The Grounds of Concrete Logic (Základové konkretné logiky) is often taken to be a work in which Masaryk attempts to outline, in a methodical way, his conception of philosophy as “a real scientific metaphysics”. Nevertheless, we often hear from the Masaryk’s critics, and even from his followers, that the book appears to be no more than a transcription of Comte’s Cours de philosophie positive. Even if the classification of the
sciences was one of the main philosophical and scientific problems with which Masaryk was engaged throughout his life, in the emphasis on concrete sciences, and in the working out of the relations between particular sciences and categories, Masaryk goes beyond Comte. This point is supported, at the same time, by the many critical notes concerning the inadequacy of Comte’s epistemological grounding, which Masaryk links, above all, to a critique of Comte’s phenomenalism. The specific quality and the critical reference of the book for future generations of Czech philosophers consists in its principled status and realist aim. Concrete logic should bring us to the ultimate ontological points of departure – to things themselves. In his prioritising of the need to seek the sense of things, Masaryk belongs to the modern thinkers who showed to Czech philosophy new possibilities and ways of approach to reality in a strictly scientific spirit.
Disruption of the blood-brain barrier (BBB) is a key feature of various brain disorders. To assess its integrity a parametrization of dynamic magnetic resonance imaging (DCE MRI) with a contrast agent (CA) is broadly used. Parametrization can be done quantitatively or semi-quantitatively. Quantitative methods directly describe BBB permeability but exhibit several drawbacks such as high computation demands, reproducibility issues, or low robustness. Semi-quantitative methods are fast to compute, simply mathematically described, and robust, however, they do not describe the status of BBB directly but only as a variation of CA concentration in measured tissue. Our goal was to elucidate differences between five semi-quantitative parameters: maximal intensity (Imax), normalized permeability index (NPI), and difference in DCE values between three timepoints: baseline, 5 min, and 15 min (Δ5-0, Δ15-0, Δ15-5) and two quantitative parameters: transfer constant (Ktrans ) and an extravascular fraction (Ve). For the purpose of comparison, we analyzed DCE data of four patients 12-15 days after the stroke with visible CA enhancement. Calculated parameters showed abnormalities spatially corresponding with the ischemic lesion, however, findings in individual parameters morphometrically differed. Ktrans and Ve were highly correlated. Δ5-0 and Δ15-0 were prominent in regions with rapid CA enhancement and highly correlated with Ktrans . Abnormalities in Δ15-5 and NPI were more homogenous with less variable values, smoother borders, and less detail than Ktrans . Moreover, only Δ15-5 and NPI were able to distinguish vessels from extravascular space. Our comparison provides important knowledge for understanding and interpreting parameters derived from DCE MRI by both quantitative and semi-quantitative methods.