Internal medicine

Radiology

Disease

Nuclear medicine

Vasculitis

Giant cell arteritis

Axillary artery

Medicine

Lara D. Veeken

Objectives To compare colour duplex ultrasonography (CDU) findings with axillary 18F-fluorodeoxyglucose (FDG) PET/CT findings and to compare the diagnostic performance of temporal and axillary artery CDU with temporal artery CDU alone. Methods Patients suspected of GCA were retrospectively included. Presence of a halo or occlusion was considered a positive CDU finding. FDG-PET/CT-assessed axillary artery involvement was defined as axillary artery FDG uptake higher than liver uptake. The reference was the clinical diagnosis after 6 months, which was based on symptomatology and additional diagnostic tests, with the exception of CDU. Results Of the 113 included patients, GCA was diagnosed in 41. Twenty-eight out of 41 GCA patients underwent a FDG-PET/CT. FDG-PET-assessed extra-cranial GCA was present in 20/41 patients, of which 13 showed axillary involvement on FDG-PET/CT. An axillary halo was found in eight of these 13 patients. Six out of the 20 patients with FDG-PET-assessed GCA showed no axillary involvement on CDU or FDG-PET/CT. Five of them had single artery involvement on FDG-PET/CT (two aorta; three vertebral artery). One patient had an axillary occlusion on CDU, consistent with FDG-PET/CT results. Overall, sensitivity and specificity of temporal artery CDU was 52% (95% CI: 35, 67) and 93% (95% CI: 84, 97), respectively. Adding axillary artery results improved sensitivity to 71% (95% CI: 55, 84), while specificity did not change. Conclusion Presence of an axillary halo or occlusion on CDU is consistent with axillary artery FDG-PET/CT results, but a negative CDU does not rule out axillary involvement. Adding axillary artery assessment to temporal artery assessment may substantially increase the diagnostic performance of CDU.

Diagnostic value of axillary artery ultrasound in patients with suspected giant cell arteritis