Clinical value of 18F-fluorodeoxyglucose PET-CT in patients with small- and medium-size vessel vasculitis, such as Wegener’s granulomatosis

Objectives Early diagnosis of active Wegener’s granulomatosis, a small- and medium-size blood vessel vasculitis, is crucial in preventing a rapid fatal disease progression. Routine diagnostic tools, such as serum inflammatory markers and plasma antineutrophil cytoplasmic antibodies (ANCA), may often produce inconclusive results. 18F-fluorodeoxyglucose PET-CT is commonly used to identify active inflammatory lesions. However, no cohort studies are reported so far in Wegener’s granulomatosis. This study evaluates the diagnostic value of PET-CT in patients with relapse of Wegener’s granulomatosis.

Methods PET-CT scans were made between December 2006 and October 2011 in 19 patients with biopsy-proven Wegener’s granulomatosis during a period of suspected relapsing disease. CRP, as an inflammatory marker, and ANCA levels were determined at the time of scanning.

Results PET-CT identified foci of active inflammation in all cases, including patients without CRP increase and with inconclusive ANCA levels (13/18). Common PET-positive sites were the nasopharynx (12/19) and the lungs (11/19). Corresponding tissue biopsies confirmed the diagnosis of active Wegener's granulomatosis in all these sites. Additional PET-positive sites were found in the larynx (10/19), bone marrow (10/19), aorta (7/19), and thyroid gland (5/19), showing a multiorgan involvement of the disease in the majority of patients (17/19).

Conclusions PET-CT is able to accurately depict active sites of Wegener’s granulomatosis, including in patients in whom other diagnostic markers have been inconclusive. Multiorgan involvement is often seen on PET-CT in patients with relapsing disease. Overall, functional PET-imaging is a sensitive tool to establish disease distribution and guide diagnostic biopsies in Wegener’s granulomatosis