YY/T 1933-2024 PDF English
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Particular specification for MR injector
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YY/T 1933-2024: PDF in English (YYT 1933-2024) YY/T 1933-2024
YY
MEDICAL INDUSTRY STANDARD OF
THE PEOPLE’S REPUBLIC OF CHINA
ICS 11.040.50
CCS C 39
Particular specification for MR injector
ISSUED ON. JULY 08, 2024
IMPLEMENTED ON. JULY 20, 2025
Issued by. National Medical Products Administration
Table of Contents
Foreword... 3
1 Scope... 4
2 Normative references... 4
3 Terms and definitions... 4
4 Composition and classification... 7
5 Requirements... 7
6 Test methods... 10
Bibliography... 20
Particular specification for MR injector
1 Scope
This document specifies the requirements for magnetic resonance (MR) injector
(hereinafter referred to as injectors) and describes the corresponding test methods.
This document applies to injectors.
This document does not apply to single-use high-pressure contrast syringes and their
accessories dedicated to injectors.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
GB 9706.224, Medical electrical equipment -- Part 2-24.Particular requirements
for the basic safety and essential performance of infusion pumps and controllers
YY/T 0482, Medical Magnetic Resonance Imaging Equipment -- Determination of
Main Image Quality Parameters
YY/T 0935, Particular specifications for CT injector
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in GB 9706.224,
YY/T 0935, YY/T 0482 as well as the followings apply.
3.1 MR injector
A device that in the diagnosis of magnetic resonance imaging, in order to obtain the
required medical images, the contrast agent is injected into the human body according
to the set flow rate and injection dose in conjunction with the magnetic resonance
equipment.
3.2 injector head
An interface component for injection push mechanism and installation of matching
syringe.
3.10 keep-vein-open rate; KVO
Under specified conditions, the injector returns to a predetermined low speed state
while keeping the patient line open.
NOTE. The abbreviation KOR (keep open rate) is often used as a synonym for KVO.
[Source. GB 9706.224-2021, 201.3.209, modified]
3.11 signal to noise ration; SNR
The quotient of the signal value divided by the noise value.
[Source. YY/T 0482-2022, 3.1.26]
3.12 signal-to-noise ratio change
Changes in the signal-to-noise ratio of the reference image when the instrument is
working and when the instrument is not working.
3.13 magnetically induced displacement force
The force exerted on a magnetic object exposed to the spatial gradient of a static
magnetic field.
NOTE. This force is expected to cause objects to move in the spatial gradient of the static magnetic
field.
[Source. ASTM F2503-20, 3.1.4]
3.14 magnetically induced displacement
A magnetic object in a spatial gradient magnetic field moves toward a magnetic
resonance device due to the magnetically induced displacement force.
3.15 artifact
What is visible in the image neither reflects the structure of the corresponding position
in the object nor can it be explained by noise.
[Source. YY/T 0482-2022, 3.1.2]
3.16 immunity (to a disturbance)
The ability of me equipment or me system to operate without degradation in the
presence of electromagnetic disturbances.
[Source. YY 9706.102-2021, 3.13]
3.17 region of interest
safety distance, the injector shall not produce magnetically induced displacement.
If the injector has casters, verify that the casters are unlocked.
NOTE. The magnetic induction value is generally regarded as the field strength value of the
magnetic field, with the unit of T. Bo is the static magnetic field generated by the magnetic resonance
device and its accessories. Scalars are generally represented by ordinary fonts (such as B). Bold
fonts represent vectors (such as B).
5.8.2 Immunity
The injector shall be able to operate normally at the applicable magnetic field strength
and the safety distance claimed by the manufacturer. The basic performance of the flow
rate shall not be reduced.
The flow rate shall meet the requirements of 5.1.
5.8.3 Signal-to-noise ratio change amount
At the applicable magnetic field strength and the claimed safety distance claimed by
the manufacturer, the variation in the signal-to-noise ratio of the reference image when
the injector is injecting and when there is no injector shall be less than ±10%.
