At high magnetic fields diagnostic proton MRI of the lung is problematic, because of fast T2* relaxation. The application of superparamagnetic contrast agents and the exploitation of the corresponding T2* effect is inefficient with conventional MRI methods, which limits the early detection of lung diseases. However, a simple theoretical treatment shows that… (More)
(19) F MRI offers high specificity but usually low sensitivity. Here, paramagnetic relaxation enhancement is assessed as a method to improve SNR efficiency in (19) F MRI. Compounds with short relaxation times are used that combine fluorine and a paramagnetic ion within the same molecule. Different molecular designs provide T1 values in the range of 1.4-15… (More)
From a family of 14 individuals, evidence was obtained suggesting linkage between the HL-A haplotypes and the transmission of a 50 percent deficit in the functional activity of the C2 component of complement.
PURPOSE Optogenetic fMRI (ofMRI) is a novel tool in neurophysiology and neuroimaging. The method is prone to light-induced artifacts, two of which were investigated in this study. METHODS ofMRI was performed in rats using two excitatory opsins (ChR2 and C1V1TT ) virally transduced in somatosensory cortex or thalamus. Heat-induced apparent BOLD activation… (More)
The combination of optogenetic control and fMRI readout in the brain is increasingly used to assess neuronal networks and underlying signal processing. However, how exactly optogenetic activation or inhibition reproduces normal physiological input has not been fully unraveled. To assess details of temporal dynamics of the hemodynamic response, temporal… (More)
Encoding of sensory inputs in the cortex is characterized by sparse neuronal network activation. Optogenetic stimulation has previously been combined with fMRI (ofMRI) to probe functional networks. However, for a quantitative optogenetic probing of sensory-driven sparse network activation, the level of similarity between sensory and optogenetic network… (More)
OBJECT The purpose of this study was to investigate the achievable precision of localization of boundaries between extended uniform objects in MRI and to study the effect of zero-filling on reaching it. MATERIALS AND METHODS A theoretical model of an object boundary in the presence of noise was introduced, and the error of localization was derived. The… (More)