The diagnostic accuracy of temporal artery ultrasound and temporal artery biopsy in giant cell arteritis –A single centre Australian experience over 10 years

The diagnostic accuracy of temporal artery ultrasound and temporal artery biopsy in giant cell arteritis –A single centre Australian experience over 10 years

Reviewer: Kylie Elmore | ASA SIG: Vascular

Authors: He J, Williamson L, Ng B, Wang J, Manolios N, Angelides S, Farlow D and Wong Reviewer: Kylie Elmore | ASA SIG: Vascular

Why the study was performed

Temporal artery biopsy (TAB) remains the gold standard in Australia for the diagnosis of giant cell arteritis (GCA). Obstacles to performing TAB include the increasing cost of healthcare, the need for hospital admission, potential perioperative complications and logistical issues for patients in areas that don’t have access to rheumatological services. This study aimed to assess the diagnostic accuracy of temporal artery ultrasound and therefore its potential use as a viable alternative.

How the study was performed

A single-centre retrospective study was performed over a 10-year period between 2011 and 2020. Patients with clinical symptoms of GCA and who had an ultrasound performed by a qualified sonographer were identified.

The ultrasound was considered positive for GCA based on the sonographic findings of:

• ‘halo sign’ or hypoechoic wall thickening of the temporal artery

• ‘compression sign’ or the inability to ablate the vessel lumen with probe pressure due to wall inflammation.

In addition to this, sonographers provided information on temporal artery patency, stenosis and flow velocity. Corresponding medical records were reviewed to retrieve biopsy findings.

What the study found

Ultrasound examinations were performed on 63 patients over the 10-year period and the data proposes that 20 per cent of ultrasounds performed were considered positive. Of those patients who had also undergone TAB, the study showed a moderately strong correlation between ultrasound and TAB results. Of the 32 negative temporal artery ultrasound examinations, only 4 patients had a positive TAB. Of the 12 patients who had a positive temporal artery ultrasound, only 2 were negative at TAB. This study found that temporal artery ultrasound had a sensitivity of 71.4% and a specificity of 93.3%. These findings were found to be comparable to international standards.

Relevance to clinical practice

In the hands of an experienced, qualified sonographer, the high specificity of a positive temporal artery ultrasound may reduce the need for TAB. This has the potential to reduce healthcare costs, patient morbidity, delay in diagnosis and logistical issues. Standardised protocols in reporting and performing ultrasounds for GCA as well as improved training for sonographers were identified strategies that could be utilised to further enhance patient outcomes.

“If positive in the setting of a suggestive clinical presentation, a temporal artery ultrasound probably avoids the need for a temporal artery biopsy”