Imaging of vascular inflammation with [11C]-PK11195 and positron emission tomography/computed tomography angiography

Francesca Pugliese, Oliver Gaemperli, Anne R. Kinderlerer, Frederic Lamare, Joseph Shalhoub, Alun Huw Davies, Ornella E. Rimoldi, Justin C. Mason, Paolo G. Camici
Journal of the American College of Cardiology. 2010-08-01; 56(8): 653-661
DOI: 10.1016/j.jacc.2010.02.063

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1. J Am Coll Cardiol. 2010 Aug 17;56(8):653-61. doi: 10.1016/j.jacc.2010.02.063.

Imaging of vascular inflammation with [11C]-PK11195 and positron emission
tomography/computed tomography angiography.

Pugliese F(1), Gaemperli O, Kinderlerer AR, Lamare F, Shalhoub J, Davies AH,
Rimoldi OE, Mason JC, Camici PG.

Author information:
(1)Medical Research Council Clinical Sciences Centre and National Heart and Lung
Institute, Imperial College, and Hammersmith Hospital, London, 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.

Copyright (c) 2010 American College of Cardiology Foundation. Published by
Elsevier Inc. All rights reserved.

DOI: 10.1016/j.jacc.2010.02.063
PMID: 20705222 [Indexed for MEDLINE]

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