18F-FDG PET reveals unique features of large vessel inflammation in patients with Takayasu's arteritis.
OBJECTIVE
The object of this study was to assess whether18F-fluorodeoxyglucose PET/CT (FDG PET/CT) provides novel information in patients with Takayasu's arteritis (TA) in addition to that provided by current activity assessment, to analyse the effects of possible confounders, such as arterial grafts, and to verify whether PET/CT could be informative in lesions <4 mm thick.


METHODS
We studied 30 patients with TA, evaluated from October 2010 to April 2014 by both PET/CT and magnetic resonance imaging (MRI). All arterial lesions were evaluated by PET both qualitatively (positive/negative) and semiquantitatively (maximum standardized uptake value, SUVmax), and the thickness of lesions in the MRI field of view was evaluated. In a per-patient analysis, the relationships between the PET data and acute-phase reactants and NIH criteria for active TA were evaluated. In a per-lesion analysis, the relationships between the PET features of each lesion and MRI morphological data were evaluated. The effects of the presence of arterial grafts were also evaluated.


RESULTS
Increased FDG uptake was seen in 16 of 30 patients (53%) and in 46 of 177 vascular lesions (26%). Significant periprosthetic FDG uptake was seen in 6 of 7 patients (86%) with previous vascular surgery and in 10 of 11 of grafts (91%). Graft-associated uptake influenced the PET results in three patients (10%) and the SUVmaxvalues in five patients (17%). Of 39 lesions with significant FDG uptake, 15 (38%) were <4 mm thick. Lesion thickness was correlated with lesion SUVmaxin FDG-avid lesions only. FDG arterial uptake was not associated with systemic inflammation or NIH criteria.


CONCLUSIONS
PET/CT reveals unique and fundamental features of arterial involvement in TA. PET/CT may be useful in the assessment of local inflammatory and vascular remodelling events independent of systemic inflammation during follow-up, even in lesions in which the arterial wall is <4 mm. The presence of arterial grafts is a potential confounder. Prospective studies are required to correlate PET findings with relevant clinical outcomes.
Unit of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy.
Elena
E
Incerti
Vita-Salute San Raffaele University, Milan, Italy.|Unit of Internal Medicine and Clinical Immunology, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Enrico
E
Tombetti
Unit of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy.
Federico
F
Fallanca
Unit of Internal Medicine and Clinical Immunology, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Elena M
EM
Baldissera
Unit of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy.
Pierpaolo
P
Alongi
Vita-Salute San Raffaele University, Milan, Italy.
Elisabetta
E
Tombolini
Vita-Salute San Raffaele University, Milan, Italy.|Unit of Internal Medicine and Clinical Immunology, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Silvia
S
Sartorelli
Vita-Salute San Raffaele University, Milan, Italy.|Unit of Internal Medicine and Clinical Immunology, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Maria Grazia
MG
Sabbadini
Department of Radiology, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Maurizio
M
Papa
Vita-Salute San Raffaele University, Milan, Italy.|Department of Radiology, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Francesco
F
De Cobelli
Vascular Science and Rheumatology, Imperial College London and Imperial College Healthcare NHS Trust, London, UK.
Justin C
JC
Mason
Unit of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy.
Luigi
L
Gianolli
Vita-Salute San Raffaele University, Milan, Italy.|Unit of Internal Medicine and Clinical Immunology, IRCCS San Raffaele Scientific Institute, Milan, Italy.
Angelo A
AA
Manfredi
Unit of Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Via Olgettina 60, 20132, Milan, Italy. picchio.maria@hsr.it.
Maria
M
Picchio
D000328:Adult; D000368:Aged; D001158:Arteries / Q000000981:diagnostic imaging* / Q000378:metabolism; D001692:Biological Transport; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography; D013625:Takayasu Arteritis / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology; D055815:Young Adult
D015415:Biomarkers; D019788:Fluorodeoxyglucose F18
Arterial grafts; Disease activity; FDG PET/CT; MRI; Takayasu’s arteritis; Vasculitis