55 Mn-based fiducial markers for rapid and automated RF coil localization for hyperpolarized 13 C MRI

© 2020 International Society for Magnetic Resonance in Medicine..

PURPOSE: To use fiducial markers containing manganese 55 to rapidly localize carbon 13 (13 C) RF coils for correcting images for B1 variation.

METHODS: Hollow high-density polyethylene spheres were filled with 3M sodium permanganate and affixed to a rectangular 13 C-tuned RF coil. The relative positions of the markers and coil conductors were mapped using CT. Marker positions were measured by MRI using a series of 1D projections and automated peak detection. Once the coil location was determined, coil sensitivity was estimated using a quasi-static calculation. Simulations were performed to determine the minimum number of projections required for robust localization. Phantom experiments were used to confirm the accuracy of marker localization as well as the calculated coil sensitivity. Finally, in vivo validation was performed using hyperpolarized 13 C pyruvate in a rat model.

RESULTS: In simulations, our algorithm was accurate in determining marker positions when at least 6 projections were used (RMSE 1.4 ± 0.9 mm). These estimates were verified in phantom experiments, where markers locations were determined with an RMS accuracy of 1.3 mm. A minimum SNR of 4 was required for automated detection to perform accurately. Computed coil sensitivity had a median error of 17% when taken over the entire measured area and 5.7% over a central region. In a rat, correction for nonuniform reception and flip angle was able to normalize the signals arising from asymmetrically positioned kidneys.

CONCLUSION: Manganese 55 fiducial markers are an inexpensive and reliable method for rapidly localizing 13 C RF coils and correcting 13 C images for B1 variation without user intervention.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:85

Enthalten in:

Magnetic resonance in medicine - 85(2021), 1 vom: 01. Jan., Seite 518-530

Sprache:

Englisch

Beteiligte Personen:

Ohliger, Michael A [VerfasserIn]
Gordon, Jeremy W [VerfasserIn]
Carvajal, Lucas [VerfasserIn]
Larson, Peder E Z [VerfasserIn]
Ou, Jao J [VerfasserIn]
Agarwal, Shubhangi [VerfasserIn]
Zhu, Zihan [VerfasserIn]
Vigneron, Daniel B [VerfasserIn]
von Morze, Cornelius [VerfasserIn]

Links:

Volltext

Themen:

Coil sensitivity
Fiducials
Hyperpolarized carbon
Journal Article
Manganese
RF coil
Research Support, N.I.H., Extramural

Anmerkungen:

Date Completed 14.05.2021

Date Revised 02.01.2022

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1002/mrm.28424

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM313135444