RESUMO
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.
Assuntos
Meios de Contraste/química , Compostos Férricos/química , Campos Magnéticos , Imageamento por Ressonância Magnética/métodos , Nanopartículas/químicaRESUMO
The new pulse sequence (PS) has been obtained on MRI tomography Ellipse, B=0,15 and Biospec 70/30, B=7 T. The new pulse images of the brain combine features of FLAIR and its sensitivity to magnetic field heterogeneity. We named its PS as the T2 Fluid Attenuation Gradient Echo (T2 FLAGE). The T2 FLAGE characteristics of tissue contrast as well as its efficacy in detection of ICH have been assessed in 57 patients with acute stroke and in 16 experimental rats. The analysis of tissue contrast of lesions and normal brain structure has revealed the greater visibility of T2 FLAGE images compared to FLAIR. At the same time, the images sensitivity of magnetic field heterogeneity is retained. The ROC-analysis has shown that T2 FLAGE images are more effective in differential diagnosis of stroke type compared to FLAIR.
Assuntos
Hematoma/diagnóstico , Hemorragias Intracranianas/diagnóstico , Imageamento por Ressonância Magnética/métodos , Acidente Vascular Cerebral/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Emergências , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , RatosRESUMO
A study aimed at developing the pulse consequence, the double inversion recovery (DIR), using low field magnetic tomography, and assessing its effectiveness in the detection of intracerebral hematoma. The research has been conducted at "Ellipse" MR tomograph. The new pulse sequence has been created by the modification of the regular FLAIR, its technical parameters were as follows: the first TI - 90 ms, the second TI - 1300 ms, TR - 4665 ms, echo - 3. Twenty-seven patients have been enrolled in the study. The tissue contrast coefficients on FLAIR and DIR images have been compared. It has been shown that the contrast coefficient of normal brain structures and brain lesions on the DIR images in regard to the white matter are significantly higher than on the FLAIR images. Results of the study revealed that the dynamics of MR symptoms of intracerebral hematoma is faster on the DIR images compared to the FLAIR ones. This finding can be used for detection of intracerebral hematoma in difficult clinical cases.
