What is the best imaging test for Takayasu's arteritis?

The best imaging test for Takayasu's arteritis is aortic angiography. This condition is a large vessel vasculitis that primarily affects the aorta and its major branches, leading to stenosis and occlusions. Aortic angiography provides clear visualization of the arterial abnormalities, such as narrowing or blockage in major blood vessels.

While CT scans are also useful in assessing vascular involvement and can provide detailed cross-sectional images of the arteries, they might not offer as comprehensive information about the functionality of the flow and any lesions compared to angiography. Ultrasound can be used to assess superficial arteries, but it is limited in its ability to evaluate the thoracic aorta and larger vessels. Plain X-rays typically do not provide sufficient detail about vascular anatomy or abnormalities related to this condition.

Overall, angiography remains the gold standard given its ability to directly visualize the vascular structure and assess flow, making it the preferred choice in diagnosing and evaluating the extent of Takayasu's arteritis.