PET/MRI in large-vessel vasculitis: clinical value for diagnosis and assessment of disease activity

Charlotte Laurent,Amir Adedjouma,Arsène Mekinian,Laure Ricard,Michael Soussan,Irene Buvat,Olivier Fain

doi:10.1038/s41598-019-48709-w

Abstract

Diagnosis of large vessel vasculitis (LVV) and evaluation of its inflammatory activity can be challenging. Our aim was to investigate the value of hybrid positron-emission tomography/magnetic resonance imaging (PET/MRI) in LVV. All consecutive patients with LVV from the Department of Internal Medicine who underwent PET/MRI were included. Three PET/MRI patterns were defined: (i) “inflammatory,” with positive PET (>liver uptake) and abnormal MRI (stenosis and/or wall thickening); (ii) “fibrous”, negative PET (≤liver uptake) and abnormal MRI; and (iii) “normal”. Thirteen patients (10 female; median age: 67-years [range: 23–87]) underwent 18 PET/MRI scans. PET/MRI was performed at diagnosis (n = 4), at relapse (n = 7), or during remission (n = 7). Among the 18 scans, eight (44%) showed an inflammatory pattern and three (17%) a fibrous pattern; the other seven were normal. The distribution of the three patterns did not differ between patients with Takayasu arteritis (TA, n = 10 scans) and those with giant cell arteritis (GCA, n = 8 scans). PET/MRI findings were normal in 2/10 (20%) TA scans vs. 5/8 (62%) GCA scans (p = 0.3). Median SUVmax was 4.7 [2.1–8.6] vs. 2 [1.8–2.6] in patients with active disease vs. remission, respectively (p = 0.003). PET/MRI is a new hybrid imaging modality allowing comprehensive and multimodal analysis of vascular wall inflammation and the vascular lumen. This technique offers promising perspectives for the diagnosis and monitoring of LVV.

Highlights

Diagnosis of large vessel vasculitis (LVV) and evaluation of its inflammatory activity can be challenging
C-reactive protein (CRP) level and number of patients on steroids at 6 months were similar with all positron-emission tomography/magnetic resonance imaging (PET/MRI) patterns, as was the rate of remission (Table 1)
The inflammatory pattern, defined as both abnormal positron-emission tomography (PET) and MRI, was highly associated with disease activity, in Takayasu’s arteritis (TA). This pattern was found in all scans from patients with active TA disease compared to only 50% of scans from patient with active giant cell arteritis (GCA)

Summary

Introduction

Diagnosis of large vessel vasculitis (LVV) and evaluation of its inflammatory activity can be challenging. PET/MRI is a new hybrid imaging modality allowing comprehensive and multimodal analysis of vascular wall inflammation and the vascular lumen This technique offers promising perspectives for the diagnosis and monitoring of LVV. Several studies have shown good sensitivity of fluorine-18-fluorodeoxyglucose (FDG)-PET/computed tomography (CT) for the diagnosis of arterial involvement in LVV, with a sensitivity around 89.5% for GCA and 87% for TA2–6. In TA, a recent study in twenty-six patients who underwent graft surgery have shown that significant 18F- FDG uptake that is confined to arterial graft sites does not reflect clinically relevant disease activity or progression[9]. The results demonstrate that T1W VIBE MRI of the aorta detects vessel wall inflammation in a comparable number of patients with LVV in relation to 18F-FDG PET14. The aim of this study was to describe the PET/MRI findings in patients with LVV and to determine their relation with clinical outcome

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