MR thermometry near metallic devices using multispectral imaging. Issue 3 (16th March 2016)

• Record Type: Journal Article
• Authors: Weber, Hans; Taviani, Valentina; Yoon, Daehyun; Ghanouni, Pejman; Pauly, Kim Butts; Hargreaves, Brian A.
• Is Part Of: Magnetic resonance in medicine. Volume 77:Issue 3(2017)
• Page Start: 1162
• Page End: 1169
• Publication Date: 2016-03-16
• Subjects: multispectral imaging -- thermometry -- temperature -- proton resonance frequency shift -- T1 mapping -- distortion correction -- metallic implants -- metal artifacts -- metal‐induced distortions -- susceptibility artifact; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.26203
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: The lack of a technique for MR thermometry near metal excludes a growing patient population from promising treatments such as MR‐guided focused ultrasound therapy. Here we explore the feasibility of multispectral imaging (MSI) for noninvasive temperature measurement in the presence of strong field inhomogeneities by exploiting the temperature dependency of the T1 relaxation time. Methods: A two‐dimensional inversion‐recovery–prepared MSI pulse sequence (2DMSI) was implemented for artifact‐reduced T1 mapping near metal. A series of T1 maps was acquired in a metallic implant phantom while increasing the phantom temperature. The measured change in T1 was analyzed with respect to the phantom temperature. For comparison, proton resonance frequency shift (PRFS) thermometry was performed. Results: 2DMSI achieved artifact‐reduced, single‐slice T1 mapping in the presence of strong off‐resonance with a spatial resolution of 1.9 mm in‐plane and a temporal resolution of 5 min. The maps enabled temperature measurements over a range of 30°C with an uncertainty below 1.4°C. The quality of the resulting temperature maps was independent of the distance from the metal, whereas the PRFS‐based temperature measurements were increasingly impaired with increasing off‐resonance. Conclusion: We demonstrated the ability to noninvasively measure temperature near metal using MSI and the T1 temperature sensitivity. Magn Reson Med 77:1162–1169, 2017. © 2016 International Society for Magnetic Resonance in Medicine