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Evaluation of short folded dipole antennas as receive elements of ultra‐high‐field human head array
- Source :
- Magnetic Resonance in Medicine
- Publication Year :
- 2019
- Publisher :
- Wiley, 2019.
-
Abstract
- Purpose: To improve the receive (Rx) performance of a human head transceiver (TxRx) array at 9.4T without compromising its transmit (Tx) performance, a novel 16‐element array was developed, constructed, and tested.Methods: We designed and constructed a phased array, which consists of 8 TxRx surface loops placed in a single row and circumscribing a head, and 8 Rx‐only short folded dipole antennas. Dipoles were positioned along the central axis of each transceiver loop perpendicular to its surface. We evaluated the effect of Rx dipoles on the Tx efficiency of the array and maximum local specific absorption rate (SAR) as compared to the array of 8 surface loops only. We also compared the new array to a 16‐channel array of the same size consisting of 8 TxRx surface loops and 8 Rx‐only vertical loops in terms of Tx efficiency, SAR, and signal‐to‐noise ratio (SNR).Results: The new array improves both peripheral (up to 2 times) and central (1.17 times) SNR as compared to the 16‐element array of the same geometry consisting of 8 TxRx surface loops and 8 Rx‐only vertical loops. We demonstrated that an addition of actively detuned Rx‐only dipole elements produces only a small decrease (~7%) of the equation/mrm27754-math-0001.png transmit field and a small increase (Conclusion: As a proof of concept, we developed and constructed a prototype of a 9.4T (400 MHz) head array consisting of 8 TxRx surface loops and 8 Rx‐only short optimized folded dipoles. We demonstrated that at ultra‐high field, dipoles outperformed Rx‐only vertical loops in vivo.
- Subjects :
- Phased array
Signal-To-Noise Ratio
030218 nuclear medicine & medical imaging
law.invention
03 medical and health sciences
0302 clinical medicine
Optics
law
Perpendicular
Humans
Radiology, Nuclear Medicine and imaging
Dipole antenna
Physics
Human head
Phantoms, Imaging
business.industry
Brain
Specific absorption rate
Equipment Design
Magnetic Resonance Imaging
Dipole
Head (vessel)
Transceiver
business
Head
030217 neurology & neurosurgery
Subjects
Details
- ISSN :
- 15222594 and 07403194
- Volume :
- 82
- Database :
- OpenAIRE
- Journal :
- Magnetic Resonance in Medicine
- Accession number :
- edsair.doi.dedup.....efab6c44aa07c11307ee3c8db8eb4242