Biopsy vs imaging in the diagnosis of giant cell arteritis. Viewpoint 1: in favour of imaging.

Objectives: Both imaging and temporal artery biopsy (TAB) are utilized to confirm a suspected diagnosis of giant cell arteritis (GCA). What are the advantages of imaging over TAB?

Methods: This article is based on a debate presented at the 21st Vasculitis Meeting, discussing whether imaging or TAB with histology should be the primary diagnostic method for suspected GCA.

Results: A suspected diagnosis of GCA should be confirmed or excluded either through imaging or histology. The author advocates for imaging, particularly US, as the initial diagnostic test, in line with EULAR recommendations. Alternatives to US include MRI, CT, and PET, mostly performed in conjunction with CT. Imaging is non-invasive, reliable, sensitive also to extracranial GCA, and specific. Particularly, US is widely available, cost-effective, and patient-friendly. Rheumatologists can perform it promptly during clinical history taking and examination. The introduction of Fast-Track Clinics providing rapid access to specialist care and US has reduced instances of permanent vision loss. The clinical presentation and imaging findings must be conclusive; otherwise, a second diagnostic test should be conducted. This could be another imaging test, such as PET for suspected extracranial GCA, or TAB for suspected cranial GCA. Importantly, the diagnostic process should not delay the initiation of glucocorticoid treatment in suspected GCA cases.

Conclusion: A suspected diagnosis of GCA should be confirmed or excluded via imaging or TAB. Imaging, particularly US, offers several advantages over TAB as the initial diagnostic test.