NEMA releases new MRI performance standards
The National Electrical Manufacturers Association (NEMA) on Wednesday published four standards that govern the overall quality of magnetic resonance imaging (MRI) systems. The standards are part of a series the organization is releasing to gauge performance of systems in a number of parameters, including noise levels, energy deposition, and electric field strength, the organization said.
The standards are as follows:
In the case of MS 4, it has undergone revision due to the gradient performance of modern MRI scanners that have advanced, making some basic assumptions and guidance in the original standard obsolete.
MS 10 is used for measuring local regions of high Specific Absorption Rate (SAR) from radiofrequency (RF) power deposition. NEMA standard MS 8 is useful for measuring whole-body average SAR. By using both MS 8 and MS 10, it is possible to completely characterize RF power deposition both whole-body and local. MS 11 presents a measurement method for determining gradient-induced electric fields, which affect the safety and comfort of patients. Lastly, MS 12 provides a series of recommendations on how to measure and present the distortion analysis information in order to meet this growing need, NEMA said.
The different standards can be found online at:
The standards are as follows:
- One standard has been revised: MS 4-2006, for Acoustic Noise Measurement Procedure for Diagnostic Magnetic Resonance Imaging Devices; and
- The following are new: MS 10-2006, Determination of Local Specific Absorption Rate (SAR) in Diagnostic Magnetic Resonance Imaging; MS 11-2006, Determination of Gradient-Induced Electric Fields in Diagnostic Magnetic Resonance Imaging; and MS 12-2006, Quantification and Mapping of Geometric Distortion for Special Applications.
In the case of MS 4, it has undergone revision due to the gradient performance of modern MRI scanners that have advanced, making some basic assumptions and guidance in the original standard obsolete.
MS 10 is used for measuring local regions of high Specific Absorption Rate (SAR) from radiofrequency (RF) power deposition. NEMA standard MS 8 is useful for measuring whole-body average SAR. By using both MS 8 and MS 10, it is possible to completely characterize RF power deposition both whole-body and local. MS 11 presents a measurement method for determining gradient-induced electric fields, which affect the safety and comfort of patients. Lastly, MS 12 provides a series of recommendations on how to measure and present the distortion analysis information in order to meet this growing need, NEMA said.
The different standards can be found online at:
- MS 4-2006 at www.nema.org/stds/ms4.cfm
- MS 10-2006 at www.nema.org/stds/ms10.cfm
- MS 11-2006 at www.nema.org/stds/ms11.cfm
- MS 12-2006 at www.nema.org/stds/ms12.cfm