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Kim K, Narsinh K, Ozhinsky E. Technical advances in motion-robust MR thermometry. Magn Reson Med 2024; 92:15-27. [PMID: 38501903 DOI: 10.1002/mrm.30057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 01/25/2024] [Accepted: 01/27/2024] [Indexed: 03/20/2024]
Abstract
Proton resonance frequency shift (PRFS) MR thermometry is the most common method used in clinical thermal treatments because of its fast acquisition and high sensitivity to temperature. However, motion is the biggest obstacle in PRFS MR thermometry for monitoring thermal treatment in moving organs. This challenge arises because of the introduction of phase errors into the PRFS calculation through multiple methods, such as image misregistration, susceptibility changes in the magnetic field, and intraframe motion during MRI acquisition. Various approaches for motion correction have been developed for real-time, motion-robust, and volumetric MR thermometry. However, current technologies have inherent trade-offs among volume coverage, processing time, and temperature accuracy. These tradeoffs should be considered and chosen according to the thermal treatment application. In hyperthermia treatment, precise temperature measurements are of increased importance rather than the requirement for exceedingly high temporal resolution. In contrast, ablation procedures require robust temporal resolution to accurately capture a rapid temperature rise. This paper presents a comprehensive review of current cutting-edge MRI techniques for motion-robust MR thermometry, and recommends which techniques are better suited for each thermal treatment. We expect that this study will help discern the selection of motion-robust MR thermometry strategies and inspire the development of motion-robust volumetric MR thermometry for practical use in clinics.
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Affiliation(s)
- Kisoo Kim
- Department of Radiology & Biomedical Imaging, University of California, San Francisco, California, USA
| | - Kazim Narsinh
- Department of Radiology & Biomedical Imaging, University of California, San Francisco, California, USA
| | - Eugene Ozhinsky
- Department of Radiology & Biomedical Imaging, University of California, San Francisco, California, USA
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2
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Kim S, Kim D, Oh S. Straightforward Magnetic Resonance Temperature Measurements Combined with High Frame Rate and Magnetic Susceptibility Correction. Bioengineering (Basel) 2023; 10:1299. [PMID: 38002423 PMCID: PMC10669085 DOI: 10.3390/bioengineering10111299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 10/10/2023] [Accepted: 11/03/2023] [Indexed: 11/26/2023] Open
Abstract
Proton resonance frequency shift (PRFS) is an MRI-based simple temperature mapping method that exhibits higher spatial and temporal resolution than temperature mapping methods based on T1 relaxation time and diffusion. PRFS temperature measurements are validated against fiber-optic thermal sensors (FOSs). However, the use of FOSs may introduce temperature errors, leading to both underestimation and overestimation of PRFS measurements, primarily due to material susceptibility changes caused by the thermal sensors. In this study, we demonstrated susceptibility-corrected PRFS (scPRFS) with a high frame rate and accuracy for suitably distributed temperatures. A single-echo-based background removal technique was employed for phase variation correction, primarily owing to magnetic susceptibility, which enabled fast temperature mapping. The scPRFS was used to validate the temperature fidelity by comparing the temperatures of fiber-optic sensors and conventional PRFS through phantom-mimicked human and ex vivo experiments. This study demonstrates that scPRFS measurements in agar-gel are in good agreement with the thermal sensor readings, with a root mean square error (RMSE) of 0.33-0.36 °C in the phantom model and 0.12-0.16 °C in the ex vivo experiment. These results highlight the potential of scPRFS for precise thermal monitoring and ablation in both low- and high-temperature non-invasive therapies.
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Affiliation(s)
- Sangwoo Kim
- Department of Radiological Science, Daewon University College, Jecheon 27135, Republic of Korea
| | - Donghyuk Kim
- Neuroscience Research Institute, Gachon University, Incheon 21988, Republic of Korea
| | - Sukhoon Oh
- Center for Research Equipment, Korea Basic Science Institute, Cheongju 28119, Republic of Korea
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Odéen H, Hofstetter LW, Payne AH, Guiraud L, Dumont E, Parker DL. Simultaneous proton resonance frequency T 1 - MR shear wave elastography for MR-guided focused ultrasound multiparametric treatment monitoring. Magn Reson Med 2023; 89:2171-2185. [PMID: 36656135 PMCID: PMC10940047 DOI: 10.1002/mrm.29587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 12/21/2022] [Accepted: 12/30/2022] [Indexed: 01/20/2023]
Abstract
PURPOSE To develop an efficient MRI pulse sequence to simultaneously measure multiple parameters that have been shown to correlate with tissue nonviability following thermal therapies. METHODS A 3D segmented EPI pulse sequence was used to simultaneously measure proton resonance frequency shift (PRFS) MR thermometry (MRT), T1 relaxation time, and shear wave velocity induced by focused ultrasound (FUS) push pulses. Experiments were performed in tissue mimicking gelatin phantoms and ex vivo bovine liver. Using a carefully designed FUS triggering scheme, a heating duty cycle of approximately 65% was achieved by interleaving FUS ablation pulses with FUS push pulses to induce shear waves in the tissue. RESULTS In phantom studies, temperature increases measured with PRFS MRT and increases in T1 correlated with decreased shear wave velocity, consistent with material softening with increasing temperature. During ablation in ex vivo liver, temperature increase measured with PRFS MRT initially correlated with increasing T1 and decreasing shear wave velocity, and after tissue coagulation with decreasing T1 and increasing shear wave velocity. This is consistent with a previously described hysteresis in T1 versus PRFS curves and increased tissue stiffness with tissue coagulation. CONCLUSION An efficient approach for simultaneous and dynamic measurements of PRSF, T1 , and shear wave velocity during treatment is presented. This approach holds promise for providing co-registered dynamic measures of multiple parameters, which correlates to tissue nonviability during and following thermal therapies, such as FUS.
