Original ArticleQuantitative X-Ray Imaging of Intraplaque Hemorrhage in Aortas of ApoE−/−/LDL−/− Double Knockout MiceLangheinrich, Alexander C. MD*†; Michniewicz, Agata†; Sedding, Daniel G. MD‡; Lai, Barry PhD§; Jorgensen, Steven M. BSEE*; Bohle, Rainer M. MD¶; Ritman, Erik L. MD, PhD*Author Information From the *Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, Minnesota; Departments of †Radiology, and ‡Cardiology, Justus-Liebig University Giessen, Giessen, Germany; §Advanced Photon Source, Argonne National Lab, Argonne, Illinois; and ¶Department of Pathology, Justus-Liebig University Giessen, Giessen, Germany. Received August 16, 2006, and accepted for publication, after revision, December 15, 2006. Supported by grants (Young Investigator Program) from the faculty of human medicine of the Justus-Liebig University Giessen, Germany and NIH grants EB000305 and HL65342 at Mayo Clinic College of Medicine, Rochester, MN. Use of the National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY, was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-ACO2-98CH100886. Use of the Advanced Photon Source, Argonne, IL was supported by the US Department of Energy, Office of Science, Basic Energy Sciences, under Contract No. W-31-109-Eng-38. Reprints: Erik L. Ritman, MD, PhD, Department of Physiology and Biomedical Engineering, Alfred 2-409, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905. E-mail: [email protected]. Investigative Radiology: May 2007 - Volume 42 - Issue 5 - p 263-273 doi: 10.1097/01.rli.0000258085.87952.ea Buy Metrics Abstract Objectives: To determine if hemorrhage into an arterial wall can be detected in CT images by virtue of the iron content. Materials and Methods: Aortas from male apoE−/−/LDL−/− mice (n = 31) were infused in situ with contrast agent, for micro-CT scanning and histology. Roentgen-opacities within the aortic walls were identified by histology and micro-x-ray fluorescence to be iron or calcium. Dual-energy scanning was performed at 2 energy levels using synchrotron-based micro-CT [(2 μm)3 voxels, 16 and 20 keV] and 64-slice CT (0.4 × 0.4 × 0.6 mm voxels, 80 and 120 kVp). Results: Opacities were identified as hemorrhage-related clusters of multiple punctate deposits, containing both Fe (0.48 × 10−12 g/voxel) and Ca (3.18 × 10−2 g/voxel), or as isolated confluent accumulations of exclusively calcium. Subtraction of the dual-energy CT scans discriminated iron from calcium deposits. Conclusion: Detection and quantification of iron deposits in hemorrhaged atherosclerotic lesions is feasible by dual-energy CT imaging. © 2007 Lippincott Williams & Wilkins, Inc.