The utility of pelvic coil SNR testing in the quality assurance of a clinical MRgFUS system

Krzysztof R. Gorny, Nicholas J. Hangiandreou, Heidi A. Ward, Gina K. Hesley, Douglas L. Brown, Joel P. Felmlee

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

During MRI-guided focused ultrasound (MRgFUS) treatments of uterine fibroids using ExAblate2000, tissue ablations are delivered by a FUS transducer while MR imaging is performed with a pelvic receiver coil. The consistency of the pelvic coil performance is crucial for reliable MR temperature measurements as well as detailed anatomic imaging in patients. Test sonications in a gel phantom combined with MR thermometry are used to test the performance of the FUS transducer prior to each treatment. As we show, however, these tests do not adequately evaluate receiver coil performance prior to clinical use. This could become a problem since the posterior part of the coil is frequently moved and can malfunction. The aim of this work is to demonstrate the utility of the signal-to-noise ratio (SNR) as a reliable indicator of pelvic coil performance. Slight modification of the vendor-provided coil support was accomplished to assure reproducible coil positioning. The SNR was measured in a gel phantom using axial acquisitions from the 3D-localizer scan. MR temperature and SNR measurements were obtained using a degraded receiver coil (with posterior element removed) and a known faulty coil, and compared to those obtained with a fully functioning coil. While the MR temperature-based tests were insensitive to change in pelvic coil performance, (degraded, p = 0.24; faulty, p = 0.28), the SNR tests were highly sensitive to coil performance, (degraded, p < 0.001; faulty, p < 0.001). Additional clinical data illustrate the utility of SNR testing of the receiver coil. These tests require minimal (or possibly no) additional scan time and have proven to be effective in our clinical practice.

Original languageEnglish (US)
JournalPhysics in Medicine and Biology
Volume54
Issue number7
DOIs
StatePublished - 2009

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Signal-To-Noise Ratio
Transducers
Temperature
Gels
Thermometry
Sonication
Leiomyoma
Therapeutics

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

Cite this

Gorny, K. R., Hangiandreou, N. J., Ward, H. A., Hesley, G. K., Brown, D. L., & Felmlee, J. P. (2009). The utility of pelvic coil SNR testing in the quality assurance of a clinical MRgFUS system. Physics in Medicine and Biology, 54(7). https://doi.org/10.1088/0031-9155/54/7/N01

The utility of pelvic coil SNR testing in the quality assurance of a clinical MRgFUS system. / Gorny, Krzysztof R.; Hangiandreou, Nicholas J.; Ward, Heidi A.; Hesley, Gina K.; Brown, Douglas L.; Felmlee, Joel P.

In: Physics in Medicine and Biology, Vol. 54, No. 7, 2009.

Research output: Contribution to journalArticle

Gorny, Krzysztof R. ; Hangiandreou, Nicholas J. ; Ward, Heidi A. ; Hesley, Gina K. ; Brown, Douglas L. ; Felmlee, Joel P. / The utility of pelvic coil SNR testing in the quality assurance of a clinical MRgFUS system. In: Physics in Medicine and Biology. 2009 ; Vol. 54, No. 7.
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