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Affiliation(s)
- Henrik Odéen
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Lorne W. Hofstetter
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Allison H. Payne
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA
| | | | | | - Dennis L. Parker
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA
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Kim K, Ahn J, Yoon K, Ko M, Ahn J, Kim H, Park J, Lee C, Chang D, Oh S. In Vivo Magnetic Resonance Thermometry for Brain and Body Temperature Variations in Canines under General Anesthesia. Sensors (Basel) 2022; 22:s22114034. [PMID: 35684654 PMCID: PMC9183176 DOI: 10.3390/s22114034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/22/2022] [Accepted: 05/24/2022] [Indexed: 02/06/2023]
Abstract
The core body temperature tends to decrease under general anesthesia. Consequently, monitoring the core body temperature during procedures involving general anesthesia is essential to ensure patient safety. In veterinary medicine, rectal temperature is used as an indicator of the core body temperature, owing to the accuracy and convenience of this approach. Some previous studies involving craniotomy reported differences between the brain and core temperatures under general anesthesia. However, noninvasive imaging techniques are required to ascertain this because invasive brain temperature measurements can cause unintended temperature changes by inserting the temperature sensors into the brain or by performing the surgical operations. In this study, we employed in vivo magnetic resonance thermometry to observe the brain temperatures of patients under general anesthesia using the proton resonance frequency shift method. The rectal temperature was also recorded using a fiber optic thermometer during the MR thermometry to compare with the brain temperature changes. When the rectal temperature decreased by 1.4 ± 0.5 °C (mean ± standard deviation), the brain temperature (white matter) decreased by 4.8 ± 0.5 °C. Furthermore, a difference in the temperature reduction of the different types of brain tissue was observed; the reduction in the temperature of white matter exceeded that of gray matter mainly due to the distribution of blood vessels in the gray matter. We also analyzed and interpreted the core temperature changes with the body conditioning scores of subjects to see how the body weight affected the temperature changes.
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Affiliation(s)
- Keonil Kim
- Bio-Chemical Analysis Team, Center for Research Equipment, Korea Basic Science Institute, Cheongju 28119, Korea; (K.K.); (C.L.)
- Department of Bio-Analytical Science, University of Science and Technology, Daejeon 34113, Korea
| | - Jisoo Ahn
- Section of Veterinary Medical Imaging, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea; (J.A.); (K.Y.); (M.K.); (J.A.); (H.K.); (J.P.)
| | - Kwangyong Yoon
- Section of Veterinary Medical Imaging, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea; (J.A.); (K.Y.); (M.K.); (J.A.); (H.K.); (J.P.)
| | - Minjung Ko
- Section of Veterinary Medical Imaging, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea; (J.A.); (K.Y.); (M.K.); (J.A.); (H.K.); (J.P.)
| | - Jiyoung Ahn
- Section of Veterinary Medical Imaging, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea; (J.A.); (K.Y.); (M.K.); (J.A.); (H.K.); (J.P.)
| | - Hyesung Kim
- Section of Veterinary Medical Imaging, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea; (J.A.); (K.Y.); (M.K.); (J.A.); (H.K.); (J.P.)
| | - Jihyeon Park
- Section of Veterinary Medical Imaging, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea; (J.A.); (K.Y.); (M.K.); (J.A.); (H.K.); (J.P.)
| | - Chulhyun Lee
- Bio-Chemical Analysis Team, Center for Research Equipment, Korea Basic Science Institute, Cheongju 28119, Korea; (K.K.); (C.L.)
- Department of Bio-Analytical Science, University of Science and Technology, Daejeon 34113, Korea
| | - Dongwoo Chang
- Section of Veterinary Medical Imaging, College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Korea; (J.A.); (K.Y.); (M.K.); (J.A.); (H.K.); (J.P.)
- Correspondence: (D.C.); (S.O.)
| | - Sukhoon Oh
- Bio-Chemical Analysis Team, Center for Research Equipment, Korea Basic Science Institute, Cheongju 28119, Korea; (K.K.); (C.L.)
- Correspondence: (D.C.); (S.O.)
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Boehm C, Goeger-Neff M, Mulder HT, Zilles B, Lindner LH, van Rhoon GC, Karampinos DC, Wu M. Susceptibility artifact correction in MR thermometry for monitoring of mild radiofrequency hyperthermia using total field inversion. Magn Reson Med 2022; 88:120-132. [PMID: 35313384 DOI: 10.1002/mrm.29191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 01/19/2022] [Accepted: 01/20/2022] [Indexed: 12/28/2022]
Abstract
PURPOSE MR temperature monitoring of mild radiofrequency hyperthermia (RF-HT) of cancer exploits the linear resonance frequency shift of water with temperature. Motion-induced susceptibility distribution changes cause artifacts that we correct here using the total field inversion (TFI) approach. METHODS The performance of TFI was compared to two background field removal (BFR) methods: Laplacian boundary value (LBV) and projection onto dipole fields (PDF). Data sets with spatial susceptibility change and B 0 -drift were simulated, phantom heating experiments were performed, four volunteer data sets at thermoneutral conditions as well as data from one cervical cancer, two sarcoma, and one seroma patients undergoing mild RF-HT were corrected using the proposed methods. RESULTS Simulations and phantom heating experiments revealed that using BFR or TFI preserves temperature-induced phase change, while removing susceptibility artifacts and B 0 -drift. TFI resulted in the least cumulative error for all four volunteers. Temperature probe information from four patient data sets were best depicted by TFI-corrected data in terms of accuracy and precision. TFI also performed best in case of the sarcoma treatment without temperature probe. CONCLUSION TFI outperforms previously suggested BFR methods in terms of accuracy and robustness. While PDF consistently overestimates susceptibility contribution, and LBV removes valuable pixel information, TFI is more robust and leads to more accurate temperature estimations.
