Investigation on the optimal position for the quantification of hepatic perfusion by use of dynamic contrast-enhanced computed tomography in rats

Abstract

Our purpose in this study was to investigate the optimal position for the quantification of hepatic perfusion by using a dual-input, single-compartment model and dynamic contrast-enhanced computed tomography (DCE-CT) in rats. The DCE-CT studies were performed with the animals in the supine and prone position, with an interval of 1 day, on six male Sprague-Dawley rats. The distance between the inferior vena cava (IVC) and portal vein was calculated. The arterial hepatic blood flow (AHBF) and portal hepatic blood flow (PHBF) were also estimated by use of time-density curves (TDCs) in the aorta, portal vein, and liver. The distance between the IVC and portal vein in the supine position (3.68 +/- 0.22 mm) was significantly greater than that in the prone position (2.56 +/- 0.19 mm). The estimated AHBF (102.1 +/- 8.9 ml/100 ml/min) and PHBF values (114.8 +/- 19.7 ml/100 ml/min) in the prone position were significantly overestimated and underestimated, respectively, as compared to those in the supine position (76.1 +/- 4.2 ml/100 ml/min for AHBF and 235.1 +/- 17.3 ml/100 ml/min for PHBF). We concluded that the supine position was more appropriate than the prone position for the quantification of hepatic perfusion by use of a dual-input, single-compartment model and DCE-CT in rats, because the TDC in the portal vein is affected less by the TDC in the IVC in the supine position than in the prone position.

Mechanism of hard-nanomaterial clearance by the liver

“…In arteries and veins, nanomaterials travel at velocities of 10–100 cm/s 18–20 but slow down to 200–800 μm/s when they enter a liver sinusoid 21,22 . We hypothesized that the reduced velocity promotes preferential nanomaterial accumulation within the sinusoid.…”

Biodistribution of therapeutic extracellular vesicles

“…In addition, the microarchitecture of the liver and spleen is designed in a way that enhances the interaction of nanoparticles with the MPS system to enhance the clearance [121][122][123] [Figure 3]. As the nanoparticles move from the peripheral circulation to the liver, the velocity of nanomaterial is reduced from 10-100 cm/sec to 0.2-0.8 cm/sec [124][125][126] . This reduction in blood flow by 100-1,000 folds allows nanoparticles to interact with the MPS system in the liver more efficiently.…”

Drug Monitoring by Optically Pumped Atomic Magnetometer

“…It has been proven that body sites with lower blood velocities will have nanomaterial accumulation preferentially [28]. In the liver sinusoid, blood flow at velocities of 200 to 800 µm/s, is significantly slower than in the systemic circulation (10-100 cm/s) [29]- [33]. Drug particles are inclined to aggregate in the liver via transcytosis, and then go into the gastrointestinal tract, eventual were eliminated in feces [34].…”