Author + information
- Received December 8, 2009
- Accepted February 9, 2010
- Published online August 17, 2010.
- Francesca Pugliese, MD, PhD⁎,
- Oliver Gaemperli, MD⁎,
- Anne R. Kinderlerer, MD†,
- Frederic Lamare, PhD⁎,
- Joseph Shalhoub, BSc‡,
- Alun Huw Davies, MA, DM‡,
- Ornella E. Rimoldi, MD⁎,
- Justin C. Mason, PhD† and
- Paolo G. Camici, MD⁎,§,⁎ ()
- ↵⁎Reprint requests and correspondence:
Prof. Paolo G. Camici, MRC Clinical Sciences Centre, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, United Kingdom
Objectives We sought to investigate whether positron emission tomography/computed tomography (CT) angiography using [11C]-PK11195, a selective ligand for peripheral benzodiazepine receptors expressed in activated macrophages, can be used to image vascular inflammation.
Background Activated macrophages and T lymphocytes are fundamental elements in the pathogenesis of large-vessel vasculitides.
Methods Fifteen patients (age 52 ± 16 years) with systemic inflammatory disorders (6 consecutive symptomatic patients with clinical suspicion of active vasculitis and 9 asymptomatic control patients) underwent positron emission tomography with [11C]-PK11195 and CT angiography. [11C]-PK11195 uptake was measured by calculating target-to-background ratios of activity normalized to venous blood.
Results Coregistration of positron emission tomography with contrast-enhanced CT angiography facilitated localization of [11C]-PK11195 arterial wall uptake. Visual analysis revealed focal [11C]-PK11195 uptake in the arterial wall of all 6 symptomatic patients, but in none of the asymptomatic controls. Although serum inflammatory biomarkers (C-reactive protein, erythrocyte sedimentation rate, white cell count) did not differ significantly between the 2 groups, symptomatic patients had increased [11C]-PK11195 vascular uptake (target-to-background ratio 2.41 ± 1.59 vs. 0.98 ± 0.10; p = 0.001).
Conclusions By binding to activated macrophages in the vessel wall, [11C]-PK11195 enables noninvasive imaging of vascular inflammation. Alternative longer-lived radioligands for probing peripheral benzodiazepine receptors are being tested for wider clinical applications.
Dr. Gaemperli was financially supported by a Swiss National Science Foundation research grant. Dr. Mason was supported by the National Institute for Health Research Biomedical Research Centre funding scheme. All other authors report that they have no relationships to disclose. Drs. Pugliese, Gaemperli, Mason, and Camici contributed equally to this work.
- Received December 8, 2009.
- Accepted February 9, 2010.
- American College of Cardiology Foundation