Tilt-optimized non-saturated excitation (TONE) technique is a special pulse technique for 3D TOF MRA scanning setups that reduces the saturation effect of blood flow within the 3D volume, thus facilitating the display of the outflow segment vessels within the 3D volume. Principle: When 3D TOF MRA scanning, the tissues within the 3D volume must be repeatedly excited by radiofrequency in order to collect blood flow signals. When encoding and collecting the blood vessels in the inflow section of the 3D volume, there is constantly unexcited blood flow outside the volume, so there is no obvious saturation effect on the blood flow, and the signal intensity is higher; while when encoding and collecting the outflow blood vessels in the volume, the blood flow in these areas has been repeatedly excited in the previous section, so there is an obvious saturation effect, and the signal intensity is higher. , and thus there is an obvious saturation effect and signal intensity is significantly weaker. If the deflection angle of the radiofrequency pulse remains unchanged during the acquisition of the entire 3D volume, the blood flow signal gradually decreases from the inflow section to the outflow section, which is not conducive to the display of the blood vessels in the outflow section of the volume. If a pulse with a smaller deflection angle is used to stimulate the blood flow in the inflow segment, the blood flow signal there will be slightly reduced, and such a pulse can reduce the saturation of the blood flow; when part of the saturated blood flow enters the outflow segment, a pulse with a larger deflection angle is used to stimulate the acquisition, and the acquired blood flow signal will be increased. This is partly due to the fact that the blood flow at this location had previously received a smaller pulse angle, thus reducing the saturation effect, and partly because the larger deflection angle used for the acquisition of the outflow section produces a relatively higher signal. By designing the pulses with different deflection angles in this way, the blood flow signals in the inflow and outflow segments of the 3D volume are relatively close to each other, which is especially helpful for the display of blood vessels in the outflow segment. Characteristics: ① The blood flow signals of the inflow section and outflow section in 3D volume are closer to each other; ② It is favorable for the display of blood vessels in the outflow section. Disadvantages: ① 3D volume of the background static tissue signal suppression degree varies, inflow section due to the use of smaller deflection angle excitation, the background due to insufficient suppression and high signal, the outflow section because of the use of a larger deflection angle, the background suppression of the better; ② the use of multi-layer block 3D acquisition, the black band artifacts between the layer block is more pronounced, so more overlap between the layer block needs to be set. Clinical applications and parameter settings: ① thicker single-layer block 3D volume scanning is most suitable for the use of TONE technology; ② multi-layer block acquisition, if the single-layer block thickness is thicker, you can consider the use of TONE; ③ multi-layer block acquisition, if the single-layer block thickness is thinner, there is no need to use the TONE technology; ④ volume of the target blood flow is slower, you can consider the use of TONE; parameters need to be set: ① the direction of blood flow, which will directly affect the effect of TONE technology. will directly affect the effect of TONE technology, such as carotid artery MRA should be set to the direction of blood flow from bottom to top. ② deflection angle, including the starting deflection angle, average deflection angle and maximum deflection angle. In GE, the TONE technique is called ramp pulse technique. after selecting Ramp pulse and blood flow direction in the User CVs interface, you only need to set the flip angle in the main interface, and the system defaults that the flip angle is 2/3 of the average deflection angle, and the maximum deflection angle is set to 4/3 of the average deflection angle.