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Affiliation(s)
- Christof Boehm
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany
| | | | | | - Benjamin Zilles
- Department of Medicine III, University Hospital, LMU Munich, Munich, Germany
| | - Lars H Lindner
- Department of Medicine III, University Hospital, LMU Munich, Munich, Germany
| | | | - Dimitrios C Karampinos
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany
| | - Mingming Wu
- Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany
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Militello C, Rundo L, Vicari F, Agnello L, Borasi G, Vitabile S, Russo G. A Computational Study on Temperature Variations in MRgFUS Treatments Using PRF Thermometry Techniques and Optical Probes. J Imaging 2021; 7:63. [PMID: 34460513 PMCID: PMC8321332 DOI: 10.3390/jimaging7040063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/16/2021] [Accepted: 03/23/2021] [Indexed: 12/18/2022] Open
Abstract
Structural and metabolic imaging are fundamental for diagnosis, treatment and follow-up in oncology. Beyond the well-established diagnostic imaging applications, ultrasounds are currently emerging in the clinical practice as a noninvasive technology for therapy. Indeed, the sound waves can be used to increase the temperature inside the target solid tumors, leading to apoptosis or necrosis of neoplastic tissues. The Magnetic resonance-guided focused ultrasound surgery (MRgFUS) technology represents a valid application of this ultrasound property, mainly used in oncology and neurology. In this paper; patient safety during MRgFUS treatments was investigated by a series of experiments in a tissue-mimicking phantom and performing ex vivo skin samples, to promptly identify unwanted temperature rises. The acquired MR images, used to evaluate the temperature in the treated areas, were analyzed to compare classical proton resonance frequency (PRF) shift techniques and referenceless thermometry methods to accurately assess the temperature variations. We exploited radial basis function (RBF) neural networks for referenceless thermometry and compared the results against interferometric optical fiber measurements. The experimental measurements were obtained using a set of interferometric optical fibers aimed at quantifying temperature variations directly in the sonication areas. The temperature increases during the treatment were not accurately detected by MRI-based referenceless thermometry methods, and more sensitive measurement systems, such as optical fibers, would be required. In-depth studies about these aspects are needed to monitor temperature and improve safety during MRgFUS treatments.
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Affiliation(s)
- Carmelo Militello
- Institute of Molecular Bioimaging and Physiology, Italian National Research Council (IBFM-CNR), Cefalu, 90015 Palermo, Italy;
| | - Leonardo Rundo
- Department of Radiology, University of Cambridge, Cambridge CB2 0QQ, UK;
- Cancer Research UK Cambridge Centre, Cambridge CB2 0RE, UK
| | - Fabrizio Vicari
- LAboratorio di Tecnologie Oncologiche (LATO), Cefalu, 90015 Palermo, Italy; (F.V.); (G.B.)
| | - Luca Agnello
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (BiND), University of Palermo, 90127 Palermo, Italy; (L.A.); (S.V.)
| | - Giovanni Borasi
- LAboratorio di Tecnologie Oncologiche (LATO), Cefalu, 90015 Palermo, Italy; (F.V.); (G.B.)
| | - Salvatore Vitabile
- Department of Biomedicine, Neuroscience and Advanced Diagnostics (BiND), University of Palermo, 90127 Palermo, Italy; (L.A.); (S.V.)
| | - Giorgio Russo
- Institute of Molecular Bioimaging and Physiology, Italian National Research Council (IBFM-CNR), Cefalu, 90015 Palermo, Italy;
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Blackwell J, Kraśny MJ, O'Brien A, Ashkan K, Galligan J, Destrade M, Colgan N. Proton Resonance Frequency Shift Thermometry: A Review of Modern Clinical Practices. J Magn Reson Imaging 2020; 55:389-403. [PMID: 33217099 DOI: 10.1002/jmri.27446] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/02/2020] [Accepted: 11/02/2020] [Indexed: 12/22/2022] Open
Abstract
Magnetic resonance imaging (MRI) has become a popular modality in guiding minimally invasive thermal therapies, due to its advanced, nonionizing, imaging capabilities and its ability to record changes in temperature. A variety of MR thermometry techniques have been developed over the years, and proton resonance frequency (PRF) shift thermometry is the current clinical gold standard to treat a variety of cancers. It is used extensively to guide hyperthermic thermal ablation techniques such as high-intensity focused ultrasound (HIFU) and laser-induced thermal therapy (LITT). Essential attributes of PRF shift thermometry include excellent linearity with temperature, good sensitivity, and independence from tissue type. This noninvasive temperature mapping method gives accurate quantitative measures of the temperature evolution inside biological tissues. In this review, the current status and new developments in the fields of MR-guided HIFU and LITT are presented with an emphasis on breast, prostate, bone, uterine, and brain treatments. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.
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Affiliation(s)
- James Blackwell
- Advanced Biological Imaging Laboratory, School of Physics, National University of Ireland Galway, Galway, Ireland.,School of Mathematics, Statistics and Applied Mathematics, National University of Ireland Galway, Galway, Ireland
| | - Marcin J Kraśny
- Advanced Biological Imaging Laboratory, School of Physics, National University of Ireland Galway, Galway, Ireland
| | - Aoife O'Brien
- School of Psychology, National University of Ireland Galway, Galway, Ireland
| | - Keyoumars Ashkan
- Neurosurgical Department, King's College Hospital Foundation Trust, London, UK.,Harley Street Clinic, London Neurosurgery Partnership, London, UK
| | - Josette Galligan
- Department of Medical Physics and Bioengineering, St. James' Hospital, Dublin, Ireland
| | - Michel Destrade
- School of Mathematics, Statistics and Applied Mathematics, National University of Ireland Galway, Galway, Ireland
| | - Niall Colgan
- Advanced Biological Imaging Laboratory, School of Physics, National University of Ireland Galway, Galway, Ireland
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Le Ster C, Mauconduit F, Mirkes C, Bottlaender M, Boumezbeur F, Djemai B, Vignaud A, Boulant N. RF heating measurement using MR thermometry and field monitoring: Methodological considerations and first in vivo results. Magn Reson Med 2020; 85:1282-1293. [PMID: 32936510 DOI: 10.1002/mrm.28501] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/10/2020] [Accepted: 08/10/2020] [Indexed: 11/11/2022]
Abstract
PURPOSE A MR thermometry (MRT) method with field monitoring is proposed to improve the measurement of small temperature variations induced in brain MRI exams. METHODS MR thermometry experiments were performed at 7 Tesla with concurrent field monitoring and RF heating. Images were reconstructed with nominal k-space trajectories and with first-order spherical harmonics correction. Experiments were performed in vitro with deliberate field disturbances and on an anesthetized macaque in 2 different specific absorption rate regimes, that is, at 50% and 100% of the maximal specific absorption rate level allowed in the International Electrotechnical Commission normal mode of operation. Repeatability was assessed by running a second separate session on the same animal. RESULTS Inclusion of magnetic field fluctuations in the reconstruction improved temperature measurement accuracy in vitro down to 0.02°C. Measurement precision in vivo was on the order of 0.15°C in areas little affected by motion. In the same region, temperature increase reached 0.5 to 0.8°C after 20 min of heating at 100% specific absorption rates and followed a rough factor of 2 with the 50% specific absorption rate scans. A horizontal temperature plateau, as predicted by Pennes bioheat model with thermal constants from the literature and constant blood temperature assumption, was not observed. CONCLUSION Inclusion of field fluctuations in image reconstruction was beneficial for the measurement of small temperature rises encountered in standard brain exams. More work is needed to correct for motion-induced field disturbances to extract reliable temperature maps.
