Therefore, the software selleck provided in a colour scale pixel, maps of functional parameters for blood flow (BF), blood volume (BV), and mean transit time (MTT) using the central volume principle [8, 9]. The capillary permeability-surface area product (PS) was calculated according to the following equation: PS = – blood
flow [ln (1- E)], where E is the extraction fraction (the fraction of contrast material that leaks into the extravascular space from the intravascular space) . Contrast-enhanced images were superimposed on the colour map in order to facilitate visual identification of the cryoablated area. BF (in millilitres per 100 g of wet tissue per minute) is OICR-9429 nmr defined as the flow rate of blood through the vascular net in a tissue. BV (in millilitres per 100 g of wet tissue) is the volume of blood within the vascular net of a tissue that was flowing and not stagnant. Mean transit
time (in seconds) corresponds to the average time taken by the blood elements to traverse the vasculature www.selleckchem.com/products/Temsirolimus.html from the arterial end to the venous end. PS (in millilitres per 100 g of wet tissue per minute) is the product of permeability and the total surface area of capillary endothelium in a unit mass of tissue representing the total diffusion flux across all capillaries. The pCT is based on a tracer kinetic analysis in which enhancement of the tissue (HU), sampled during Cytidine deaminase arrival of the contrast agent by cine CT scanning, is
linearly proportional to the concentration of contrast agent in the tissue. Thus, the time-attenuation curves for the regions of interest were analyzed by means of a mathematical deconvolution method that takes advantage from this linear relationship between the iodine concentration and the CT attenuation numbers. In particular, deconvolution method uses arterial input function (AIF) to which compare the curve obtained on parenchimal ROIs so as to correct the effect of bolus dispersion and better reflect the tracer kinetic model, which requires an instantaneous bolus input and tissue time-attenuation curves to calculate the impulse residue function (IRF) which is the time enhancement curve of the tissue due to an idealized instantaneous injection of one unit of tracer. It is characterized by an instantaneous peak to a plateau, as the contrast material enters and remains within the tissue, followed by decays as the contrast material washes out from the tissue. The height of the function gives the tissue blood flow (BF) and the area under the curve determines the relative blood volume (BV) [11–13]. Deconvolution analysis is most widely used in acute cerebrovascular disease in which the blood brain barrier is intact.