ORIGINAL ARTICLE Feasibility of [18F]-RGD for ex vivo imaging of atherosclerosis in detection of avb3 integrin expression Reza Golestani, MD, PhD, a,b Leila Mirfeizi, PhD, a Clark J. Zeebregts, MD, PhD, c Johanna Westra, MD, PhD, d Hans J. de Haas, BS, a Andor W. J. M. Glaudemans, MD, a Michel Koole, PhD, a Gert Luurtsema, PhD, a Rene ´ A. Tio, MD, PhD, e Rudi A. J. O. Dierckx, MD, PhD, a,f Hendrikus H. Boersma, PharmD, PhD, a,g Philip H. Elsinga, PhD, a and Riemer H. J. A. Slart, MD, PhD a,h a Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands b Cardiovascular Medicine Section, Department of Internal Medicine, Yale University, New Haven, CT c Division of Vascular Surgery, Department of Surgery, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands d Department of Clinical Immunology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands e Department of Cardiology, Thorax Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands f Department of Nuclear Medicine, Ghent University Hospital, Ghent, Belgium g Department of Clinical and Hospital Pharmacy, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands h Faculty of Science and Technology, Biomedical Photonic Imaging, University of Twente, Enschede, The Netherlands Received Sep 2, 2014; accepted Dec 15, 2014 doi:10.1007/s12350-014-0061-8 Background. Inflammation and angiogenesis play an important role in atherosclerotic plaque rupture. Therefore, molecular imaging of these processes could be used for determination of rupture-prone atherosclerotic plaques. avb3 integrin is involved in the process of angiogenesis. Targeted imaging of avb3 integrin has been shown to be possible in previous studies on tumor models, using radiolabeled arginine-glycine-aspartate (RGD). Our aim was to investigate feasi- bility of ex vivo detection of avb3 integrin in carotid endarterectomy (CEA) specimens. Methods and Results. Nineteen CEA specimens were incubated in 5 MBq [18F]-RGD-K5 for 1 hour followed by 1 hour emission microPET scan. The results were quantified in 4 mm wide segments as percent incubation dose per gram (%Inc/g). Segmental-to-total ratio was calculated and presence of avb3 integrin and endothelial cells in each segment was confirmed by immuno- histochemical staining for CD31 and avb3 integrin, respectively. [18F]-RGD-K5 uptake was heterogeneously distributed across CEA specimens and was localized within the vessel wall. Significant correlations were observed between segmental-to-total ratio with avb3 integrin staining score (r 5 0.58, P 5 .038) and CD31 staining score (q 5 0.67, P < .002). Conclusion. This study showed the feasibility of integrin imaging by determination of avb3 integrin expression in human atherosclerotic plaques. (J Nucl Cardiol 2015) Reza Golestani and Leila Mirfeizi contributed equally to this study. Reprint requests: Reza Golestani, MD, PhD, Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, P.O. Box 30001, 9700 RB Groningen, The Netherlands; reza.golestani@ yale.edu 1071-3581/$34.00 Copyright Ó 2015 American Society of Nuclear Cardiology.