Non-Invasive Imaging of Vascular Inflammation

Abstract

In large-vessel vasculitides, inflammatory infiltrates may cause thickening of the involved arterial vessel wall leading to progressive stenosis and occlusion. Dilatation, aneurysm formation, and thrombosis may also ensue. Activated macrophages and T lymphocytes are fundamental elements in vascular inflammation. The amount and density of the inflammatory infiltrate is directly linked to local disease activity. Additionally, patients with autoimmune disorders have an increased cardiovascular (CV) risk compared with age-matched healthy individuals as a consequence of accelerated atherosclerosis. Molecular imaging techniques targeting activated macrophages, neovascularization, or increased cellular metabolic activity can represent effective means of non-invasive detection of vascular inflammation. In the present review, novel non-invasive imaging tools that have been successfully tested in humans will be presented. These include contrast-enhanced ultrasonography, which allows detection of neovessels within the wall of inflamed arteries; contrast-enhanced CV magnetic resonance that can detect increased thickness of the arterial wall, usually associated with edema, or mural enhancement using T2 and post-contrast T1-weighted sequences, respectively; and positron emission tomography associated with radio-tracers such as [18F]-fluorodeoxyglucose and the new [11C]-PK11195 in combination with computed tomography angiography to detect activated macrophages within the vessel wall. Imaging techniques are useful in the diagnostic work-up of large- and medium-vessel vasculitides, to monitor disease activity and the response to treatments. Finally, molecular imaging targets can provide new clues about the pathogenesis and evolution of immune-mediated disorders involving arterial vessels.

Vascular ultrasound for monitoring of inflammatory activity in Takayasu arteritis

“…In addition, contrast-enhanced ultrasonography could increase the ability to detect neovascularization (Ammirati et al, 2014;Schinkel et al, 2014;Herlin et al, 2015;Germano et al, 2017a;Germano et al, 2017b).…”

An extended high‐frequency ultrasound protocol for detection of vessel wall inflammation

“…DUS was performed when the acute oedema had disappeared. Another sonographic finding in arteritis is neovascularization in the arterial wall, and future clinical applications of DUS may also include contrast‐enhanced ultrasonography to detect these findings (Ammirati et al ., ).…”

“…DUS was performed when the acute oedema had disappeared. Another sonographic finding in arteritis is neovascularization in the arterial wall, and future clinical applications of DUS may also include contrast-enhanced ultrasonography to detect these findings (Ammirati et al, 2014). The histological picture of GCA is characterized by inflammatory infiltrate with lymphocytes, macrophages and multinucleated giant cells often located at the intima-media junction.…”

“…Evaluation of patients with imaging techniques apart from ultrasound includes computerized tomography (CT) scan, arterial angiography, magnetic resonance imaging (MRI) angiography and positron emission tomography CT scan (PET-CT) (Ammirati et al, 2014). Nevertheless, the resolution is lower with radiological methods compared to DUS (Schmidt, 2014).…”

Dyslipidemia in patients with systemic lupus erythematosus: Association with disease activity and B-type natriuretic peptide levels

“…Patients with SLE have a higher prevalence of subclinical atherosclerosis and a higher risk of CV events compared to the general population (10). The estimated prevalence of CVD in the SLE population is between 6 and 10%, with an annual incidence of 1.3-1.5% (9,11,12).…”