Utility of brain parenchyma density measurement and computed tomography perfusion imaging in predicting brain death

Purpose: To assess the utility of brain parenchyma density measurement on unenhanced computed tomography (CT) in predicting brain death (BD), in order to evaluate the added value of CT perfusion (CTP). Material and methods: A total of 77 patients who were clinically diagnosed as BD and had both CT angiography (CTA) and CTP imaging in the same session were retrospectively reviewed. On unenhanced phase of CTA, density measurement was performed from 23 regions of interests (ROIs) which were located in the following areas: level of basal ganglia (caudate nucleus, putamen, corpus callosum, posterior limb of internal capsule), level of brainstem, greywhite matters on levels of centrum semiovale (CS), high convexity (HC), and cerebellum. CTP images were evaluated qualitatively and independently. Grey matter (GM), white matter (WM), density, and GM/WM density ratio of BD patients were compared with control subjects. Results: Comparing with the normal control group, the GM and WM density at each level and GM/WM density ratio of CS, HC, and cerebellum level were significantly lower in brain-dead patients (p = 0.019 for HC-WM, p < 0.001 for other areas). Using ROC analysis, the highest value of area under curve (AUC) for the GM/WM density ratio was found at the HC level (AUC = 0.907). The sensitivity of the GM/WM density ratio at the HC level was found to be 90% when the cut-off value of 1.25 was identified. Evaluating the GM/WM density ratio together with the CTP results increased the sensitivity further to 98%. Conclusions: The GM/WM density ratio at the HC level on unenhanced CT may be a useful finding to predict BD. Also, the addition of CTP increases the sensitivity of this method

E2/M1 multipole mixing ratios of transitions in erbium isotopes

Erbium isotopes (Z = 64) lie in the transitional region that occurs at the middle of the range of deformed nuclei. ?-ray E2/M1 mixing ratios for selected transitions in 166-168Er are calculated in the proton-neutron interacting boson approximation(IBA-2). The results obtained for 166-168Er are reasonably in good agreement with the previous experimental and teoretical values

A correspondence between IBA-I and IBA-II model and electromagnetic transitions of some erbium isotopes

Since the lowest levels are symmetric under the interchange of neutrons and protons from calculations in the interacting boson approximation IBA-2 model, IBA-1 model space, in which neutron and proton degrees of freedom are not distinguished can be considered as a subspace of the IBA-2 model space. Using the microscopic background of the IBA-2 model, a correspondence can be established between IBA-1 and IBA-2 model space. Since the space of the IBA-1 model can be regarded as a subspace of the IBA-2 model there is a unique way to "Project" the operators of the IBA-2 model onto those of IBA-1. This projection can be carried out by using the F-spin formalism. In the IBA-2, the lowest states are indeed fully symmetric, the calculations with the help of this projection, we explore the energy levels and the electric quadrupole transition probabilities B(E2;Ii ? If) and ?-ray E2/M1 mixing ratios for selected transitions of 166-168Er. Owing to admixtures of non-fully-symmetric states in IBA-2, we renormalized the parameters (?) and (?).This is the first time we show that this projection can be applied to some heavier isotopes and the results obtained for 166-168Er isotopes are reasonably in good agreement with the previous experimental values. © Association for Scientific Research

A correspondence between IBA-1 and IBA-2 models and electromagnetic transitions in the decay of some erbium isotopes

WOS: 000232142300003The interacting boson approximation IBA-1 model space, in which neutron and proton degrees of freedom are not distinguished, can be considered as a subspace of the IBA-2 model space. Using the microscopic background of the IBA-2 model, a correspondence can be established between IBA-1 and IBA-2 model space. Since the space of the IBA-1 model can be regarded as a subspace of the IBA-2 model there is a unique way to 'Project' the operators of the IBA-2 model onto those of IBA-1. This projection can be carried out using the F-spin formalism. In the IBA-2 model, the lowest states are indeed fully symmetric, and using the calculations with the help of this projection, we explore the energy levels and the electric quadrupole transition probabilities B(E2-, I-i -> I-f) and gamma-ray E2/M1 mixing ratios for selected transitions of Er-161,Er-161,Er-166,Er-168,Er-170. Owing to admixtures of non-fully-symmetric states in IBA-2, we renormalized the parameters (epsilon) and (kappa). This is the first time we show that this projection can be applied to some heavier isotopes and the results obtained for Er-162,Er-164,Er-166,Er-168,Er-170 isotopes are reasonably in good agreement with the previous experimental values

The investigation of the E2/M1 multipole mixing ratios and deformation parameters of electromagnetic transitions in decay of 156Gd

The δ(E2/M1) multipole mixing ratios and deformation parameters of electromagnetic transitions in decay of 156Gd nucleus were studied. The rotation-vibration model (RTV) containing different deformations for protons and neutrons was also discussed. It was observed that the calculated and the experimental values are in good agreement

The investigation of the E2/M1 multipole mixing ratios and deformation parameters of electromagnetic transitions in decay of 156Gd

The ?(E2/M1) multipole mixing ratios and deformation parameters of electromagnetic transitions in decay of 156Gd nucleus were studied. The rotation-vibration model (RTV) containing different deformations for protons and neutrons was also discussed. It was observed that the calculated and the experimental values are in good agreement

Investigation of A ? 100 mass region up to exotic with interacting boson model

CPAN-Ingenio 2010;University of Seville;University of Huelva;International University of Andalucia;Spanish Ministry of Science and Education2009 La Rabida International Scientific Meeting on Nuclear Physics: "Basic Concepts in Nuclear Physics: Theory, Experiments and Applications" -- 4 July 2009 through 10 July 2009 -- La Rabida --Even-even nuclei in the A ? 100 mass region are investigated within the framework of the interacting boson model-1 (IBM-1). The parametrization established on the basis of known elements is then used to predict properties of the unknown. This paper includes the predicted energy spectra and the potential energy surface obtained from the IBM-1 hamiltonian in the classical limit. © 2010 American Institute of Physics

Investigation of A similar to 100 mass region up to exotic with interacting boson model

Rabida International Scientific Meeting on Nuclear Physics -- JUL 04-10, 2009 -- Int Univ Andalucia, La Rabida, SPAINWOS: 000283268100021Even-even nuclei in the A similar to 100 mass region are investigated within the framework of the interacting boson model-1 (IBM-1). The parametrization established on the basis of known elements is then used to predict properties of the unknown. This paper includes the predicted energy spectra and the potential energy surface obtained from the IBM-1 hamiltonian in the classical limit.CPAN Ingenio 2010, Univ Seville, Univ Huela, Int Univ Andalucia, Spanish Minist Sci Educ, Junta Andalucia, European Phys So

An IBM(2) investigation of some properties of 100Ru^{100}Ru nuclei

In this study, energy values, B(E2) values and quadrupole moment of {100}Ru isotope at the onset of the deformed region were investigated by using the Interacting Boson Model (IBM-2). The results were compared with the experimental and theoretical values and it is determined that they are in good agreemen