Magnetic resonance equipment for medical imaging – Part 1: Determination of essential image quality parameters
|Publication Date:||1 December 2018|
|ICS Code (Radiographic equipment):||11.040.50|
This part of IEC 62464 specifies measurement procedures for the determination of many essential image quality parameters for MR EQUIPMENT. Measurement procedures as addressed in this document are suitable for
- quality assessment in the ACCEPTANCE TEST, and
- quality assurance in the CONSTANCY TEST.
Required levels of performance for ACCEPTANCE TESTS are not provided for all tests.
This document does not address
- image quality assessment of MR EQUIPMENT with a static magnetic field intensity greater than 8 Tesla, if not otherwise stated,
- image quality affected by MR-compatibility issues,
- special diagnostic procedures such as flow imaging, perfusion, diffusion, radiotherapy and image-guided therapy applications, and
- TYPE TESTS.
The scope of this document is also limited to measuring image quality characteristics in images acquired on TEST DEVICES, not in PATIENT images.
The measurement procedures specified in this document are directed to
- MANUFACTURERS, who can demonstrate compliance by performing ACCEPTANCE and CONSTANCY TESTS as described by this document,
- test houses, who can confirm performance of MR EQUIPMENT using methods described in this document,
- regulatory authorities, who can reference this document, and
- RESPONSIBLE ORGANISATIONS who want to perform ACCEPTANCE and CONSTANCY TESTS using methods described in this document
The essential image quality parameters and measurement methodologies defined in this document are
- SIGNAL TO NOISE RATIO,
- SLICE THICKNESS in 2-D scanning,
- 2-D GEOMETRIC DISTORTION,
- SPATIAL RESOLUTION, and
- GHOSTING ARTEFACTS.
Each of these procedures can be performed standalone or in combination with any of the other procedures.
This document describes the preferred measurement procedures. It also describes alternative normative methods in Annex A. The preferred test methods may be substituted with these alternative normative methods. If necessary, other methods not described in this document can be used, provided those other test methods are documented and validated against the methods described in the document: it means an analysis is done by comparison to the original method that demonstrates a similar, or better, level of sensitivity to the same parameter of interest and a similar, or better, level of robustness against unrelated parameters. All methods will produce quantitative results.
The rationale to the preferred and alternate methods, and their pitfalls, are described in Annex B.
This document also presents requirements for CONSTANCY TESTS suitable for MR EQUIPMENT quality assurance programs concerning essential image quality parameters. There are no preferred CONSTANCY TEST methods, to provide flexibility in using existing automated procedures where available, but suggested examples of test methods can be found in Annex A. This document places an emphasis on consistently repeatable, automated measuring tools that facilitate trend analysis and the frequent quick testing of a small set of important parameters that are sensitive to the overall operating characteristics of the MR EQUIPMENT.
NOTE None of the methods found in this document have been extensively tested at a static magnetic field intensity above 3 T. Initial tests indicate the methods function correctly when appropriate TEST DEVICE fillers are used.