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Affiliation(s)
- Caroline Le Ster
- Université Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, Gif-sur-Yvette, France
| | - Franck Mauconduit
- Université Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, Gif-sur-Yvette, France
| | | | - Michel Bottlaender
- Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Service Hospitalier Frederic Joliot, Orsay, France.,UNIACT, Neurospin, CEA, Gif-sur-Yvette, France
| | - Fawzi Boumezbeur
- Université Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, Gif-sur-Yvette, France
| | - Boucif Djemai
- Université Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, Gif-sur-Yvette, France
| | - Alexandre Vignaud
- Université Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, Gif-sur-Yvette, France
| | - Nicolas Boulant
- Université Paris-Saclay, CEA, CNRS, BAOBAB, NeuroSpin, Gif-sur-Yvette, France
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Ozenne V, Bour P, de Senneville BD, Toupin S, Vaussy A, Lepetit-Coiffé M, Jaïs P, Cochet H, Quesson B. Assessment of left ventricle magnetic resonance temperature stability in patients in the presence of arrhythmias. NMR Biomed 2019; 32:e4160. [PMID: 31397942 DOI: 10.1002/nbm.4160] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND Magnetic resonance (MR) thermometry allows visualization of lesion formation in real-time during cardiac radiofrequency (RF) ablation. The present study was performed to evaluate the precision of MR thermometry without RF heating in patients exhibiting cardiac arrhythmia in a clinical setting. The evaluation relied on quantification of changes in temperature measurements caused by noise and physiological motion. METHODS Fourteen patients referred for cardiovascular magnetic resonance imaging underwent an extra sequence to test the temperature mapping stability during free-breathing acquisition. Phase images were acquired using a multi-slice, cardiac-triggered, single-shot echo planar imaging sequence. Temperature maps were calculated and displayed in real-time while the electrocardiogram (ECG) was recorded. The precision of temperature measurement was assessed by measuring the temporal standard deviation and temporal mean of consecutive temperature maps over a period of three minutes. The cardiac cycle was analyzed from ECG recordings to quantify the impact of arrhythmia events on the precision of temperature measurement. Finally, two retrospective strategies were tested to remove acquisition dynamics related either to arrhythmia events or sudden breathing motion. RESULTS ECG synchronization allowed categorization of inter-beat intervals (RR) into distinct beat morphologies. Five patients were in stable sinus rhythm, while nine patients showed irregular RR intervals due to ectopic beats. An average temporal standard deviation of temperature of 1.6°C was observed in patients under sinus rhythm with a frame rate corresponding to the heart rate of the patient. The temporal standard deviation rose to 2.5°C in patients with arrhythmia. The retrospective rejection strategies increased the temperature precision measurement while maintaining a sufficient frame rate. CONCLUSIONS Our results indicated that real-time cardiac MR thermometry shows good precision in patients under clinical conditions, even in the presence of arrhythmia. By providing real-time visualization of temperature distribution within the myocardium during RF delivery, MR thermometry could prevent insufficient or excessive heating and thus improve safety and efficacy.
