The purpose of this investigation was to 1) evaluate the relative accuracy of the Sokoloff and Patlak tracer kinetic models in estimating glucose metabolic rate (GMR) in the presence and absence of insulin; 2) evaluate the effect of nutritional state on the lumped constant (LC); and 3) compare the kinetics of 2-fluoro-2-deoxy-d-[14C]glucose (FDG) and 2-deoxy-d-[3H]glucose (DG) membrane transpor...

The aim of this study is to evaluate the stride-to-stride fluctuations in walking, to investigate dynamic changes in gait variability, to quantify effects of locomotor neuromuscular system complexity and its manifestation in healthy control and pathological subjects using Poincaré plot (PP) symbolic complexity measures. It is found in the literature that the standard descriptors used with PP, a...

OBJECTIVES Improved brain uptake ratio (IBUR), employing (99m)Tc-ethyl cysteinate dimer ((99m)Tc-ECD), is an automatic non-invasive method for quantitatively measuring regional cerebral blood flow (rCBF). This method was developed by the reconstruction of the theory and linear regression equation, based on rCBF measurement by H2 (15)O positron emission tomography. Clarification of differences i...

We revisit the question of global regularity for the Patlak-Keller-Segel (PKS) chemotaxis model. The classical 2D parabolic-elliptic model blows up for initial mass M > 8π. We consider more realistic scenario which takes into account the flow of the ambient environment induced by harmonic potentials, and thus retain the identical elliptic structure as in the original PKS. Surprisingly, we find ...

Regional cerebral blood flow (rCBF) measurements using a Patlak plot method of 99mTc-ECD were performed in early dementia of Alzheimer type (DAT) with both HDS-R and MMSE of over 20 to investigate initial abnormality and longitudinal changes of rCBF. A fusion technique of MRI and SPECT images was developed for MRI-guided analysis of regions of interest in hippocampal areas and statistical param...

Introduction: The key characteristics of positron emission tomography (PET) are its quantitative capability and its sensitivity, which allow the in vivo imaging of biochemical interactions with small amounts of tracer concentrations. Therefore, accurate quantification is important. However, it can be sensitive to several physical factors. The aim of this investigation is the assessment of the e...