Author + information
- Received February 26, 2018
- Revision received May 4, 2018
- Accepted June 14, 2018
- Published online December 3, 2018.
- Gabriele Ironi, MDa,b,∗∗ (, )
- Enrico Tombetti, MDb,c,d,∗,
- Angela Napolitano, MDa,b,
- Marta Campolongo, RTa,
- Federico Fallanca, MDe,
- Elena Incerti, MSce,
- Maria Picchio, MDb,e,
- Lorenzo Dagna, MDb,c,
- Angelo A. Manfredi, MDb,c,d,
- Luigi Gianolli, MDe,
- Alessandro Del Maschio, MDa,b and
- Francesco De Cobelli, MDa,b
- aDepartment of Radiology and Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy
- bVita-Salute San Raffaele University, Milan, Italy
- cUnit of Immunology, Rheumatology, Allergy and Rare Diseases (UnIRAR), IRCCS San Raffaele Scientific Institute, Milan, Italy
- dDivision of Immunology, Transplantations and Infectious Diseases, IRCCS San Raffaele Scientific Institute, Milan, Italy
- eDepartment of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy
- ↵∗Address for correspondence:
Dr. Gabriele Ironi, Department of Radiology and Experimental Imaging Center, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Via Olgettina 60, 20132 Milan, Italy.
- diffusion-weighted imaging (DWI)
- giant cell arteritis (GCA)
- magnetic resonance imaging (MRI)
Giant cell arteritis (GCA) is a granulomatous large-vessel vasculitis. The wall of inflamed arteries contains an abundant infiltrate of lymphocytes and macrophages and undergoes substantial remodeling, with hyperplasia of the intimal layer, luminal occlusion and potentially aneurysm formation and dissection (Figure 1). Vascular inflammation is typically transmural and affects primarily 2 arterial districts: cephalic arteries and/or the aorta and its main branches (1). Diffusion-weighted imaging (DWI) is a functional magnetic resonance imaging (MRI) technique that investigates the movement of water molecules within tissues; water molecules have a restricted free motion in tissues with increased cellularity, and this generates a hyperintense signal on high b-value (e.g., b = 600) DWI images. Given the strong inflammatory infiltrate within the arterial wall of a patient with active GCA (2,3), we hypothesize that diffusion-weighted magnetic resonance imaging (DWI-MRI) may reveal the increased cellularity in the inflamed vessel wall. For the first time, we applied DWI-MRI to evaluate aortic wall inflammation in a group of 8 patients with GCA with known involvement of the aorta and its main branches. In parallel, short tau inversion recovery (STIR) sequence was performed to study arterial wall edema. Disease activity and arterial involvement were defined by an expert rheumatologist, based on clinical and laboratory data, and a fluorine-18 (18F) labeled fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) study. Accordingly, 2 patients presented overtly active GCA, 3 patients smoldering disease, and 3 inactive disease. Five healthy volunteers served as controls for MRI studies. DWI findings were in accordance with activity status and FDG-PET/CT in all 8 subjects; DWI clearly and homogenously depicted the arterial wall of patients with active GCA even in cases of minor wall thickening (Figure 2). In patients with ongoing therapy with smoldering disease, aortic wall was still viewable in DWI images, but its hyperintensity was less than that of patients with active disease (Figure 3). In contrast, in patients with inactive disease (Figure 4) and in healthy controls (Figure 5), the aortic wall did not show any hyperintensity at DWI, and thus it was not visible in this sequence.
In conclusion, in accordance with FDG-PET/CT, DWI-MRI can characterize the arterial wall involved by GCA and reveal ongoing inflammation. This might be relevant to define large-vessel involvement in GCA and might be helpful in the assessment of disease activity.
↵∗ Drs. Ironi and Tombetti equally contributed to this work.
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received February 26, 2018.
- Revision received May 4, 2018.
- Accepted June 14, 2018.
- 2018 American College of Cardiology Foundation
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