Weak or absent popliteal artery pulsation is a sign of vasculitis. Examination of vasculitis is of great significance for treatment, and a comprehensive and accurate examination can bring the disease to a definitive diagnosis and effective treatment as soon as possible. But what kind of examination is needed to confirm the diagnosis of vasculitis? Ancillary examinations The diagnosis of thrombo-occlusive vasculitis is usually made on the basis of medical history and physical examination. The following ancillary tests can help further clarify the site, extent, nature, and degree of arterial occlusion and the establishment of collateral circulation. Skin temperature measurement Under certain room temperature (15-25℃), a decrease in limb temperature of more than 2℃ compared with the corresponding part of the opposite side indicates insufficient blood supply to that side of the limb. Infrared thermogram Infrared thermography detects the infrared radiation from the surface of the limb and converts it into a thermogram. At the same time, the temperature of each sampling point can be expressed numerically. Infrared thermograms of the limb in thromboembolic vasculitis may show a darker glow and abnormal “cold areas” in the ischemic areas of the affected limb. Segmental manometry and stress testing Segmental manometry provides information on the systolic arterial pressure of each segment of the limb. Thrombo-occlusive vasculitis often manifests as a decrease in blood pressure below the popliteal or brachial artery of the affected limb. If the lesion is limited to the lower extremity, the ankle/brachial index (normal value ≥1) reflects the severity of ischemia in the affected extremity. If segmental manometry is normal, stress tests, such as exercise tests and reactive congestion tests, may be used. Ankle pressure decreases significantly after stress tests in patients with early thrombo-occlusive vasculitis, and ankle pressure recovery time is prolonged. Pulse wave tracing The arterial waveform of each segment of the limb can be traced by using Doppler flow velocimetry and various volumetric tracers. In thrombo-occlusive vasculitis, the distal arterial waveform of the affected limb often appears as a unidirectional wave with low amplitude and blunt peaks. In severe lesions, the arterial waveform is linear. Arteriography Arteriography can clarify the site, extent, nature, and degree of arterial occlusion, as well as the establishment of branch circulation in the affected limb. Arteriography in thromboembolic vasculitis typically shows segmental occlusion of small and medium-sized arteries, while normal arteries with smooth walls can be seen between the diseased arteries. In addition, many small collateral vessels are often seen. Because arteriography is an invasive test, it can cause arterial spasm and endothelial damage, aggravating limb ischemia, and is generally not used as a routine test for this disease.