Specific features to differentiate Giant cell arteritis aortitis from aortic atheroma using FDG-PET/CT

AbstractAortic wall 18F-fluorodeoxyglucose (FDG)-uptake does not allow differentiation of aortitis from atheroma, which is problematic in clinical practice for diagnosing large vessel vasculitis giant-cell arteritis (GCA) in elderly patients. The purpose of this study was to compare the FDG uptake characteristics of GCA aortitis and aortic atheroma using positron emission tomography/FDG computed tomography (FDG-PET/CT). This study compared FDG aortic uptake between patients with GCA aortitis and patients with aortic atheroma; previously defined by contrast enhanced CT. Visual grading according to standardized FDG-PET/CT interpretation criteria and semi-quantitative analyses (maximum standardized uptake value (SUVmax), delta SUV (∆SUV), target to background ratios (TBR)) of FDG aortic uptake were conducted. The aorta was divided into 5 segments for analysis. 29 GCA aortitis and 66 aortic atheroma patients were included. A grade 3 FDG uptake of the aortic wall was identified for 23 (79.3%) GCA aortitis patients and none in the atheroma patient group (p < 0.0001); grade 2 FDG uptake was as common in both populations. Of the 29 aortitis patients, FDG uptake of all 5 aortic segments was positive for 21 of them (72.4%, p < 0.0001). FDG uptake of the supra-aortic trunk was identified for 24 aortitis (82.8%) and no atheromatous cases (p < 0.0001). All semi-quantitative analyses of FDG aortic wall uptake (SUVmax, ∆SUV and TBRs) were significantly higher in the aortitis group. ∆SUV was the feature with the largest differential between aortitis and aortic atheroma. In this study, GCA aortitis could be distinguished from an aortic atheroma by the presence of an aortic wall FDG uptake grade 3, an FDG uptake of the 5 aortic segments, and FDG uptake of the peripheral arteries.

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Large-Vessel Vasculitis: Interobserver Agreement and Diagnostic Accuracy of18F-FDG-PET/CT

BioMed Research International ◽

10.1155/2015/914692 ◽

2015 ◽

Vol 2015 ◽

pp. 1-8 ◽

Cited By ~ 23

Author(s):

K. D. F. Lensen ◽

E. F. I. Comans ◽

A. E. Voskuyl ◽

C. J. van der Laken ◽

E. Brouwer ◽

...

Keyword(s):

Diagnostic Accuracy ◽

Giant Cell Arteritis ◽

Giant Cell ◽

Fdg Pet ◽

Interobserver Agreement ◽

External Validation ◽

Vascular Wall ◽

Fdg Uptake ◽

Pet Ct ◽

Fdg Pet Ct

Introduction.18F-FDG-PET visualises inflammation. Both atherosclerosis and giant cell arteritis cause vascular inflammation, but distinguishing the two may be difficult. The goal of this study was to assess interobserver agreement and diagnostic accuracy of18F-FDG-PET for the detection of large artery involvement in giant cell arteritis (GCA).Methods. 3118F-FDG-PET/CT scans were selected from 2 databases. Four observers assessed vascular wall18F-FDG uptake, initially without and subsequently with predefined observer criteria (i.e., vascular wall18F-FDG uptake compared to liver or femoral artery18F-FDG uptake). External validation was performed by two additional observers. Sensitivity and specificity of18F-FDG-PET were determined by comparing scan results to a consensus diagnosis.Results. The highest interobserver agreement (kappa: 0.96 in initial study and 0.79 in external validation) was observed when vascular wall18F-FDG uptake higher than liver uptake was used as a diagnostic criterion, although agreement was also good without predefined criteria (kappa: 0.68 and 0.85). Sensitivity and specificity were comparable for these methods. The criterion of vascular wall18F-FDG uptake equal to liver18F-FDG uptake had low specificity.Conclusion. Standardization of image assessment for vascular wall18F-FDG uptake promotes observer agreement, enables comparative studies, and does not appear to result in loss of diagnostic accuracy compared to nonstandardized assessment.

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