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Affiliation(s)
- Valéry Ozenne
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France
- Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
- INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | - Pierre Bour
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France
- Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
- INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | | | - Solenn Toupin
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France
- Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
- INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
- Siemens Healthcare France, Saint Denis, France
| | - Alexis Vaussy
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France
- Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
- INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
- Siemens Healthcare France, Saint Denis, France
| | | | - Pierre Jaïs
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France
- Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France
| | - Hubert Cochet
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France
- Centre Hospitalier Universitaire de Bordeaux, Bordeaux, France
| | - Bruno Quesson
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Bordeaux, France
- Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
- INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
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Abstract
OBJECTIVES To develop, test and evaluate improved 2D and 3D protocols for proton resonance frequency shift magnetic resonance temperature imaging (MRTI) of laser interstitial thermal therapy (LITT). The objective was to develop improved MRTI protocols in terms of temperature measurement precision and volume coverage compared to the 2D MRTI protocol currently used with a commercially available LITT system. METHODS Four different 2D protocols and four different 3D protocols were investigated. The 2D protocols used multi-echo readouts to prolong the total MR sampling time and hence the MRTI precision, without prolonging the total acquisition time. The 3D protocols provided volumetric thermometry by acquiring a slab of 12 contiguous slices in the same acquisition time as the 2D protocols. The study only considered readily available pulse sequences (Cartesian 2D and 3D gradient recalled echo and echo planar imaging [EPI]) and methods (partial Fourier and parallel imaging) to ensure wide availability and rapid clinical implementation across vendors and field strengths. In vivo volunteer studies were performed to investigate and compare MRTI precision and image quality. Phantom experiments with LITT heating were performed to investigate and compare MRTI precision and accuracy. Different coil setups were used in the in vivo studies to assess precision differences between using local (such as flex and head coils) and non-local (i.e., body coil) receive coils. Studies were performed at both 1.5 T and 3 T. RESULTS The improved 2D protocols provide up to a factor of two improvement in the MRTI precision in the same acquisition time, compared to the currently used clinical protocol. The 3D echo planar imaging protocols provide comparable precision as the currently used 2D clinical protocol, but over a substantially larger field of view, without increasing the acquisition time. As expected, local receive coils perform substantially better than the body coil, and 3 T provides better MRTI accuracy and precision than 1.5 T. 3D data can be zero-filled interpolated in all three dimensions (as opposed to just two dimensions for 2D data), reducing partial volume effects and measuring higher maximum temperature rises. CONCLUSIONS With the presented protocols substantially improved MRTI precision (for 2D imaging) or greatly improved field of view coverage (for 3D imaging) can be achieved in the same acquisition time as the currently used protocol. Only widely available pulse sequences and acquisition methods were investigated, which should ensure quick translation to the clinic. Lasers Surg. Med. 51:286-300, 2019. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Henrik Odéen
- Utah Center for Advanced Imaging Research, Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah
| | - Dennis L Parker
- Utah Center for Advanced Imaging Research, Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah
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11
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Poorman ME, Braškutė I, Bartels LW, Grissom WA. Multi-echo MR thermometry using iterative separation of baseline water and fat images. Magn Reson Med 2018; 81:2385-2398. [PMID: 30394582 DOI: 10.1002/mrm.27567] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 09/20/2018] [Accepted: 09/21/2018] [Indexed: 12/17/2022]
Abstract
PURPOSE To perform multi-echo water/fat separated proton resonance frequency (PRF)-shift temperature mapping. METHODS State-of-the-art, iterative multi-echo water/fat separation algorithms produce high-quality water and fat images in the absence of heating but are not suitable for real-time imaging due to their long compute times and potential errors in heated regions. Existing fat-referenced PRF-shift temperature reconstruction methods partially address these limitations but do not address motion or large time-varying and spatially inhomogeneous B0 shifts. We describe a model-based temperature reconstruction method that overcomes these limitations by fitting a library of separated water and fat images measured before heating directly to multi-echo data measured during heating, while accounting for the PRF shift with temperature. RESULTS Simulations in a mixed water/fat phantom with focal heating showed that the proposed algorithm reconstructed more accurate temperature maps in mixed tissues compared to a fat-referenced thermometry method. In a porcine phantom experiment with focused ultrasound heating at 1.5 Tesla, temperature maps were accurate to within 1∘ C of fiber optic probe temperature measurements and were calculated in 0.47 s per time point. Free-breathing breast and liver imaging experiments demonstrated motion and off-resonance compensation. The algorithm can also accurately reconstruct water/fat separated temperature maps from a single echo during heating. CONCLUSIONS The proposed model-based water/fat separated algorithm produces accurate PRF-shift temperature maps in mixed water and fat tissues in the presence of spatiotemporally varying off-resonance and motion.
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Affiliation(s)
- Megan E Poorman
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Ieva Braškutė
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands
| | - Lambertus W Bartels
- Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands
| | - William A Grissom
- Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
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12
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Cheng C, Zou C, Wan Q, Qiao Y, Pan M, Tie C, Liang D, Zheng H, Liu X. Dual-step iterative temperature estimation method for accurate and precise fat-referenced PRFS temperature imaging. Magn Reson Med 2018; 81:1322-1334. [PMID: 30230595 DOI: 10.1002/mrm.27396] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2018] [Revised: 05/15/2018] [Accepted: 05/19/2018] [Indexed: 12/24/2022]
Abstract
PURPOSE The aim of this study was to propose dual-step iterative temperature estimation (DITE) of a fat-referenced proton resonance frequency shift (PRFS) method to improve both the accuracy and precision of temperature estimations in fat-containing tissues. METHODS A fat-water signal model with multiple fat peaks was used to simultaneously estimate the temperature, fat/water intensity and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mtext>T</mml:mtext> <mml:mrow><mml:mn>2</mml:mn></mml:mrow> <mml:mrow><mml:mrow/> <mml:mo>∗</mml:mo></mml:mrow> </mml:msubsup> </mml:math> , and field offset. In DITE, model fitting was implemented with alternating 2-step minimizations. The estimated temperature map was smoothed between the 2-step minimizations, which is considered to be the most important step for improving the temperature precision. The performance of DITE was evaluated with a Monte Carlo simulation, fat/water phantoms, and ex vivo brown adipose tissue experiments and then compared with the performance of previous fat-referenced proton resonance frequency shift methods. RESULTS In fat/water phantom experiment with a smooth temperature profile, the temperatures estimated by DITE are consistent with the thermometer results and present a better accuracy and precision than those of previous fat-referenced proton resonance frequency shift methods. In the brown adipose tissue heating experiment, the average mean error, SD, and RMS error were -0.08ºC, 0.46ºC, and 0.56ºC, respectively, over all of the measurements within the region of interest. CONCLUSION Our proposed DITE method improves both the accuracy and precision of temperature measurements in tissues with fat fractions between 20% and 80% under smooth distribution of the temperature profile and represents a simple fat-referenced thermometry method.
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Affiliation(s)
- Chuanli Cheng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Shenzhen, China
| | - Chao Zou
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Shenzhen, China
| | - Qian Wan
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Shenzhen College of Advanced Technology, University of Chinese Academy of Sciences, Shenzhen, China
| | - Yangzi Qiao
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Min Pan
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Shenzhen Hospital of Guangzhou University of Chinese Medicine, Shenzhen, China
| | - Changjun Tie
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Dong Liang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Hairong Zheng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Chongqing Collaborative Innovation Center for Minimally Invasive and Noninvasive Medicine, Chongqing, China
| | - Xin Liu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Chongqing Collaborative Innovation Center for Minimally Invasive and Noninvasive Medicine, Chongqing, China
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13
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Chen Y, Ge M, Jiang H, Wang L, Qiu B. An effective method for monitoring tissue temperature using low-field MRI system. Technol Health Care 2018; 26:565-570. [PMID: 29630573 DOI: 10.3233/thc-181236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This technical note describes an effective method for monitoring temperature based on the minimum curvature surface fitting (MCSF) referenceless proton resonance frequency shift (PRFs) at 0.35 T. Experimental tests on phantom, ex vivo porcine livers and human brain were conducted. A comparison study between the proposed method and a fiber optic temperature probe was conducted for microwave (MW) ablation. Experimental results showed that temperature root mean square error (RMSE) calculated by MCSF model were lower than those computed by high-order polynomial fitting. For ablation experiments, the temperature errors between temperature probe and MCSF method were all less than 2∘C.
