Atherosclerosis 215 (2011) 82–89 Contents lists available at ScienceDirect Atherosclerosis journal homepage: www.elsevier.com/locate/atherosclerosis A new non-invasive method for detection of local inflammation in atherosclerotic plaques: Experimental application of microwave radiometry K. Toutouzas a,∗ , H. Grassos a , A. Synetos a , M. Drakopoulou a , E. Tsiamis a , C. Moldovan a , G. Agrogiannis b , E. Patsouris b , E. Siores c , C. Stefanadis a a First Department of Cardiology, Hippokration Hospital, Athens, Greece b Department of Pathology, Athens Medical School, Athens, Greece c Centre for Materials Research & Innovation, University of Bolton, United Kingdom article info Article history: Received 27 September 2010 Received in revised form 9 December 2010 Accepted 14 December 2010 Available online 23 December 2010 Keywords: Atherosclerosis Inflammation Diagnosis Vascular biology 1. Introduction Inflammation is implicated in the progression and the instability of atheromatic plaques [1–9]. Previous studies have demonstrated that local inflammatory activation is correlated with the temper- ature of the atheromatic plaques [1,2,5,10–12,8]. For the in vivo assessment of plaque inflammatory activation intravascular ther- mography (IVT) has been applied with dedicated intravascular catheters [2,8,10,12,13,14]. Indeed, IVT is an invasive method, which provides additional diagnostic and prognostic information in the identification of the high-risk atheromatic plaques in patients with coronary artery disease [3,5,9,10,13]. Although IVT has diagnostic and prognostic implications, there are several limitations of current technology limiting its clinical use [13,15,16]. The invasive approach of the method excludes the appli- cation of IVT in primary prevention. Moreover, as there are several technical shortcomings of the available intravascular catheters, a prospective study with distinct endpoints cannot be performed. Thus, the evaluation of the diagnostic and prognostic implications of IVT is infeasible with the current technology. ∗ Corresponding author at: 26 Karaoli and Dimitriou str. Holargos, 15562, Athens, Greece. Tel.: +30 210 6510860. E-mail address: ktoutouz@otenet.gr (K. Toutouzas). Therefore the validation of a new non-invasive method that can identify the inflammatory activation in atheromatic plaques with similar accuracy as IVT, could be an alternative, simple method for the detection of the functional characteristics of the vulnerable atheromatic plaques. Microwave radiometry (MR) is a diagnostic method that provides accurate measurement of the temperature of tissues. MR measures natural electromagnetic radiation from a patient’s internal tissue at microwave frequencies, based on the principle that the intensity of the radiation is proportional to the temperature of tissue [17–28]. It has been applied in oncology for the detection of breast and thyroid cancers, and for monitoring of the treatment of benign tumors [20,25,27–35]. The aim of the present study was to investigate whether 1) microwave radiometry can be safely applied for the non-invasive measurement of arterial wall temperature, and 2) the temperature measurements obtained by MR are correlated with the measure- ments of intravascular thermography, and the local inflammatory activation recognized by histology. 2. Methods 2.1. Animals Twenty four New Zealand White rabbits (weighing 3.8 ± 0.5 kg) were used in this study. Twelve rabbits were randomly assigned 0021-9150/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.atherosclerosis.2010.12.019