Evaluation of peri-tumoral vessels surrounding colorectal liver metastases after intravenous injection of extruded magnetoliposomes in rats: correlation with 3T MRI and histopathology.
BACKGROUND
Magnetoliposomes have pronounced signal-enhancing effect on T1-weighted (T1w) images of the liver using qualitative analysis which may be benefical for demonstrating peritumoral vasculature.


OBJECTIVE
To correlate peri-tumoral vasculature (ring-enhancement) surrounding colorectal liver metastases after injection of magnetoliposomes using T1-weighted (T1w) imaging with histopathology in a rat model.


METHODS
All experiments were approved by the responsible Animal Care Committee. Three rats injected with CC531 coloncarcinoma cells in the portal vein were imaged at 3T using a small diameter four channel coil. The presence of liver metastases, signal intensity changes within intrahepatic vessels, peri-tumoral vasculature (ring-enhancement) surrounding liver metastases on T1w imaging and histopathology, and the histopathological distribution of iron particles were evaluated. SS SE-EPI and T1w GE sequences were used. Images were evaluated qualitatively and MRI findings were correlated with histopathology.


RESULTS
Fifteen liver metastases were present which were all detected at MRI (mean diameter 2.4 mm (SD 0.8 mm, range 1.5-4.7 mm)). Ring-enhancement surrounding liver metastases at contrast-enhanced T1w GE sequences was present in all liver metastases. Correlation with histopathology showed the corresponding presence of dilated sinusoids filled with iron particles surrounding the liver metastases.


CONCLUSIONS
Blood-pooling of iron oxide particles within magnetoliposomes was demonstrated with increased and hyperintensity of vessels after injection of magnetoliposomes. Qualitatively, ring-enhancement surrounding the liver metastases was seen on T1w imaging and corresponded histopathologically with the presence of iron particles (magnetoliposomes) within the dilated sinusoids surrounding the liver metastases.
Department of Radiology, AZ St.-Jan Brugge-Oostende AV, Bruges, Belgium. kenneth.coenegrachts@azbrugge.be
K
K
Coenegrachts
J
J
van Werven
L
L
ter Beek
Z
Z
Mzallassi
M
M
Bögels
Th
T
van Gulik
I
I
Van Den Berghe
A
A
Nederveen
J
J
Stoker
H
H
Rigauts
S
S
Soenen
M
M
De Cuyper
D000818:Animals; D015179:Colorectal Neoplasms / Q000473:pathology*; D003287:Contrast Media; D003911:Dextrans; D004134:Dimyristoylphosphatidylcholine; D004195:Disease Models, Animal; D005290:Ferric Compounds; D052203:Ferrosoferric Oxide; D007089:Image Enhancement / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D007202:Indicators and Reagents; D008081:Liposomes; D008099:Liver / Q000473:pathology / Q000648:ultrastructure; D008113:Liver Neoplasms / Q000098:blood supply* / Q000473:pathology / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D058185:Magnetite Nanoparticles; D008297:Male; D010714:Phosphatidylethanolamines; D010715:Phosphatidylglycerols; D010865:Pilot Projects; D051381:Rats
D003287:Contrast Media; D003911:Dextrans; D005290:Ferric Compounds; D007202:Indicators and Reagents; D008081:Liposomes; D058185:Magnetite Nanoparticles; D010714:Phosphatidylethanolamines; D010715:Phosphatidylglycerols; C038089:1,2-distearoylphosphatidylethanolamine; C000499:ferric oxide; C002773:dimyristoylphosphatidylglycerol; C065507:ferumoxides; D004134:Dimyristoylphosphatidylcholine; D052203:Ferrosoferric Oxide