In-vivo MR imaging of lipoprotein distribution and metabolism using spio-labeled lipoproteins at 3T

TRL-NS is a potent MR contrast agent with comparable properties to TRL. Dynamic in-vivo MR measurements after application of TRL-NS showed a two phase SNR change with a rapid exponential SNR decrease in order of vena cava, aorta, portal vein followed by a protracted SNR recovery in all vessels. Liver and BAT showed an exponential SNR decline (rΔ0394;SNR
_liver
= -0.60 ±0.14 (p<;0.01); rΔSNR
_BAT
= -0.74±0.13 (p<;0.01)) indicating high metabolism, that was confirmed with radioactive measurements. Skeletal muscle (rΔSNR= -0.08±0.18), myocardium (rΔSNR= -0.10±0.15) and WAT (rΔSNR= -0.05±0.11) showed a non-significant decline trend in contrast to significant uptake measured by y-counting. Brain showed no significant SNR changes in correlation to radioisotope counting. Corresponding to MR imaging histology and electron microscopy confirmed a predominantly accumulation of TRL-NS in liver and brown adipose tissue.