In vivo T2-based MR thermometry in adipose tissue layers for high-intensity focused ultrasound near-field monitoring

Paul Baron; Mario Ries; Roel Deckers; Martijn De Greef; Jukka Tanttu; Max Köhler; Max A. Viergever; Chrit T.W. Moonen; Lambertus W. Bartels

doi:10.1002/mrm.25025

In vivo T2-based MR thermometry in adipose tissue layers for high-intensity focused ultrasound near-field monitoring

Paul Baron, Mario Ries, Roel Deckers, Martijn De Greef, Jukka Tanttu, Max Köhler, Max A. Viergever, Chrit T.W. Moonen, Lambertus W. Bartels

Research output: Contribution to journal › Article › peer-review

52 Citations (Scopus)

Abstract

Purpose: During MR-guided high-intensity focused ultrasound (HIFU) therapy, ultrasound absorption in the near field represents a safety risk and limits efficient energy deposition at the target. In this study, we investigated the feasibility of using T₂ mapping to monitor the temperature change in subcutaneous adipose tissue layers. Methods: The T₂ temperature dependence and reversibility was determined for fresh adipose porcine samples. The accuracy was evaluated by comparing T₂-based temperature measurements with probe readings in an ex vivo HIFU experiment. The in vivo feasibility of T₂-based thermometry was studied during HIFU ablations in the liver in pigs and of uterine fibroids in human patients. Results: T₂ changed linearly and reversibly with temperature with an average coefficient of 5.260.1 ms/C. For the ex vivo HIFU experiment, the difference between the T₂-based temperature change and the probe temperature was <0.9C. All in vivo experiments showed temperature-related T₂ changes in the near field directly after sonications. As expected, considerable intersubject variations in the cooling times were measured in the in vivo porcine experiments. Conclusions: The reversibility and linearity of the T₂-temperature dependence of adipose tissue allows for the monitoring of the temperature in the subcutaneous adipose tissue layers.

Original language	English
Pages (from-to)	1057-1064
Number of pages	8
Journal	Magnetic Resonance in Medicine
Volume	72
Issue number	4
DOIs	https://doi.org/10.1002/mrm.25025
Publication status	Published - Oct 2014
Externally published	Yes

Keywords

High-intensity focused ultrasound
MR thermometry
T mapping
Thermal therapy

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10.1002/mrm.25025

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@article{f971ba45001e4bedb1bbe937313a39bb,

title = "In vivo T2-based MR thermometry in adipose tissue layers for high-intensity focused ultrasound near-field monitoring",

abstract = "Purpose: During MR-guided high-intensity focused ultrasound (HIFU) therapy, ultrasound absorption in the near field represents a safety risk and limits efficient energy deposition at the target. In this study, we investigated the feasibility of using T2 mapping to monitor the temperature change in subcutaneous adipose tissue layers. Methods: The T2 temperature dependence and reversibility was determined for fresh adipose porcine samples. The accuracy was evaluated by comparing T2-based temperature measurements with probe readings in an ex vivo HIFU experiment. The in vivo feasibility of T2-based thermometry was studied during HIFU ablations in the liver in pigs and of uterine fibroids in human patients. Results: T2 changed linearly and reversibly with temperature with an average coefficient of 5.260.1 ms/C. For the ex vivo HIFU experiment, the difference between the T2-based temperature change and the probe temperature was <0.9C. All in vivo experiments showed temperature-related T2 changes in the near field directly after sonications. As expected, considerable intersubject variations in the cooling times were measured in the in vivo porcine experiments. Conclusions: The reversibility and linearity of the T2-temperature dependence of adipose tissue allows for the monitoring of the temperature in the subcutaneous adipose tissue layers.",

keywords = "High-intensity focused ultrasound, MR thermometry, T mapping, Thermal therapy",

author = "Paul Baron and Mario Ries and Roel Deckers and {De Greef}, Martijn and Jukka Tanttu and Max K{\"o}hler and Viergever, {Max A.} and Moonen, {Chrit T.W.} and Bartels, {Lambertus W.}",

note = "Publisher Copyright: {\textcopyright} 2013 Wiley Periodicals, Inc.",

year = "2014",

month = oct,

doi = "10.1002/mrm.25025",

language = "English",

volume = "72",

pages = "1057--1064",

journal = "Magnetic Resonance in Medicine",

issn = "0740-3194",

publisher = "John Wiley & Sons Inc.",

number = "4",

}

TY - JOUR

T1 - In vivo T2-based MR thermometry in adipose tissue layers for high-intensity focused ultrasound near-field monitoring

AU - Baron, Paul

AU - Ries, Mario

AU - Deckers, Roel

AU - De Greef, Martijn

AU - Tanttu, Jukka

AU - Köhler, Max

AU - Viergever, Max A.

AU - Moonen, Chrit T.W.

AU - Bartels, Lambertus W.

PY - 2014/10

Y1 - 2014/10

N2 - Purpose: During MR-guided high-intensity focused ultrasound (HIFU) therapy, ultrasound absorption in the near field represents a safety risk and limits efficient energy deposition at the target. In this study, we investigated the feasibility of using T2 mapping to monitor the temperature change in subcutaneous adipose tissue layers. Methods: The T2 temperature dependence and reversibility was determined for fresh adipose porcine samples. The accuracy was evaluated by comparing T2-based temperature measurements with probe readings in an ex vivo HIFU experiment. The in vivo feasibility of T2-based thermometry was studied during HIFU ablations in the liver in pigs and of uterine fibroids in human patients. Results: T2 changed linearly and reversibly with temperature with an average coefficient of 5.260.1 ms/C. For the ex vivo HIFU experiment, the difference between the T2-based temperature change and the probe temperature was <0.9C. All in vivo experiments showed temperature-related T2 changes in the near field directly after sonications. As expected, considerable intersubject variations in the cooling times were measured in the in vivo porcine experiments. Conclusions: The reversibility and linearity of the T2-temperature dependence of adipose tissue allows for the monitoring of the temperature in the subcutaneous adipose tissue layers.

AB - Purpose: During MR-guided high-intensity focused ultrasound (HIFU) therapy, ultrasound absorption in the near field represents a safety risk and limits efficient energy deposition at the target. In this study, we investigated the feasibility of using T2 mapping to monitor the temperature change in subcutaneous adipose tissue layers. Methods: The T2 temperature dependence and reversibility was determined for fresh adipose porcine samples. The accuracy was evaluated by comparing T2-based temperature measurements with probe readings in an ex vivo HIFU experiment. The in vivo feasibility of T2-based thermometry was studied during HIFU ablations in the liver in pigs and of uterine fibroids in human patients. Results: T2 changed linearly and reversibly with temperature with an average coefficient of 5.260.1 ms/C. For the ex vivo HIFU experiment, the difference between the T2-based temperature change and the probe temperature was <0.9C. All in vivo experiments showed temperature-related T2 changes in the near field directly after sonications. As expected, considerable intersubject variations in the cooling times were measured in the in vivo porcine experiments. Conclusions: The reversibility and linearity of the T2-temperature dependence of adipose tissue allows for the monitoring of the temperature in the subcutaneous adipose tissue layers.

KW - High-intensity focused ultrasound

KW - MR thermometry

KW - T mapping

KW - Thermal therapy

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ER -

In vivo T2-based MR thermometry in adipose tissue layers for high-intensity focused ultrasound near-field monitoring

Abstract

Keywords

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