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Affiliation(s)
- Yuping Chen
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Mengke Ge
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Hejun Jiang
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
| | - Lulu Wang
- School of Instrument Science and Opto-Electronics Engineering, Hefei University of Technology, Hefei, Anhui, China
| | - Bensheng Qiu
- Centers for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui, China
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14
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Weber H, Ghanouni P, Pascal-Tenorio A, Pauly KB, Hargreaves BA. MRI monitoring of focused ultrasound sonications near metallic hardware. Magn Reson Med 2017; 80:259-271. [PMID: 29215150 DOI: 10.1002/mrm.27034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 01/06/2023]
Abstract
PURPOSE To explore the temperature-induced signal change in two-dimensional multi-spectral imaging (2DMSI) for fast thermometry near metallic hardware to enable MR-guided focused ultrasound surgery (MRgFUS) in patients with implanted metallic hardware. METHOD 2DMSI was optimized for temperature sensitivity and applied to monitor focus ultrasound surgery (FUS) sonications near metallic hardware in phantoms and ex vivo porcine muscle tissue. Further, we evaluated its temperature sensitivity for in vivo muscle in patients without metallic hardware. In addition, we performed a comparison of temperature sensitivity between 2DMSI and conventional proton-resonance-frequency-shift (PRFS) thermometry at different distances from metal devices and different signal-to-noise ratios (SNR). RESULTS 2DMSI thermometry enabled visualization of short ultrasound sonications near metallic hardware. Calibration using in vivo muscle yielded a constant temperature sensitivity for temperatures below 43 °C. For an off-resonance coverage of ± 6 kHz, we achieved a temperature sensitivity of 1.45%/K, resulting in a minimum detectable temperature change of ∼2.5 K for an SNR of 100 with a temporal resolution of 6 s per frame. CONCLUSION The proposed 2DMSI thermometry has the potential to allow MR-guided FUS treatments of patients with metallic hardware and therefore expand its reach to a larger patient population. Magn Reson Med 80:259-271, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Hans Weber
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Pejman Ghanouni
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | | | - Kim Butts Pauly
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Brian A Hargreaves
- Department of Radiology, Stanford University, Palo Alto, California, USA
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15
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Zhang L, Burant A, McCallister A, Zhao V, Koshlap KM, Degan S, Antonacci M, Branca RT. Accurate MR thermometry by hyperpolarized 129 Xe. Magn Reson Med 2016; 78:1070-1079. [PMID: 27759913 DOI: 10.1002/mrm.26506] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/14/2016] [Accepted: 09/19/2016] [Indexed: 12/31/2022]
Abstract
PURPOSE To investigate the temperature dependence of the resonance frequency of lipid-dissolved xenon (LDX) and to assess the accuracy of LDX-based MR thermometry. METHODS The chemical shift temperature dependence of water protons, methylene protons, and LDX was measured from samples containing tissues with varying fat contents using a high-resolution NMR spectrometer. LDX results were then used to acquire relative and absolute temperature maps in vivo and the results were compared with PRF-based MR thermometry. RESULTS The temperature dependence of proton resonance frequency (PRF) is strongly affected by the specific distribution of water and fat. A redistribution of water and fat compartments can reduce the apparent temperature dependence of the water chemical shift from -0.01 ppm/°C to -0.006 ppm, whereas the LDX chemical shift shows a consistent temperature dependence of -0.21 ppm/°C. The use of the methylene protons resonance frequency as internal reference improves the accuracy of LDX-based MR thermometry, but degrades that of PRF-based MR thermometry, as microscopic susceptibility gradients affected lipid and water spins differently. CONCLUSION The LDX resonance frequency, with its higher temperature dependence, provides more accurate and precise temperature measurements, both in vitro and in vivo. More importantly, the resonance frequency of nearby methylene protons can be used to extract absolute temperature information. Magn Reson Med 78:1070-1079, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Le Zhang
- Department of Applied Physical Science, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Alex Burant
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Andrew McCallister
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Victor Zhao
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Karl M Koshlap
- Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Simone Degan
- Center for Molecular and Biomolecular Imaging, Department of Radiology and Dermatology, Duke University, Durham, North Carolina, USA
| | - Michael Antonacci
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Rosa Tamara Branca
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.,Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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16
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Weber H, Taviani V, Yoon D, Ghanouni P, Pauly KB, Hargreaves BA. MR thermometry near metallic devices using multispectral imaging. Magn Reson Med 2016; 77:1162-1169. [PMID: 26991803 DOI: 10.1002/mrm.26203] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/27/2016] [Accepted: 02/16/2016] [Indexed: 11/07/2022]
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.