5.8.4 Image artifact variation
At the applicable magnetic field strength and the safety distance claimed by the
manufacturer, the change in the ratio of the artifact signal value to the signal average
value in the magnetic resonance imaging reference image when the injector is injecting
and when there is no injector shall meet the requirements specified by the manufacturer.
NOTE. The change limit is determined by the manufacturer based on the applicable magnetic field
strength and the adapted magnetic resonance equipment.
5.9 Injector head rotation angle
If applicable, when the injector head is pointing upwards, ensure that all air in the
syringe is exhausted. When it is pointing downwards, the angle between it and the
horizontal plane shall be no less than 10°.
5.10 KVO features
The manufacturer shall specify the KVO interval, KVO dose per injection and deviation,
if applicable.
5.11 Functions
The injector shall have the following functions.
a) Injection time display, injection dosage display, flow rate setting or display;
b) When the injection pressure exceeds the pressure limit, a prompt shall be given
and the injection shall be stopped;
c) It shall have the function of controlling injection and stop outside the scanning
room;
d) The injection shall be able to be stopped at any time during the injection process.
5.12 Appearance
It shall meet the following requirements.
a) The surface shall be clean, uniform in color, free of sharp edges, burrs, scratches,
cracks and other defects;
b) The control device shall be firmly fixed and the control shall be reliable.
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 Test methods
6.1 Flow rate
The test medium is distilled water or deionized water. The injection dose is set to the
maximum value. The flow rate is set to the minimum value, 50% of the maximum value,
and the maximum value. 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.
6.2 Injection dose
The test medium is distilled water or deionized water. The injection dose is set to the
minimum value (flow rate is the minimum value), 50% of the maximum value (flow
rate is 50% of the maximum value), and the maximum value (flow rate is the maximum
value) to complete the injection. Use a balance to weigh the distilled water or deionized
water. Convert it to volume. Calculate the injection dose deviation.
6.3 Fill rate
The test medium is distilled water or deionized water. The fill dose is set to the
maximum value, and the fill rate is set to the minimum value, 50% of the maximum
value, and the maximum value. Use a timer (such as a synchronized stopwatch) to
record the time from the start of fill to the end of fill. Use a balance to weigh the distilled
water or deionized water. Convert it to volume. Calculate the fill rate deviation.
6.4 Maximum injection pressure
Check the risk management documentation and verify the following.
Set the pressure limit to the maximum value of the injector and connect the pressure
gauge to the connector. Set the maximum flow rate for push injection. Read the pressure
at which the injector indicates that the pressure limit has been exceeded and the push
injection is stopped. It shall not be greater than the provisions of 5.4.
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 a) and b).
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 1.Determine the average pixel value within the region of interest in image 1.The
result (minus any baseline pixel deviation) shall be called the image signal Sbefore.
Step 2.Calculate the pixel-by-pixel difference to get Image 5, as follows. Image 5 =
Image 1 - Image 2.
The subtraction process shall avoid erroneous results, that is, pixel values that exceed
the minimum (or maximum) pixel value allowed by the MRI device (for example,
negative values).
Step 3.Reference the region of interest used to measure Sbefore in step 1 to the same
position in image 5 and calculate the standard deviation of the region of interest
(SDbefore).
Step 4.Calculate SNR.
The signal-to-noise ratio changes of the three image scanning layers of each mold,
namely the cross-section, sagittal and coronal planes, meet the requirements of 5.8.3.
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 a) and b).
6.8.4.4 Artifact calculation
Set the window width to 1.Vary the window position until the brightest artifact appears
in the phase encoding direction. Place a 25 (5×5) pixel region of interest over the artifact.
Make sure the region of interest does not contain any portion of possible “digital zero”
pixels generated by the gradient distortion correction filter (if applicable).
Measure and record the mean of the region of interest as the average artifact signal
value, IG. (1 in Figure 2 is the region of interest for average artifact measurement)
Measure and record the average signal, S, of a region of interest of at least 25 pixels
within the test device. (2 in Figure 2 is the region of interest for the average signal
measurement)
Calculate the ratio of artifact to signal = IG/S.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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