An evaluation of the effects of susceptibility changes on the water chemical shift method of temperature measurement in human peripheral muscle

Young, I. R.; Hajnal, Joseph V.; Roberts, I; Ling, Junxiao; Hill-Cottingham, R.J.; Oatridge, Angela; Wilson, Jason

doi:10.1002/mrm.1910360307

Cited by 62 publications

(40 citation statements)

References 16 publications

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“…The susceptibility change with temperature is 0.0026 ppm/°C in pure water and 0.0016 ppm/°C for muscle tissue in the temperature range of 30°C to 45°C (44). But, whereas the temperature dependence of the chemical shift is nearly constant for all tissue types (with the exception of adipose tissue), the temperature dependence of the susceptibility is tissue type-dependent (60).…”

Section: Temperature Dependence Of the Susceptibilitymentioning

confidence: 91%

MR thermometry

Rieke

Pauly

2008

Magnetic Resonance Imaging

1,019

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: Temperature Dependence Of the Susceptibilitymentioning

confidence: 91%

MR thermometry

Rieke

Pauly

2008

Magnetic Resonance Imaging

1,019

952

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“…On the contrary, diffusion methods still suffer from technical and methodical limitations in clinical practice (26). Therefore, for magnetic fields z1 Tesla, PFSbased methods are preferred by most investigators today (27)(28)(29)(30)(31)(32).…”

Section: Introductionmentioning

confidence: 99%

Noninvasive Magnetic Resonance Thermography of Recurrent Rectal Carcinoma in a 1.5 Tesla Hybrid System

Gellermann¹,

Wlodarczyk²,

Hildebrandt³

et al. 2005

Cancer Research

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To implement noninvasive thermometry, we installed a hybrid system consisting of a radiofrequency multiantenna applicator (SIGMA-Eye) for deep hyperthermia (BSD-2000/3D) integrated into the gantry of a 1.5 Tesla magnetic resonance (MR) tomograph Symphony. This system can record MR data during radiofrequency heating and is suitable for application and evaluation of methods for MR thermography. In 15 patients with preirradiated pelvic rectal recurrences, we acquired phase data sets (25 slices) every 10 to 15 minutes over the treatment time (60-90 minutes) using gradient echo sequences (echo time = 20 ms), transformed the phase differences to MR temperatures, and fused the color-coded MR-temperature distributions with anatomic T1-weighted MR data sets. We could generate one complete series of MR data sets per patient with satisfactory quality for further analysis. In fat, muscle, water bolus, prostate, bladder, and tumor, we delineated regions of interest (ROI), used the fat ROI for drift correction by transforming these regions to a phase shift zero, and evaluated the MR-temperature frequency distributions. Mean MR temperatures (T MR ), maximum T MR , full width half maximum (FWHM), and other descriptors of tumors and normal tissues were noninvasively derived and their dependencies outlined. In 8 of 15 patients, direct temperature measurements in reference points were available. We correlated the tumor MR temperatures with direct measurements, clinical response, and tumor features (volume and location), and found reasonable trends and correlations. Therefore, the mean T MR of the tumor might be useful as a variable to evaluate the quality and effectivity of heat treatments, and consequently as optimization variable. Feasibility of noninvasive MR thermography for regional hyperthermia has been shown and should be further investigated. (Cancer Res 2005; 65(13): 5872-80)

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“…Temperature-induced susceptibility changes due to perfusion and potentially associated blood oxygenation also could hamper the accuracy of temperature measurements (23). According to measurements performed by de Poorter (24), the slope (0.16 * 10 -8 /°C) of the volume susceptibility constant of muscle tissue is small compared to that (0.97 * 10 -8 /°C) of the screening constant of muscle.…”

Section: Systematic Temperature Uncertaintymentioning

confidence: 99%

Temperature quantification using the proton frequency shift technique: In vitro and in vivo validation in an open 0.5 tesla interventional MR scanner during RF ablation

Botnar

Steiner

Dubno

et al. 2001

J. Magn. Reson. Imaging

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Index terms: temperature mapping; proton frequency shift; RF thermal ablation; interventional MR; medical instrumentation MINIMALLY INVASIVE PERCUTANEOUS thermoablation techniques, such as radio frequency (RF) ablation, have shown promise in the treatment of deep-seated tumors in the human body (1,2). Compared to conventional surgical interventions, these techniques can reduce overall morbidity and shorten patient recovery times, thereby decreasing health-care costs. Temperature sensitivity inherent to MR experiments provides the basis for using magnetic resonance imaging (MRI) to monitor thermosensitive therapies. Several temperature-dependent MR parameters, such as the spin-lattice relaxation time T1 (3-5), the molecular diffusion coefficient (6,7), or the proton frequency shift (PFS) (8 -10) can be exploited for the purpose of MR temperature mapping.Fast T1-weighted sequences have been used to monitor local heating of various organs (5,11,12). However, T1 temperature dependency varies in different tissues and is influenced by thermoregulative processes and metabolic tissue changes. Hence, temperature changes cannot be reliably quantified. Diffusion-weighted imaging is based on the thermal Brownian motion, which is described by the diffusion coefficient. The drawback of this method lies in long data acquisition times. If applied in vivo, it suffers from thermoregulative diffusion changes and from tissue motion. The PFS technique takes advantage of the temperature-dependent phase shift of the MR signal (8 -10). PFS has very small tissue dependency of the chemical shift compared to the T1 relaxation time and relatively short acquisition time compared to the diffusion technique. PFS temperature sensitivity is related to changes of the molecular screening constant. A disadvantage of the PFS technique lies in its sensitivity to motion artifacts and frequency drifts induced by system instabilities. While motion artifacts can be reduced to some extent by breath holding, system imperfections may induce a phase offset, which can be reduced by suitable correction schemes.The availability of 0.5 T open-configuration systems, in conjunction with optical tracking systems for realtime instrument guidance in an MR environment (15,16), allows for easy placement and interactive positional adjustment of thermal therapy applicators in various organs. For clinically effective monitoring, MR temperature maps need to be acquired in near real time with sufficient spatial and contrast resolution. Furthermore, reliable temperature control must be tissue independent and provide quantitative temperature data.The purpose of this work was to validate the PFS technique for quantitative temperature mapping in an

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An evaluation of the effects of susceptibility changes on the water chemical shift method of temperature measurement in human peripheral muscle

Cited by 62 publications

References 16 publications

MR thermometry

MR thermometry

Noninvasive Magnetic Resonance Thermography of Recurrent Rectal Carcinoma in a 1.5 Tesla Hybrid System

Temperature quantification using the proton frequency shift technique: In vitro and in vivo validation in an open 0.5 tesla interventional MR scanner during RF ablation

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