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A systematic review finds the technique highly sensitive and specific in diagnosing giant cell arteritis, especially useful when biopsy results are equivocal.
Soussan M, Nicolas P, Schramm C, et al. Management of Large-Vessel Vasculitis With FDG-PET: A Systematic Literature Review and Meta-Analysis.Medicine. 2015;94(14)e622. doi: 10.1097/MD.0000000000000622
18F-fluorodeoxyglucose positron emission tomography (FDG-PET) has high sensitivity and specificity for diagnosing large-vessel inflammation in giant cell arteritis (GCA). This could be useful where GCA is still suspected after a negative temporal artery biopsy.
The sensitivity and specificity for Takayasu arteritis (TA) is almost as good.
This was the result of a systematic review of 21 studies with 413 patients and 299 controls. Inflammatory cells such as macrophages or granulation tissue avidly take up FDG. FDG-PET showed FDG vascular uptake in 70% of patients and 7%ofcontrols. Only vascular uptake equal to or higher than the liver uptake was significantly different between GCA or TA patients and controls.
For GCA, the sensitivity was 90% and the specificity was 98%. For TA, the sensitivity was 87% and specificity was 73%.