DLS can determine mean size, size distribution, volume distribution, and molecular weight, and polydispersity index (PDI, a measurement of the distribution of particle sizes in a sample) [43],[43],[43].
Light scattered by these particles changes intensity in time based on this motion and that fluctuation can be fit to describe mean size, size distribution, volume distribution, and dispersity index [43] [45].
The cerebellum was chosen as a region with very low specific PIB binding for use as a reference region, and Logan graphical analyses were performed to calculate the mean cortical PIB distribution volume (Logan et al, 1996) for each participant.
Up to now quantitative perfusion MRI studies of the liver have mainly focused on tissue characterisation with Gd contrast, using the hepatic perfusion index (HPI), mean transit time (MTT), distribution volume (DV), total blood flow (Ft), arterial blood flow (Fa) and portal blood flow (Fp) as parameters.
In this study, the mean apparent clearance and apparent distribution volume of the central compartment of ODTac were 4.77 L/h and 87.3 L, respectively.
Perfusion values were obtained by means of measurements of the distribution volume for the radioactive tracer and for the GBCA, and dividing the flow rate by this value.
True perfusion values were obtained by means of measurements of the distribution volume for the radioactive tracer and gadolinium-based contrast agent (GBCA) and dividing the flow rate by this value.
This means that an increased extravascular distribution volume of crystalloids secondary to a shock-induced SIRS response could explain the low efficacy of crystalloids as plasma volume expanders and such a change in the interstitium has been hypothesized to be an important contributor to inflammation-induced oedema formation [20].
However, these maneuvers negatively interact because an accelerating flow profile tends to reduce mean distribution time, as most of tidal volume is delivered late in the breath, reducing the residence time in the alveoli.
