Atherosclerosis as a potential pitfall in the diagnosis of giant cell arteritis

Area of Science:

• Vascular Ultrasound
• Arterial Imaging
• Rheumatology

Background:

• Giant Cell Arteritis (GCA) diagnosis relies on clinical signs and imaging.
• The ultrasound halo sign in temporal arteries (TAs) is a key indicator for GCA.
• Atherosclerosis can affect IMT and potentially mimic GCA signs.

Purpose of the Study:

• To investigate the correlation between intima-media thickness (IMT) in arteriosclerotic disease and TA IMT.
• To determine if increased IMT in arteriosclerosis can mimic the ultrasound GCA halo sign.

Main Methods:

• Carotid and TA IMT measurements using standardized ultrasound software and a 22 MHz probe.
• Inclusion of consecutive patients aged 50+ with high vascular risk, excluding GCA symptoms.
• Correlation analysis between carotid IMT and TA IMT.

Main Results:

• Significant correlation found between carotid IMT and TA IMT.
• Carotid IMT >0.9 mm was associated with TA IMT >0.3 mm.
• Only one patient exceeded the proposed TA IMT threshold.

Conclusions:

• Arteriosclerotic disease, particularly with carotid IMT >0.9 mm, elevates TA IMT.
• Elevated TA IMT may mimic the halo sign, leading to potential misdiagnosis of GCA.
• A TA IMT cut-off of >0.34 mm in at least two branches is proposed to minimize false positives in GCA diagnosis.