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Affiliation(s)
- Hans Weber
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Valentina Taviani
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Daehyun Yoon
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Pejman Ghanouni
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Kim Butts Pauly
- Department of Radiology, Stanford University, Palo Alto, California, USA
| | - Brian A Hargreaves
- Department of Radiology, Stanford University, Palo Alto, California, USA
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17
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Ciris PA, Cheng CC, Mei CS, Panych LP, Madore B. Dual-Pathway sequences for MR thermometry: When and where to use them. Magn Reson Med 2016; 77:1193-1200. [PMID: 26968318 DOI: 10.1002/mrm.26177] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 01/21/2016] [Accepted: 01/31/2016] [Indexed: 01/23/2023]
Abstract
PURPOSE Dual-pathway sequences have been proposed to help improve the temperature-to-noise ratio (TNR) in MR thermometry. The present work establishes how much of an improvement these so-called "PSIF-FISP" sequences may bring in various organs and tissues. METHODS Simulations and TNR calculations were validated against analytical equations, phantom, abdomen, and brain scans. Relative TNRs for PSIF-FISP, as compared to a dual-FISP reference standard, were calculated for flip angle (FA) = 1 to 85 º and repetition time (TR) = 6 to 60 ms, for gray matter, white matter, cervix, endometrium, myometrium, prostate, kidney medulla and cortex, bone marrow, pancreas, spleen, muscle, and liver tissues. RESULTS PSIF-FISP was TNR superior in the kidney, pelvis, spleen, or gray matter at most tested TR and FA settings, and benefits increased at shorter TRs. PSIF-FISP was TNR superior in other tissues, e.g., liver, muscle, pancreas, for only short TR settings (20 ms or less). The TNR benefits of PSIF-FISP increased slightly with FA, and strongly with decreasing TR. Up to two- to three-fold reductions in TR with 20% TNR gains were achievable. In any given tissue, TNR performance is expected to further improve with heating, due to changes in relaxation rates. CONCLUSION Dual-pathway PSIF-FISP can improve TNR and acquisition speed over standard gradient-recalled echo sequences, but optimal acquisition parameters are tissue dependent. Magn Reson Med 77:1193-1200, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Pelin Aksit Ciris
- Department of Biomedical Engineering, Akdeniz University, Antalya, Turkey.,Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Cheng-Chieh Cheng
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | | | - Lawrence P Panych
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Bruno Madore
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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18
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Cao Z, Oh S, Otazo R, Sica CT, Griswold MA, Collins CM. Complex difference constrained compressed sensing reconstruction for accelerated PRF thermometry with application to MRI-induced RF heating. Magn Reson Med 2015; 73:1420-31. [PMID: 24753099 PMCID: PMC4205230 DOI: 10.1002/mrm.25255] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 01/01/2023]
Abstract
PURPOSE Introduce a novel compressed sensing reconstruction method to accelerate proton resonance frequency shift temperature imaging for MRI-induced radiofrequency heating evaluation. METHODS A compressed sensing approach that exploits sparsity of the complex difference between postheating and baseline images is proposed to accelerate proton resonance frequency temperature mapping. The method exploits the intra-image and inter-image correlations to promote sparsity and remove shared aliasing artifacts. Validations were performed on simulations and retrospectively undersampled data acquired in ex vivo and in vivo studies by comparing performance with previously published techniques. RESULTS The proposed complex difference constrained compressed sensing reconstruction method improved the reconstruction of smooth and local proton resonance frequency temperature change images compared to various available reconstruction methods in a simulation study, a retrospective study with heating of a human forearm in vivo, and a retrospective study with heating of a sample of beef ex vivo. CONCLUSION Complex difference based compressed sensing with utilization of a fully sampled baseline image improves the reconstruction accuracy for accelerated proton resonance frequency thermometry. It can be used to improve the volumetric coverage and temporal resolution in evaluation of radiofrequency heating due to MRI, and may help facilitate and validate temperature-based methods for safety assurance.
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Affiliation(s)
- Zhipeng Cao
- Department of Bioengineering, The Pennsylvania State University, Hershey, Pennsylvania, USA; Department of Radiology, The Pennsylvania State University, Hershey, Pennsylvania, USA
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19
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Boulant N, Bottlaender M, Uhrig L, Giacomini E, Luong M, Amadon A, Massire A, Larrat B, Vignaud A. FID navigator-based MR thermometry method to monitor small temperature changes in the brain of ventilated animals. NMR Biomed 2015; 28:101-107. [PMID: 25388870 DOI: 10.1002/nbm.3232] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 10/07/2014] [Accepted: 10/08/2014] [Indexed: 06/04/2023]
Abstract
An MR thermometry method is proposed for measuring in vivo small temperature changes engendered by external RF heat sources. The method relies on reproducible and stable respiration and therefore currently applies to ventilated animals whose breathing is carefully controlled. It first consists in characterizing the stability of the main magnetic field as well as the variations induced by breathing during a first monitoring stage. Second, RF heating is applied while the phase and thus temperature evolutions are continuously measured, the corrections due to breathing and field drift being made thanks to the data accumulated during the first period. The RF heat source is finally stopped and the temperature rise likewise is continuously monitored during a third and last stage to observe the animal cooling down and to validate the assumptions made for correcting for the main field variation and the physiological noise. Experiments were performed with a clinical 7 T scanner on an anesthetized baboon and with a dedicated RF heating setup. Analysis of the data reveals a precision around 0.1°C, which allows us to reliably measure sub-degree temperature rises in the muscle and in the brain of the animal.
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Affiliation(s)
- Nicolas Boulant
- CEA/DSV/I2BM/NeuroSpin/UNIRS, CEA Saclay, 91191, Gif sur Yvette, France
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20
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Ramsay E, Mougenot C, Köhler M, Bronskill M, Klotz L, Haider MA, Chopra R. MR thermometry in the human prostate gland at 3.0T for transurethral ultrasound therapy. J Magn Reson Imaging 2013; 38:1564-71. [PMID: 23440850 DOI: 10.1002/jmri.24063] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Accepted: 01/10/2013] [Indexed: 11/05/2022] Open
Abstract
PURPOSE To investigate the spatial, temporal, and temperature resolution of a segmented gradient echo echo-planar imaging (EPI) technique as applied to proton resonance frequency (PRF) shift thermometry at 3 T in the human prostate gland, and to determine appropriate sequence parameters for magnetic resonance imaging (MRI)-controlled transurethral ultrasound thermal therapy. MATERIALS AND METHODS Eleven healthy volunteers (age range 23-58) were scanned at 3 T with a 16-channel torso coil to study the behavior of a gradient echo EPI thermometry sequence. The temperature stability and geometric distortion were assessed for 11 different parameter sets. In a further five volunteers, the prostate T2* was measured. RESULTS For all scan parameters investigated, the temperature standard deviation within the prostate was less than 1°C, while the distortion was less than 1 mm. Temperature stability was best with higher TE values (up to 25 msec), larger voxel sizes and lower EPI factors, but this had to be balanced against requirements for good spatial and temporal resolution. Prostate T2* values ranged from 30-50 msec. CONCLUSION A good balance between temperature stability and temporal/spatial resolution is obtained with TE = 15 msec, voxel size = 1.14 mm, and EPI factor = 9, resulting in a dynamic scan time of 7.2 seconds for the nine slices.
