and imaging Gases Physics::Chemical Physics |
| Zdroj: | Magnetic resonance in medicine. 35(6) |
| ISSN: | 0740-3194 |
| Popis: | Magnetic resonance imaging contrast agents that are sensitive to pressure would be useful for evaluating cardiovascular function. One such potential contrast agent consists of gas-filled liposome microbubbles. The magnetic susceptibility of the microbubbles locally perturb the static magnetic field, which influences the transverse-relaxation properties of the surrounding medium. Changes in the pressure alter the bubble dimensions, which affects the magnetic field perturbations and, hence, the transverse-relaxation. The effect of these microbubbles on the T2 relaxation times of a water-based medium was measured for liposomes filled with different gases-nitrogen, argon, air, oxygen, xenon, neon, perfluoropentane, perfluorobutane, and sulfur hexafluoride. The air-filled, perfluoropentane-filled and the oxygen-filled liposomes demonstrated the largest effect on transverse-relaxation. The influence of pressure on both gradient-echo and spin-echo signal intensities for air-filled microbubbles was also evaluated. Pressure-induced changes in signal intensity were consistently observed for both the spin-echo and gradient-echo pulses sequences. |
| Databáze: | OpenAIRE |
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