Preliminary assessment of one-dimensional MR elastography for use in monitoring focused ultrasound therapy

Le Yuan, Kevin J. Glaser, Olivier Rouviere, Krzysztof R. Gorny, Shigao D Chen, Armando Manduca, Richard Lorne Ehman, Joel P. Felmlee

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The purpose of this work is to assess a fast technique that measures tissue stiffness and temperature during focused ultrasound thermal therapy (FUS). A one-dimensional (1D) MR elastography (MRE) pulse sequence was evaluated for the purpose of obtaining rapid measurements of thermally induced changes in tissue stiffness and temperature for monitoring FUS treatments. The accuracy of the 1D measurement was studied by comparing tissue displacements measured by 1D MRE with those measured by the well-established 2D MRE pulse sequence. The reproducibility of the 1D MRE measurement was assessed, in gel phantoms and ex vivo porcine tissue, for varied FUS intensity levels (31.5-199.9 W cm -2) and over a range of displacements at the focus (0.1-1 μm). Temperature elevations in agarose gel phantoms were measured using 1D MRE and calibrated using fiberoptic-thermometer-based measurements. The 1D MRE displacement measurements are highly correlated with those obtained with the 2D technique (R2 = 0.88-0.93), indicating that 1D MRE can successfully measure tissue displacement. Ten repeated trials at each FUS power level yielded a minimum detectable displacement change of 0.2 μm in phantoms and 0.4 μm in tissue (at 95% confidence level). The 1D MRE temperature measurements correlated well with temperature changes measured simultaneously with fiberoptic thermometers (R2 = 0.97). The 1D MRE technique is capable of detecting tissue displacements as low as 0.4 μm, which is an order of magnitude smaller than 5 μm displacements expected during FUS therapy (Le et al 2005 AIP Conf. Proc.: Ther. Ultrasound 829 186-90). Additionally, 1D MRE was shown to provide adequate measurements of temperature elevations in tissue. These findings indicate that 1D MRE may be an effective tool for monitoring FUS treatments.

Original languageEnglish (US)
Article number012
Pages (from-to)5909-5919
Number of pages11
JournalPhysics in Medicine and Biology
Volume52
Issue number19
DOIs
StatePublished - Sep 21 2007

Fingerprint

Elasticity Imaging Techniques
therapy
Ultrasonics
Tissue
Monitoring
Temperature
Thermometers
thermometers
Therapeutics
stiffness
Gels
temperature
Stiffness
gels
Displacement measurement
displacement measurement
pulses
Temperature measurement
temperature measurement
confidence

ASJC Scopus subject areas

  • Biomedical Engineering
  • Physics and Astronomy (miscellaneous)
  • Radiology Nuclear Medicine and imaging
  • Radiological and Ultrasound Technology

Cite this

Preliminary assessment of one-dimensional MR elastography for use in monitoring focused ultrasound therapy. / Yuan, Le; Glaser, Kevin J.; Rouviere, Olivier; Gorny, Krzysztof R.; Chen, Shigao D; Manduca, Armando; Ehman, Richard Lorne; Felmlee, Joel P.

In: Physics in Medicine and Biology, Vol. 52, No. 19, 012, 21.09.2007, p. 5909-5919.

Research output: Contribution to journalArticle

Yuan, Le ; Glaser, Kevin J. ; Rouviere, Olivier ; Gorny, Krzysztof R. ; Chen, Shigao D ; Manduca, Armando ; Ehman, Richard Lorne ; Felmlee, Joel P. / Preliminary assessment of one-dimensional MR elastography for use in monitoring focused ultrasound therapy. In: Physics in Medicine and Biology. 2007 ; Vol. 52, No. 19. pp. 5909-5919.
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