Distinguishing Takayasu Arteritis and Giant Cell Arteritis Based on Large-Vessel Involvement Patterns

Area of Science:

• Vascular Inflammation
• Rheumatology
• Diagnostic Imaging

Background:

• Takayasu arteritis (TAK) and extracranial large-vessel (LV) giant cell arteritis (GCA) present overlapping clinical and imaging features.
• Accurate differentiation between TAK and GCA is crucial for appropriate patient management and treatment strategies.
• Identifying distinct LV involvement patterns is essential for improving diagnostic accuracy.

Purpose of the Study:

• To identify specific large-vessel (LV) involvement patterns that can reliably differentiate Takayasu arteritis (TAK) from giant cell arteritis (GCA).
• To evaluate the diagnostic accuracy of identified LV involvement patterns using computed tomography (CT) and positron emission tomography/CT (PET/CT).

Main Methods:

• Retrospective cohort study of 181 patients diagnosed with TAK (n=175) or GCA (n=6).
• Assessment of LV involvement patterns via CT and/or ¹⁸F-fluorodeoxyglucose PET/CT at diagnosis.
• Multivariable logistic regression and receiver operating characteristic (ROC) analysis to determine discriminatory accuracy (Area Under the Curve - AUC).

Main Results:

• Specific arteries like the right subclavian artery, aortic arch, descending aorta, and abdominal aorta were less frequently involved in TAK compared to GCA.
• Hata classification type V and cluster 5 showed lower prevalence in TAK.
• A combination model involving right subclavian artery and aortic arch involvement demonstrated the highest diagnostic accuracy (AUC=0.925).

Conclusions:

• Distinct large-vessel (LV) involvement patterns, particularly involving the aortic arch and right subclavian artery, can accurately differentiate Takayasu arteritis (TAK) from giant cell arteritis (GCA).
• The combined assessment of aortic arch and right subclavian artery involvement offers a highly accurate method for distinguishing between these two vasculitic conditions.