ABSTRACT
The aim of the study was a comparison of 2 novel macromolecular contrast agents, Gadomer-17 and Polylysine-Gd-DTPA, with commercially available Gd-DTPA in determining the quality of tumor microvasculature by dynamic contrast enhanced MRI. Three groups of 5 mice with SA-1 tumors were studied. To each group of animals one contrast agent was administered; i.e. the first group got Gd-DTPA, the second group Gadomer-17 and the third group Polylysine-Gd-DTPA. To perform dynamic contrast enhanced MRI a standard keyhole approach was used by which consecutive signal intensity change due to contrast agent accumulation in the tumor was measured. From the obtained data, tissue permeability surface area product PS and fractional blood volume BV were calculated on a pixel-by-pixel basis. PS and BV values were calculated for each contrast agent. Based on the values, contrast agents were classified according to their performance in characterizing tumor microvasculature. Results of our study suggest that Gadomer-17 and Polylysine-Gd-DTPA are significantly superior to Gd-DTPA in characterizing tumor microvasculature.
Subject(s)
Contrast Media/chemistry , Fibrosarcoma/diagnosis , Gadolinium DTPA , Gadolinium , Magnetic Resonance Imaging/methods , Polylysine/analogs & derivatives , Animals , Blood Volume , Capillary Permeability , Diffusion , Endothelial Cells , Fibrosarcoma/blood supply , Fibrosarcoma/physiopathology , Gadolinium/chemistry , Gadolinium DTPA/chemistry , Mice , Polylysine/chemistryABSTRACT
The subchronic effects of cyanobacterial lyophilizate (CL) containing microcystins on liver were investigated in female New Zealand rabbits. Sterilised CL containing microcystins was injected i.p. Liver toxicity was assessed by histological examination of liver samples. Non-invasive magnetic resonance imaging (MRI) of liver was also performed in order to assess changes in the homogeneity of liver tissue. Subchronical intoxication with microcystins caused morphological changes of liver tissue that were also detected by use of MRI. Histological analysis showed that changes seen on MRI represent liver injury characterised with fatty infiltration and periportal fibrosis. This demonstrates that subchronic exposure to microcystins can lead to liver degeneration, which can easily be detected in vivo by use of MRI.
ABSTRACT
The purpose of this study was to test the capability of contrast enhanced magnetic resonance imaging (MRI) in assessing lesion formation in rat brain after systemic (i.v.) administration of kainate. MRI was performed with T1 -weighted spin echo sequence before and after the administration of kainate and contrast media. Contrast media used were based on paramagnetic gadolinium (III) ion: Gd-DTPA (gadoliniumdiethylene-triaminepentaacetic acid) and prototype agents for blood-pool enhancement Gadomer-17 and polylysine-Gd-DTPA. Enhancement of lesion rims and other brain tissue abnormalities due to kainate with Gd-DTPA, Gadomer-17 and polylysine-Gd-DTPA were observed mainly in the region of hippocampus and in the areas not protected by the blood-brain-barrier (BBB).
