YY/T 0593-2022Transcranial doppler ultrasound system (English PDF)

3.1 Transcranial doppler ultrasound system

An equipment that utilizes the principle of ultrasound doppler to measure the blood flow in intracranial blood vessels through the skull.

NOTE: by configuring the corresponding probe, it can also be used for blood flow measurement in the extracranial neck and peripheral blood vessels.

3.2 Nominal acoustic working frequency

Ultrasonic working frequency published by the designer or manufacturer.

NOTE: the unit is megahertz (MHz).

3.3 Sample volume

When pulsed doppler is used to measure the blood flow velocity, the sampling area of the measurement site.

NOTE 1: the unit is millimeters (mm).

NOTE 2: the width of the sample volume of the TCD instrument cannot be adjusted, and the length of the sample volume can only be adjusted by controlling the duration of the pulse wave.

5.1 Ultrasonic Working Frequency

The deviation between the ultrasonic working frequency and the nominal ultrasonic frequency published by the manufacturer shall be not greater than ± 10%.

50 Hz, 100 Hz, 200 Hz and 400 Hz;

d) Spectrum analysis function;

e) Spectrum resolution setting;

f) Range gating setting;

g) Sampling area setting;

h) Receive gain adjustment;

i) Baseline movement;

j) Scale setting;

k) Parameter measurement: in the frozen state of the atlas, velocity, acceleration, vascular pulsation index (PI) and vascular resistance index (RI) can be measured;

l) The range gating parameters of each channel of the dual-channel TCD instrument can be independently adjusted.

5.8 Appearance and Structure

5.8.1 The outer casing of the TCD instrument shall have no obvious mechanical damage, rust and other defects, and the texts and logos on the panel shall be clearly visible.

5.8.2 The plastic parts of the TCD instrument shall be free from blistering, cracking, deformation and overflow of filling material.

5.8.3 The operation and adjustment mechanism of the TCD instrument shall be flexible and reliable, and the fasteners shall not be loose.

5.9 Safety

The TCD instrument shall comply with the requirements of GB 9706.1 and GB 9706.237.

5.10 Environmental Test

The environmental test requirements of the TCD instrument shall comply with the manufacturer's stipulations in accordance with the climatic environment test group I and the mechanical environment test group II in GB/T 14710. The test time, recovery time and inspection items shall comply with the supplementary stipulations in Table 2. The special requirements and methods of environmental test can be implemented in accordance with the principles and stipulations of YY/T 1420.

It is recommended use blood-mimicking phantoms and string-type test pieces. The requirements for blood-mimicking phantoms can take YY/T 0458 as a reference; the requirements for string-type test pieces can take YY/T 0705 as a reference.

6.2 Ultrasonic Working Frequency

In accordance with the method specified in YY/T 1142, carry out the test, which shall comply with the requirements of 5.1.

6.3 Flow Velocity Measurement Range and Error

In accordance with the interval of the flow velocity measurement range, different test methods can be adopted. When the set value of the measured flow velocity is within the range of Table 1, adopt the blood-mimicking phantoms or string-type test pieces for the test. When the set value of the measured flow velocity exceeds the measuring range of the blood-mimicking phantoms or string-type test pieces, the method in Appendix A can be used for the test.

When blood-mimicking phantoms or string-type test pieces are used for the test, follow the instructions for use of the blood-mimicking phantoms or string-type test pieces. The settings of the TCD instrument under test are as follows:

a) Blood vessel selection, filtering, sound power and receive gain are adjusted to the optimal position;

b) The working distance and sample volume are set in accordance with the stipulations of Table 1;

c) It is recommended to select 30°, 45° or 60° for the included angle between the doppler sound beam axis (generally, the axis of the probe handle) and the target movement direction. When calculating the displayed flow velocity error, in addition to the actual angle mentioned above, it shall also be considered that the doppler angle of the TCD instrument is set to 0°;

d) When testing the flow velocity measurement range, the flow velocity of the phantoms is respectively set at the maximum value and minimum value of the flow velocity measurement range of the TCD instrument under test; when the flow velocity measurement range of the TCD instrument exceeds the measuring range of the blood-mimicking phantoms or string-type test pieces, the method in Appendix A can be used for the test;

e) When testing the flow velocity measurement error, the flow velocity of the phantoms is respectively set at 1/3 and 2/3 of the flow velocity measurement range of the TCD instrument under test.

The test results shall comply with the requirements of 5.2 and 5.3.

6.4 Working Distance

Adopt the blood-mimicking phantoms or string-type test pieces, at the nominal maximum working distance and minimum working distance, use a TCD instrument to detect the target.

Check whether the displayed frequency spectrum is normal, which shall comply with the requirements of 5.4.

6.5 Range Gating Error

The sample volume of the TCD instrument is recommended to be set to 4 mm and 20 mm, and other statuses are set to the optimum. Adopt the ultrasonically blood-mimicking doppler phantom. It is recommended that the distance between the tested point of the blood-mimicking phantom and the probe be set at 50 mm. Set the range gating of the TCD instrument also to 50 mm and use the TCD instrument to detect the tested point of the blood-mimicking phantom. At this moment, the TCD instrument shall have obvious doppler spectrum signals. Increase or decrease the set value of the range gating, find the point with the strongest signal to read the range gating, or find the position with the same signal strength in the upward and downward directions. Record the range gating set values in both directions and take the average value. The absolute value of the difference from the actual value (50 mm) is used as the range gating error of the two sample volumes of 4 mm and 20 mm, and the most unfavorable value shall comply with the requirements of 5.5.

A TCD instrument with M mode functions can use the M mode display window to accurately find the test signal. By selecting the strongest point of the signal band on the M mode display window, the range gating of this signal can be read.

6.6 Ultrasonic Output Power Adjustment

Successively adapt probes with different operating frequencies and operating modes to the TCD instrument, respectively observe their spectrum signal strengths when the output power is set to the relatively small and large values. There shall be corresponding changes, which shall comply with the requirements of 5.6.

6.7 Working Status and Function Settings

Operate in accordance with the stipulations of the instruction manual and verify by checking the screen display and working status, which shall comply with the requirements of 5.7.

6.8 Appearance and Structure

Conduct visual inspection and operation inspection, which shall comply with the requirements of 5.8.

6.9 Safety

Conduct the test in accordance with the stipulations of GB 9706.1 and GB 9706.237, which shall comply with the requirements of 5.9. […]

6.10 Environmental Test