Figure 2: (a) Ultrasound measurement of the brachial artery. 13 MHz linear transducer is fixed along brachial artery with a special probe holder (MP-PH0001, Aloka Co., Ltd., Tokyo, Japan). (b) Display of CDI. Left: image of the vessel image and position of the artery tracking gate. Right: changes in vessel diameter, Doppler flow, and flow velocity, as determined by an automated edge detection device and computer analysis software (e-Tracking system; Aloka Co., Ltd., Tokyo, Japan).