Synchrotron Micro-CT Imaging of Fe and Ca in Atherosclerotic Lesions in ApoE-/-/LDL-/- Double Knockout Mice

Ziele: Using synchrotron-based micro-CT and synchrotron-based X-ray fluorescence microscopy, we investigated advanced atherosclerotic lesions in the aortas of apoE-/-/LDL-/- double knockout mice so as to evaluate the relationship between vasa vasorum (VV) neovascularization and the adventitial inflammatory process/consequences. Methode: Aortas from anesthetized male apoE-/-/LDL-/- (n=27) mice were infused in situ with Microfil, harvested and scanned with micro-CT. Results were complemented by a detailed histological plaque classification according to AHA guidelines. The spatial distribution and size of iron deposits throughout the full 3D extent of lesions were detected by micro-CT and identified as such by histology and by X-ray fluorescence microscopy. Ergebnis: Total VV density and adventitial inflammation increased in lesions with intraplaque hemorrhage (type VIb) and fibroatheromas (type Va) (p<0.0001). The spatial location and magnitude of VV density and adventitial inflammation were strongly correlated in advanced atherosclerotic lesions (r=0.91) and identified as an independent correlate to different advanced lesions. Micro-CT demonstrates the distribution of iron and Ca-hydroxyapatite content within the lesion. Using synchrotron micro-CT, a total of 4.96ng iron/(mm³ lesion volume) was detected, this represents 23,400 erythrocytes/(mm³ lesion volume). Schlussfolgerung: Imaging and staging of advanced atherosclerotic lesions is feasible by synchrotron-based micro-CT. These micro-CT based data suggest that arterial wall iron deposits (as an index of past hemorrhage) in advanced, vulnerable plaques may be detectable with suitably calibrated clinical CT.

Korrespondierender Autor: Langheinrich AC

Mayo Clinic, Department of Physiology and Biomedical Engineering, 1216 Second Street SW, 55901 Rochester

E-Mail: [e-mail]

Key words

Atherosclerosis - Micro-CT - Lesion classification