Takayasu and temporal arteritis.

Takayasu and temporal arteritis are primary large-vessel vasculitides. Ultrasound directly depicts the inflamed vessel wall, which is homogenously and circumferentially thickened. Furthermore, stenoses and occlusions occur. Ultrasound almost completely depicts the whole length of the common superficial temporal arteries, including the frontal and parietal ramus. Inflammation is often segmental. This may lead to a false-negative histology. The wall swelling is hypoechoic in acute temporal arteritis. It disappears within 2-3 weeks with corticosteroid treatment. Sonographers should use 8-15 MHz linear probes. The pulse repetition frequency should be about 2.5 kHz. Color box steering and beam steering should be maximal. It is essential that the color covers the artery lumen exactly. Sensitivities and specificities with regard to clinical diagnosis and histology are high. Large-vessel giant cell arteritis is a subset of temporal arteritis, with involvement of the subclavian, axillary, and proximal brachial arteries. The wall swelling resolves much slower with treatment. In Takayasu arteritis ultrasound is a valuable diagnostic tool to investigate particularly the common carotid, subclavian, and vertebral arteries. The echogenicity of the arterial wall thickening is, in general, higher than in giant cell arteritis, as the nature of Takayasu arteritis is more chronic, with less wall edema.