RESUMEN
Magnetic resonance imaging (MRI) is one of the most perspective methods of noninvasive visualization in medicine, and use of contrast agents significantly its potentialities extends. Iron oxide nanoparticles are promising contrast agents, but in fact all the data on their efficiency were obtained in high-field tomographs for experimental animals. We studied the possibility of using magnetic nanoparticles for MRI visualization of rat brain glioblastoma at the most common clinical field 1.5 T The data indicate the efficiency of iron oxide magnetic nanoparticles as contrast agents for 1.5 T MR tomographs.
Asunto(s)
Medios de Contraste/química , Compuestos Férricos/química , Glioblastoma/diagnóstico por imagen , Imagen por Resonancia Magnética/métodos , Nanopartículas de Magnetita/química , Animales , Encéfalo/diagnóstico por imagen , Línea Celular Tumoral , RatasRESUMEN
We studied dependences of T2 relaxation time on magnetic field and concentration of nanoparticles. It was found that nanocontrast media are effective under the influence of the magnetic fields in the range 0.3-7 T. Data of electron paramagnetic resonance confirm the assumption on aggregation of nanoparticles not coated with proteins in high magnetic fields.
Asunto(s)
Medios de Contraste/química , Compuestos Férricos/química , Campos Magnéticos , Imagen por Resonancia Magnética/métodos , Nanopartículas/químicaRESUMEN
In biophysical models and in acute experiments on animals, the air was administered in measured volumes into the artificial blood flow and into the common carotid artery in dogs. When air bubbles get into the electric field between electrodes, specific changes of impedance depending on the bubbles size could be recorded. A lot of small bubbles sharply increased the impedance according to their total volume. Ih the air compression up to 10 kgs/cm2 and in following decompression, the intracranial impedance and pressure smoothly changed according to barogram. After 15 min of stying under pressure the dogs developed during decompression a sharp increase of the intracranial impedance and pressure which, similarly to the results of the model experiments, should be regarded as the consequence of formation of a free gas phase in the system of intracranial circulation.