The impact of 18F-FDG PET on the management of patients with suspected large vessel vasculitis
We aimed to assess the impact of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) on the management of patients with suspected large vessel vasculitis.
An international expert panel determined diagnoses and clinical management in patients with suspected large vessel vasculitis, with and without the results of 18F-FDG PET, respectively. The accuracy of the clinical diagnosis and the resulting clinical management with and without the 18F-FDG PET results were compared using logistic regression models.
The analysis included 30 patients referred to a tertiary care centre with large vessel vasculitis and 31 controls. 18F-FDG PET had an overall sensitivity of 73.3% [95% confidence interval (CI) 54.1–87.7%], a specificity of 83.9% (95% CI 66.3–94.5%), a positive predictive value of 81.5% (95% CI 61.9–93.7%) and a negative predictive value of 76.5% (95% CI 58.8–89.3%). The diagnostic accuracy of 18F-FDG PET was higher in patients not receiving immunosuppressive drugs (93.3 vs 64.5%, p = 0.006). Taken in context with other available diagnostic modalities, the addition of 18F-FDG PET increased the clinical diagnostic accuracy from 54.1 to 70.5% (p = 0.04). The addition of 18F-FDG PET increased the number of indicated biopsies from 22 of 61 patients (36.1%) to 25 of 61 patients (41.0%) and changed the treatment recommendation in 8 of 30 patients (26.7%) not receiving immunosuppressive medication and in 7 of 31 patients (22.6%) receiving immunosuppressive medication.
18F-FDG PET is a sensitive and specific imaging tool for large vessel vasculitis, especially when performed in patients not receiving immunosuppressive drugs. It increases the overall diagnostic accuracy and has an impact on the clinical management in a significant proportion of patients.
KeywordsPositron emission tomography Fluorodeoxyglucose Giant cell arteritis Takayasu’s arteritis Immunosuppressive drugs
The authors declare that they have no conflict of interest. Martin A. Walter gratefully acknowledges the support of the Swiss National Science Foundation. Matthias Briel and Heike Raatz are supported by santésuisse and the Gottfried and Julia Bangerter-Rhyner Foundation. Sergio Prieto-González and Maria C. Cid are supported by Ministerio de Ciencia e Innovacion (SAF 08/04328 and SAF 11/30073).