Optimization of self‐reference thermometry using complex field estimation

Kuroda, Kagayaki; Kokuryo, Daisuke; Kumamoto, Etsuko; Suzuki, Kyohei; Matsuoka, Yuichiro; Keserci, Bilgin

doi:10.1002/mrm.21016

Cited by 57 publications

(62 citation statements)

References 12 publications

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“…One approach, called referenceless thermometry or self-referenced thermometry, tries to estimate the heating from every individual image itself, without a preheating reference scan. The background phase inside the heating region is estimated by fitting a polynomial function to the un-wrapped background phase (98) or a complex valued polynomial (99) to the complex image outside the heating region using a weighted least-squares fit. The extrapolation of the polynomial to the heated region serves as the background phase estimate, which is then subtracted from the actual phase.…”

Section: Prf Thermometry and Motionmentioning

confidence: 99%

MR thermometry

Rieke

Pauly

2008

Magnetic Resonance Imaging

1,022

952

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Minimally invasive thermal therapy as local treatment of benign and malignant diseases has received increasing interest in recent years. Safety and efficacy of the treatment require accurate temperature measurement throughout the thermal procedure. Noninvasive temperature monitoring is feasible with magnetic resonance (MR) imaging based on temperature-sensitive MR parameters such as the proton resonance frequency (PRF), the diffusion coefficient (D), T 1 and T 2 relaxation times, magnetization transfer, the proton density, as well as temperature-sensitive contrast agents. In this article the principles of temperature measurements with these methods are reviewed and their usefulness for monitoring in vivo procedures is discussed. Whereas most measurements give a temperature change relative to a baseline condition, temperature-sensitive contrast agents and spectroscopic imaging can provide absolute temperature measurements. The excellent linearity and temperature dependence of the PRF and its near independence of tissue type have made PRF-based phase mapping methods the preferred choice for many in vivo applications. Accelerated MRI imaging techniques for real-time monitoring with the PRF method are discussed. Special attention is paid to acquisition and reconstruction methods for reducing temperature measurement artifacts introduced by tissue motion, which is often unavoidable during in vivo applications.

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Section: Prf Thermometry and Motionmentioning

confidence: 99%

MR thermometry

Rieke

Pauly

2008

Magnetic Resonance Imaging

1,022

952

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“…Based on a region unaffected by thermal changes or a region unaffected by a thermal phase shift (fat) around the region of interest for thermal monitoring, the background phase information is fitted by a polynomial function (23,49,80,81). Using a reweighted regression even regions affected by thermal changes can be used to estimate the background phase (82).…”

Section: Motionmentioning

confidence: 99%

Magnetic resonance thermometry: Methodology, pitfalls and practical solutions

Winter

Oberacker

Paul

et al. 2015

International Journal of Hyperthermia

188

165

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Clinically established thermal therapies like thermo ablative approaches or adjuvant hyperthermia treatment rely on accurate thermal dose information for the evaluation and adaptation of the thermal therapy. Intratumoral temperature measurements have been correlated successfully with clinical endpoints. Magnetic resonance imaging is the most suitable technique for non-invasive thermometry avoiding complications related to invasive temperature measurements. Since the advent of MR thermometry two decades ago, numerous MR thermometry techniques have been developed continuously increasing accuracy and robustness for in vivo applications. While this progress was primarily focused on relative temperature mapping, current and future efforts will likely close the gap towards quantitative temperature readings. These efforts are essential to benchmark thermal therapy efficiency, understand temperature related biophysical and physiological processes and to use these insights to set new landmarks for diagnostic and therapeutic applications. With that in mind, this review summarizes and discusses advances in MR thermometry providing practical considerations, pitfalls and technical obstacles constraining temperature measurement accuracy, spatial and temporal resolution in vivo. Established approaches and current trends in thermal therapy hardware are surveyed with respect to potential benefits for MR thermometry.3

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“…Some schemes called referenceless PRF thermometry, or self-reference methods have been devised and optimized to overcome this problem (17,29), in which the baseline phase of the heated ROI is estimated by extrapolating the phase in the surrounding tissue. Subtracting the estimated baseline phase from the actual phase under heated condition, the temperature distribution in the heated region can be obtained.…”

Section: Discussionmentioning

confidence: 99%

“…For example, Botnar et al used the PRF technique to acquire and generate temperature maps after radio frequency (RF) ablation with an open 0.5T MRI system under ex vivo and in vivo conditions (16), and Kuroda et al developed a self-reference thermometry technique using complex field estimation and optimized the technique for 0.5T (17). The developments and applications of temperature mapping have been mostly done at 1.5T and 3T (15,(18)(19)(20).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of MR thermometry with proton resonance frequency method at 7T

Wang¹

2017

Quant. Imaging Med. Surg.

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Quantitative and non-invasive temperature mapping using magnetic resonance imaging (MRI) provides a unique way to measure temperature evolution inside biological tissues. The method is widely used in thermal ablation procedures with magnetic fields at or below 3T. In this paper, the sensitivity of the MRI thermometry at 7T was studied using a proton resonance frequency (PRF)-based technique. We first used an agarose gel phantom with MR-compatible thermometry to calibrate the temperature coefficient, and then this temperature coefficient was employed to measure the internal temperature in both ex vivo (beef muscle) and in vivo (rat) experiments using focused ultrasound heating. The temperature coefficient calibrated by the phantom was 0.0095 ppm/℃, and both the ex vivo and in vivo experiments exhibited clear temperature evolution. This quantitative study confirmed the sensitivity (<1 ℃) of MR temperature mapping at 7T.

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Optimization of self‐reference thermometry using complex field estimation

Cited by 57 publications

References 12 publications

MR thermometry

MR thermometry

Magnetic resonance thermometry: Methodology, pitfalls and practical solutions

Evaluation of MR thermometry with proton resonance frequency method at 7T

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