Pharmacokinetic modeling of phagocytic activity of the liver using superparamagnetic iron oxide nanoparticles in dynamic MR imaging.
The purpose of this study was to determine whether phagocytic activity is measurable by dynamic superparamagnetic iron oxide-enhanced MR imaging. For these experiments on New Zealand White rabbits, which were randomly allocated to normal and silica treated groups, we performed a dynamic MR study and radioisotope study with Tc99m-phytate. In this dynamic MR study, the ratio (Rv) of the distribution volumes of iron oxide (Vm/Ve) could be obtained by applying three- compartment model to the data obtained from the kidney and liver simultaneously. Changes in Rv caused by silica injection and by dosing superparamagnetic iron oxide, AMI-25, were evaluated. In the dynamic MR study using a Beagle dog model the input function could be calculated from data obtained from the hepatic artery and portal vein. Rv's reached maximum values at around 80 minutes after the AMI-25 injection. The Rv of the normal group was 5.06 +/- 1.53 whereas the Rv of the silica treated group was 2.13 +/- 1.20. The results were similar to tissue count data obtained by radioisope study. The Rv value was not dependent on the injected dose of AMI-25. The rate of transport constants (k1, k2, k3) could not be estimated using the 3 compartment model regardless of obtaining the input function. We conclude that Rv may be an quantitative index of decreased phagocytic activity in the liver as determined by dynamic superparamagnetic iron oxide- enhanced MRI.
Na
Jae Boem
JB
Department of Diagnostic Radiology, Yonsei University College of Medicine, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-752, Korea.
Suh
Jin-Suck
JS
Huh
Yong-Min
YM
Kim
Sung-Joon
SJ
Kim
Seung-Hyung
SH
Cha
Seung-Hwan
SH
Lee
Sang-Hoon
SH
D000818:Animals; D003287:Contrast Media; D003911:Dextrans; D004285:Dogs; D052203:Ferrosoferric Oxide; D007501:Iron; D008099:Liver / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D058185:Magnetite Nanoparticles; D008954:Models, Biological; D036103:Nanotechnology; D010087:Oxides; D010316:Particle Size; D010587:Phagocytosis; D011817:Rabbits
D003287:Contrast Media; D003911:Dextrans; D058185:Magnetite Nanoparticles; D010087:Oxides; D007501:Iron; C065507:ferumoxides; D052203:Ferrosoferric Oxide