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Affiliation(s)
- Elizabeth Ramsay
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
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21
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Taylor BA, Elliott AM, Hwang KP, Hazle JD, Stafford RJ. Correlation between the temperature dependence of intrinsic MR parameters and thermal dose measured by a rapid chemical shift imaging technique. NMR Biomed 2011; 24:1414-1421. [PMID: 21721063 PMCID: PMC3190595 DOI: 10.1002/nbm.1707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 12/23/2010] [Accepted: 02/15/2011] [Indexed: 05/31/2023]
Abstract
In order to investigate simultaneous MR temperature imaging and direct validation of tissue damage during thermal therapy, temperature-dependent signal changes in proton resonance frequency (PRF) shifts, R(2)* values, and T1-weighted amplitudes are measured from one technique in ex vivo tissue. Using a multigradient echo acquisition and the Stieglitz-McBride algorithm, the temperature sensitivity coefficients of these parameters are measured in each tissue at high spatiotemporal resolutions (1.6 x 1.6 x 4 mm 3,≤ 5sec) at the range of 25-61 °C. Non-linear changes in MR parameters are examined and correlated with an Arrhenius rate dose model of thermal damage. Using logistic regression, the probability of changes in these parameters is calculated as a function of thermal dose to determine if changes correspond to thermal damage. Temperature sensitivity of R(2)* and, in some cases, T1-weighted amplitudes are statistically different before and after thermal damage occurred. Significant changes in the slopes of R(2)* as a function of temperature are observed. Logistic regression analysis shows that these changes could be accurately predicted using the Arrhenius rate dose model (Ω = 1.01 ± 0.03), thereby showing that the changes in R(2)* could be direct markers of protein denaturation. Overall, by using a chemical shift imaging technique with simultaneous temperature estimation, R(2)* mapping and T1-W imaging, it is shown that changes in the sensitivity of R(2)* and, to a lesser degree, T1-W amplitudes are measured in ex vivo tissue when thermal damage is expected to occur. These changes could possibly be used for direct validation of thermal damage in contrast to model-based predictions.
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Affiliation(s)
- Brian A. Taylor
- Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
- The University of Texas Graduate School of Biomedical Sciences, Houston, Texas
| | - Andrew M. Elliott
- Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
| | - Ken-Pin Hwang
- Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
- Applied Science Laboratory, GE Healthcare, Waukesha, Wisconsin
| | - John D. Hazle
- Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
| | - R. Jason Stafford
- Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas
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22
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Todd N, Payne A, Parker DL. Model predictive filtering for improved temporal resolution in MRI temperature imaging. Magn Reson Med 2010; 63:1269-79. [PMID: 20432298 PMCID: PMC5450947 DOI: 10.1002/mrm.22321] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 11/11/2009] [Indexed: 11/08/2022]
Abstract
A novel method for reconstructing MRI temperature maps from undersampled data is presented. The method, model predictive filtering, combines temperature predictions from a preidentified thermal model with undersampled k-space data to create temperature maps in near real time. The model predictive filtering algorithm was implemented in three ways: using retrospectively undersampled k-space data from a fully sampled two-dimensional gradient echo (GRE) sequence (reduction factors R = 2.7 to R = 7.1), using actually undersampled data from a two-dimensional GRE sequence (R = 4.8), and using actually undersampled data from a three-dimensional GRE sequence (R = 12.1). Thirty-nine high-intensity focused ultrasound heating experiments were performed under MRI monitoring to test the model predictive filtering technique against the current gold standard for MR temperature mapping, the proton resonance frequency shift method. For both of the two-dimensional implementations, the average error over the five hottest voxels from the hottest time frame remained between +/-0.8 degrees C and the temperature root mean square error over a 24 x 7 x 3 x 25-voxel region of interest remained below 0.35 degrees C. The largest errors for the three-dimensional implementation were slightly worse: -1.4 degrees C for the mean error of the five hottest voxels and 0.61 degrees C for the temperature root mean square error.
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Affiliation(s)
- Nick Todd
- Department of Physics, University of Utah, Salt Lake City, Utah, USA.
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Abstract
PURPOSE A review of MRI temperature imaging methods based on intermolecular multiple quantum coherences (iMQCs) is presented. Temperature imaging based on iMQCs can provide absolute temperature maps that circumvent the artefacts that other proton frequency shift techniques suffer from such as distortions to the detected temperature due to susceptibility changes and magnetic field inhomogeneities. Thermometry based on iMQCs is promising in high-fat tissues such as the breast, since it relies on the fat signal as an internal reference. This review covers the theoretical background of iMQCs, and the necessary adaptations for temperature imaging using iMQCs. MATERIALS AND METHODS Data is presented from several papers on iMQC temperature imaging. These studies were done at 7T in both phantoms and in vivo. Results from phantoms of cream (homogeneous mixture of water and fat) are presented as well as in vivo temperature maps in obese mice. RESULTS Thermometry based on iMQCs offers the potential to provide temperature maps which are free of artefacts due to susceptibility and magnetic field inhomogeneities, and detect temperature on an absolute scale. CONCLUSIONS The data presented in the papers reviewed highlights the promise of iMQC-based temperature imaging in fatty tissues such as the breast. The change in susceptibility of fat with temperature makes standard proton frequency shift methods (even with fat suppression) challenging and iMQC-based imaging offers an alternative approach.
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