Quantitative MRI

Heart function through quantitative MRI—it is possible to obtain quantitative dynamic information on cardiac output, wall thickness, and even work efficiency, beat-by-beat throughout a simulated dive-recovery sequence. These studies already indicate that flow from the heart is continuous through systole and diastole (Thornton et al., 1997a,b), unlike the situation in humans and other terres-... 

Hoptman MJ, Volavka J, Czobor P, Gerig G, Chakos M, et al. 2006. Aggression and quantitative MRI measures of caudate in chronic schizophrenia and schizoaffective disorder. J Neuropsychiatry Clin Neurosci 18 509-515. 

Hoptman MJ, Volavka J, Weiss EM, Czobor P, Szeszko PR, et al. 2005. Quantitative MRI measures of orbitofrontal cortex in patients with chronic schizophrenia or schizoaffective disorder. Psychiatry Res Neuroimaging 140 133-145. 

Obtaining parametric maps necessarily requires estimating the vector of the parameter 0 from K-noised samples. The general theory of estimation59,60 provides solutions that can be applied in the domain of quantitative MRI. In practice, the ML approach is the most commonly used, because it concerns the estimation of non-random parameters, unlike the Bayesian approach, which is mostly applied to segment the images.61 The LS approaches defined by... 

Gale SD, Hopkins RO, Weaver LK, et al MRI, quantitative MRI, SPECT, and neuropsychological findings following carbon monoxide poisoning. Brain Inj 13 229-243, 1999... 

MR spectroscopic results were frequently expressed in terms of peak ratios however, this resulted in doubt about whether one metabolite is elevated or another decreased. Absolute concentration values can eliminate such problems this is especially important when metabolite changes are studied in disease process. The advantage of quantitating MRI data by using water signal in vivo is that the water signal and metabolite signals are obtained under the same conditions. 

Quantitative MRI is possible by calculating the real T1 and T2 figures from the T1 and T2 weighted acquisitions, using the Bloch equation of MRI physics. Multi-modal MRI scans can be exploited for tissue classification when different MRI techniques are applied to the same volume, each voxel is measured with a different physical property, and a feature space can be constructed with the physical units along the dimensional axes e.g. in the characterization of tissue types in atherosclerotic lesions with Tl, T2 and proton density weighted acquisitions, fat pixels tend to cluster, as do blood voxels, muscle voxels, calcified voxels, etc., see Figure 9.8. 

Z. Dunbar, R.I. Masel, Quantitative MRI smdy ofwater distribution during operation of a PEM fuel ceU using Teflon flow belds, J. Power Sources 171 (2007) 678-687. 

Rominger MB et al. (2000) Left ventricular heart volume determination with fast MRI in breath holding technique how different are quantitative heart catheter, quantitative MRI and visual echocardiography Fortschr Roentgenstr... 

Diffusion tensor imaging (DTI) and quantitative T-2 MRI were used to characterize ex vivo the white matter damage at 3 and 8 weeks following dorsal column transection (DC Tx) injury at the cervical level C5 of rat spinal cords. " This study demonstrates that quantitative MRI can accurately characterize white matter damage in DC Tx model of injury in rat spinal cord. 

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