In recent years, high-frequency ultrasound, due to its higher resolution, can clearly display the superficial vascular structure and blood flow, and can detect vascular lesions early, providing a new non-invasive tool for clinical observation of the structure and blood flow of the extremity artery. The purpose of this multi-center study is to establish the normal value of high frequency ultrasound for the structure and blood flow of the extremity arteries of Chinese Han adults, and to explore the influencing factors, so as to provide a quantitative reference for the early diagnosis, degree evaluation and curative effect observation of the structure and blood flow of the extremities.

The extremity artery is the peripheral blood vessel of the whole body, and it is often involved early in the diseases that are easy to damage the small vessels, such as atherosclerosis and connective tissue diseases. Early lower limb atherosclerosis mainly occurs in the dorsal foot artery, which is commonly seen in people with diabetes and long-term smoking. Connective tissue diseases such as systemic sclerosis and systemic lupus erythematosus also mainly involve small blood vessels, and vascular lesions may appear earlier than those of other specific organs such as heart and lung. Because of its shallow location, the extremity artery can be better used as a screening site for vascular diseases, and it is the window for early reaction of vascular diseases.However, the early stage of extremity artery disease is easy to be ignored, and patients often have pain and numbness of the affected limb. When the disease is severe, it can lead to ulcer not healing, and even limb gangrene and amputation, which greatly affects the quality of life and brings huge troubles and economic pressure to the patients. Therefore, early diagnosis of extremity arterial lesions is of great significance for early diagnosis of microvascular injury diseases such as atherosclerosis and connective tissue diseases, reducing the incidence of complications, and reducing the rate of amputation and mortality.

Ultrasound is a non-invasive imaging technique widely used in clinic. In recent years, with the development of ultrasound technology, the frequency of ultrasonic probes has been increasing. Because of its higher resolution, high-frequency ultrasound can clearly display the superficial vascular structure and blood flow, detect vascular lesions early, and accurately quantify the degree of stenosis, providing a new and beneficial tool for clinical observation of the structure and blood flow of the extremity artery. The purpose of this multi-center clinical study was to establish the normal value of high frequency ultrasound for the structure and blood flow of the extremities of Chinese Han adults, and to explore its influencing factors, so as to provide a quantitative reference for the early diagnosis, degree evaluation and curative effect observation of the structure and blood flow of the extremities.

Inclusion Criteria:

1. Han nationality;
2. Ages 18-79;
3. Normal blood pressure (139-90/89-60mmHg);
4. Body mass index < 30 kg/m2;
5. Blood routine, fasting blood glucose, blood lipid, liver and kidney function, electrocardiogram were normal;
6. No history of cyanosis of hands and feet, cold stimulation without discomfort, no Raynaud phenomenon has occurred in all parts of the body;
7. No cardiovascular disease, diabetes, rheumatic connective tissue disease, serious liver and kidney dysfunction;
8. No history of drug use affecting cardiovascular system.

Exclusion Criteria:

1. Patients with hypertension, diabetes, hyperthyroidism, arrhythmia and other diseases;
2. Patients with systemic lupus erythematosus, polymyositis, rheumatoid arthritis and other connective tissue diseases;
3. A history of related blood diseases;
4. Have taken vasoconstrictor drugs in the past 1 month;
5. Gangrene of fingers and toes or history of trauma or surgery;
6. Have a history of handicraft, hammering, digging and other related work;
7. Have a long history of smoking and drinking;
8. Peripheral vascular disease, arterial occlusion can not detect blood flow signal;
9. Unable to cooperate with the examiner.

Chinese healthy Han adults