Comparison of 99mTc-annexin A5 with 18F-FDG for the detection of atherosclerosis in ApoE−/− mice

• DOI: 10.1007/s00259-007-0433-2
• Publication Date: 2007-04-18T13:33:27Z
• Authors: Yan Zhao; Yuji Kuge; Songji Zhao; Koichi Morita; Masayuki Inubushi; H. William Strauss; Francis G. Blanke...; Nagara Tamaki
• Keywords: Mice, Knockout; Reproducibility of Results; Organotechnetium Compounds; Atherosclerosis; Sensitivity and Specificity; Disease Models, Animal; Mice; 03 medical and health sciences; Apolipoproteins E; 0302 clinical medicine; Fluorodeoxyglucose F18; Animals; Annexin A5; Radiopharmaceuticals; Radionuclide Imaging

(99m)Tc-annexin A5, a marker of ongoing apoptosis, and (18)F-FDG, a marker of the increased metabolism of inflammatory cells, are supposed to be useful in the detection of metabolically active atheroma. This study reports a comparison of the intralesional distribution of these tracers in relation to lesion development in ApoE-/- mice.Male ApoE-/- mice (n = 12-14/group) were maintained on a Western-type diet after the age of 5 weeks. At 25 weeks, (99m)Tc-annexin A5 or (18)F-FDG was injected and the aortas were harvested for autoradiography (ARG) and Oil Red O staining. Regional radioactivity accumulation was compared in relation to the Oil Red O staining score (ranging from 0 to 3, a semiquantitative parameter for evaluating lesion development).Both (99m)Tc-annexin A5 and (18)F-FDG showed preferential uptake into atherosclerotic lesions, with higher uptake levels for (18)F-FDG (mean, 56.07 %IDxkg/m(2)) than for (99m)Tc-annexin A5 (mean, 10.38 %IDxkg/m(2)). The regional uptake levels of each tracer correlated with the Oil Red O staining score (r = 0.65, p < 0.05 for (99m)Tc-annexin A5; r = 0.56, p < 0.05 for (18)F-FDG). The uptake ratios of advanced lesions (score >0.5) to early lesions (score <0.5) were significantly higher for (99m)Tc-annexin A5 than for (18)F-FDG (f = 4.73, p = 0.03).Both (99m)Tc-annexin A5 and (18)F-FDG accumulate in atherosclerotic lesions and correlate with the severity of each lesion. The higher absolute uptake levels of (18)F-FDG may be advantageous for lesion detection, whereas the preferential uptake of (99m)Tc-annexin A5 in advanced lesions may be a useful indicator of late-stage lesions or vulnerable plaque transformation.