YY/T 1933-2024Particular specification for MR injector (English PDF)

5.13 Marks and accompanying documents

5.13.1 Injector marks The injector mark shall meet the following requirements.

a) Each part of the injector is provided with magnetic resonance environment safety mark; NOTE. Magnetic resonance environment safety marks shall comply with ASTM F2503-20 requirements.

b) The additional mark of magnetic resonance condition-safe products shall at least indicate the applicable magnetic field strength and safety distance.

5.13.2 Accompanying documents Injectors shall be accompanied by documentation including at least instructions for use and technical specifications. The accompanying documents shall contain at least the following information.

a) The strength of the magnetic field suitable for the injector;

b) The safety distance of injector;

c) The list of MRI devices compatible with the injector.

6.5 Pressure limit Set the pressure limit to

0.689 MPa (100 psi) and connect the pressure gauge to the connector. Set the flow rate to 2 mL/s for push injection. Read the pressure at which the injector indicates that the pressure limit has been exceeded and the push injection is stopped. Calculate the deviation between the actual pressure and the set pressure.

6.6 Injection delay time Set the injection delay time. Use a timer to record the time from when the signal is received to when the injection starts. Calculate the deviation of the injection delay time from the set value.

6.7 Scan delay time Set the scan delay time. Use a timer to record the time from the start of injection to the The test medium is distilled water or deionized water. The injection dose is set to the maximum value. The flow rate is set to 50% of the minimum value and the maximum value respectively. Under the maximum value condition, use a timer (such as a synchronized stopwatch) to record the time from the start of injection to the end of injection. Use a balance to weigh the distilled water or deionized water. Convert it to volume. Calculate the flow rate deviation. NOTE. To ensure safety, use a measuring tool to collect the injection liquid in the MR room. Immediately after the injection, go outside the MR room and weigh the volume using a balance. Calculate the flow rate.

6.8.3 Signal-to-noise ratio change amount

6.8.3.1 Requirements for test devices For the receiving coil, select the loading conditions to be used for this measurement procedure. The test device shall fill the RF coil specification area body or the RF coil specification area surface. At least two typical molds of the head and body shall be selected for testing.

6.8.3.2 Scan parameters The following sequence shall be used. - 2D single spin echo; - Single layer, centered at ±30 mm (displacement in slice selection direction) of isocenter; - Scanning planes. transverse, sagittal, and coronal in order; - TR = 1000 ms or >= 3T1 of signal-generating material, whichever is greater; - TE = 30 ms or <= (1/3)T2 of signal-generating material, whichever is smaller; - Pixel bandwidth shall be set to a clinically relevant value, which may depend on field strength (e.g., 100 Hz/pixel at

0.5 T, 300 Hz/pixel at

1.5 T, and 600 Hz/pixel at 3 T); - FOV is large enough to cover the test device; - Matrix 256×256; - Slice thickness is 5 mm; and - No signal averaging or phase oversampling allowed. Any deviation from the above parameters shall be clearly stated and justified.

6.8.3.3 Measurement steps The placement of the RF coil and test device shall simulate the typical diagnostic position. After the test device is positioned, wait an appropriate amount of time (e.g. 15 min for a large test device) before scanning to prevent vortex artifacts.

a) SNR measurement without the injector placed in the MRI scanner room. The same layer is scanned twice consecutively (image 1 and image 2). The time between the end of the first scan and the start of the second scan is less than 5 min. No adjustment or calibration shall be performed between the two scans.

b) SNR measurements when the injector is placed at the highest magnetic field strength (T) claimed by the manufacturer and at a safe distance (L) from the front of the scanner and operated at a certain flow rate (the recommended clinical maximum flow rate is

4.0 mL/s). When the injector starts running, scan the same layer twice in succession (Image 3 and Image 4). The time between the end of the first scan and the start of the second scan is less than 5 min. No adjustment or calibration shall be performed between the two scans. No adjustment or calibration is performed during the tests

6.8.3.4 Signal-to-noise ratio calculation The region of interest shall be a centered, regular geometric area that encloses at least 85% of the image area of the signal generating volume of the test device. Step

6.8.4 Image artifact variation

6.8.4.1 Requirements for test devices The size of the test device in the phase encoding direction shall not exceed 50% of the image field of view. The test device shall be large enough to permit measurement of an appropriate signal region of interest. The size of the test device in the frequency encoding direction shall not exceed 80% of the image field of view. Because both loaded and unloaded measurements are sensitive to variations in the rest of the MR system (although loaded conditions are likely to be more representative of clinical conditions), either is acceptable for use in this measurement procedure. At least two typical molds of the head and body shall be selected for testing.

6.8.4.2 Scan parameters The following sequence shall be used. - 2D single gradient echo; - Single-slice sequence, centered at ±30 mm (displacement in slice selection direction) of isocenter; - Scanning planes. transverse, sagittal, and coronal in order; - TR = 603 ms; - TE = 25 ms; - Flip angle = 30°; - Slice thickness is 10 mm; - Head coil field of view is 250 mm; - Body coil field of view is 440 mm (or the maximum field of view allowed by the equipment); - Pixel bandwidth shall be set to a clinically relevant value, which may depend on field strength (e.g., 100 Hz/pixel at

0.5 T, 300 Hz/pixel at

1.5 T, and 600 Hz/pixel at 3 T); - Field of view shall be square; - Matrix 192×192 or higher; - Signal averaging is not allowed; - All smoothing or resolution enhancement filters are turned off; and - No phase oversampling is allowed; to check this assumption, check that the sweep time is approximately equal to the number of phase encodings times TR. Any deviation from the above parameters shall be clearly stated and justified.

6.8.4.3 Artifact measurement The placement of the test device in the RF coil shall simulate the typical diagnostic position (same position as in 6.8.3). After positioning the test device, wait for an appropriate time (15 min for a large test device) before scanning to prevent vortex artifacts. To check the stability of the test device filling fluid, repeat the acquisition until the fluid shows no signal inhomogeneities due to vortexes.

a) The injector is not placed in the MRI scanning room for image scanning (Image 7);

b) The injector is placed at the highest magnetic field strength (T) and safe distance (L) from the front of the scanner as claimed by the manufacturer. It is run at a certain flow rate (the recommended clinical maximum flow rate is

4.0 mL/s). The image scan is performed again (Image 8). No adjustment or calibration is performed during the tests