CST – Computer Simulation Technology

Comparison between Simulated Decoupling Regimes for Specific Absorption Rate Prediction in Parallel Transmit MRI
Arian Beqiri, Jeffrey W. Hand, Joseph V. Hajnal, Shaihan J. Malik
Magnetic Resonance in Medicine
pp. 1 - 12
SAR, modeling, parallel transmission
Purpose The use of electromagnetic (EM) modeling is critical for specific absorption rate (SAR) characterization in parallel transmission MRI. Radiofrequency arrays that include decoupling networks can be difficult to characterize accurately in simulation. A practical method of simplifying modeling is to exclude the decoupling networks and model each transmit element in isolation. Results from this type of model can be related to a real device by applying “active decoupling” to the real device to suppress residual coupling when in use. Here, we compare this approach with a full model that includes decoupling networks. Methods EM simulations for a variety of adult male voxel models placed within an eight-channel transverse electromagnetic (TEM) array tuned for 3 Tesla operation were run with and without decoupling networks included. The resulting EM fields and SAR estimates were compared using basic normalization, and simulated active decoupling. Results Modeling the transmit elements independently leads to variations which have significantly different SAR estimates of ~20% on average compared with the full model if not normalized appropriately. After “active decoupling,” SAR was still generally seen to be overestimated by ~7% with independent channel modeling; despite having similar B1+ field distributions. Conclusion Modeling transmission elements independently may lead to substantially incorrect SAR estimates if the corresponding MRI system is not run in an analogous manner.

Back to References

contact support

Your session has expired. Redirecting you to the login page...

We use cookie to operate this website, improve its usability, personalize your experience, and track visits. By continuing to use this site, you are consenting to use of cookies. You have the possibility to manage the parameters and choose whether to accept certain cookies while on the site. For more information, please read our updated privacy policy

Cookie Management

When you browse our website, cookies are enabled by default and data may be read or stored locally on your device. You can set your preferences below:

Functional cookies

These cookies enable additional functionality like saving preferences, allowing social interactions and analyzing usage for site optimization.

Advertising cookies

These cookies enable us and third parties to serve ads that are relevant to your interests.