DOI: 10.1186/s13550-017-0268-1Pages: 1-9

Characteristics of immunoglobulin G4-related aortitis/periaortitis and periarteritis on fluorodeoxyglucose positron emission tomography/computed tomography co-registered with contrast-enhanced computed tomography

1. Hokkaido University Graduate School of Medicine, Department of Radiation Medicine

2. Hokkaido University Hospital, Department of Diagnostic and Interventional Radiology

3. Hokkaido University Hospital, Department of Nuclear Medicine

4. Hokkaido University Hospital, Department of Surgical Pathology

Correspondence to:
Noriko Oyama-Manabe
Email: norikooyama@med.hokudai.ac.jp

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Abstract

Background

We aimed to assess the positivity, distribution, quantitative degree of vessel inflammation, and clinical characteristics of IgG4-related aortitis/periarteritis and periarteritis (IgG4-aortitis), and to examine the difference in these characteristics between cases with and without IgG4-aortitis, using fluorodeoxyglucose positron-emission tomography/computed tomography (FDG-PET/CT) co-registered with contrast-enhanced CT (CECT).

We retrospectively evaluated 37 patients with IgG4-related disease (IgG4-RD) who underwent both FDG-PET/CT and CECT. The arterial SUVmax and its value normalized to the background venous blood pool (BP)—the target-to-background ratio (TBR) in the entire aorta and the major first branches—were measured. Active vascular inflammation was considered in cases with a higher FDG uptake than BP and a thickened arterial wall (>2 mm).

Results

Fifteen (41%) patients exhibited IgG4-aortitis. Most patients (80%) showed multiple region involvement. The entire aorta, including the major first branches, were involved, typically showing a thickened wall and high FDG uptakes. The most common site was the iliac arteries (35%), followed by the infrarenal abdominal aorta (33%), thoracic aorta (8%), first branches of the thoracic aorta (8%), suprarenal abdominal aorta (6%), and the first branches of the abdominal aorta (5%). The IgG4-aortitis-positive vessel regions were thickened, with an average maximal wall thickness of 6.3 ± 2.9 mm. The SUVmax and TBR values were significantly higher in the IgG4-aortitis-positive regions (median 3.7 [1.6–5.5] and 2.1 [1.4–3.7], respectively) than in the IgG4-aortitis-negative regions (median 2.1 [1.2–3.7] and 1.3 [0.9–2.3], respectively; p < 0.0001). The IgG4-aortitis-positive group patients were older (69.5 ± 6.0 vs. 63.3 ± 12.6 years, respectively) and had a higher male predominance (80 vs. 55%, respectively) than the negative group, although the differences were not significant (p = 0.17 and p = 0.06, respectively).

Conclusions

We investigated the image characteristics of IgG4-aortitis. The entire aorta and major branches can be involved with more than 2-fold higher FDG uptake than the venous background pool, and with wall thickening. The most common involved site is the iliac arteries, followed by the infrarenal abdominal aorta.

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  • Accepted: Feb 18, 2017
  • Online: Feb 27, 2017

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