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Ozenne V, Bour P, Denis de Senneville B, Quesson B. 3D motion strategy for online volumetric thermometry using simultaneous multi-slice EPI at 1.5T: an evaluation study. Int J Hyperthermia 2023; 40:2194595. [PMID: 37080550 DOI: 10.1080/02656736.2023.2194595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023] Open
Abstract
PURPOSE In presence of respiratory motion, temperature mapping is altered by in-plane and through-plane displacements between successive acquisitions together with periodic phase variations. Fast 2D Echo Planar Imaging (EPI) sequence can accommodate intra-scan motion, but limited volume coverage and inter-scan motion remain a challenge during free-breathing acquisition since position offsets can arise between the different slices. METHOD To address this limitation, we evaluated a 2D simultaneous multi-slice EPI sequence with multiband (MB) acceleration during radiofrequency ablation on a mobile gel and in the liver of a volunteer (no heating). The sequence was evaluated in terms of resulting inter-scan motion, temperature uncertainty and elevation, potential false-positive heating and repeatability. Lastly, to account for potential through-plane motion, a 3D motion compensation pipeline was implemented and evaluated. RESULTS In-plane motion was compensated whatever the MB factor and temperature distribution was found in agreement during both the heating and cooling periods. No obvious false-positive temperature was observed under the conditions being investigated. Repeatability of measurements results in a 95% uncertainty below 2 °C for MB1 and MB2. Uncertainty up to 4.5 °C was reported with MB3 together with the presence of aliasing artifacts. Lastly, fast simultaneous multi-slice EPI combined with 3D motion compensation reduce residual out-of-plane motion. CONCLUSION Volumetric temperature imaging (12 slices/700 ms) could be performed with 2 °C accuracy or less, and offer tradeoffs in acquisition time or volume coverage. Such a strategy is expected to increase procedure safety by monitoring large volumes more rapidly for MR-guided thermotherapy on mobile organs.
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Affiliation(s)
- Valéry Ozenne
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France
- University of 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, Pessac-Bordeaux, France
- University of Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
- INSERM, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
| | | | - Bruno Quesson
- IHU Liryc, Electrophysiology and Heart Modeling Institute, Fondation Bordeaux Université, Pessac-Bordeaux, France
- University of 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
The unique ability of magnetic resonance imaging to measure temperature noninvasively, in vivo, makes it an attractive tool for monitoring interventional procedures, such as radiofrequency or microwave ablation in real-time. The most frequently used approach for magnetic resonance-based temperature measurement is proton resonance frequency (PRF) thermometry. Although it has many advantages, including tissue-independence and real-time capability, the main drawback is its motion sensitivity. This is likely the reason PRF thermometry in moving organs, such as the liver, is not commonly used in the clinical arena. In recent years, however, several developments suggest that motion-corrected thermometry in the liver is achievable. The present article summarizes the diverse attempts to correct thermometry in the liver. Therefore, the physical principle of PRF is introduced, with additional references for necrosis zone estimation and how to deal with fat phase modulation, and main magnetic field drifts. The primary categories of motion correction are presented, including general methods for motion compensation and library-based approaches, and referenceless thermometry and hybrid methods. Practical validation of the described methods in larger patient groups will be necessary to establish accurate motion-corrected thermometry in the clinical arena, with the goal of complete liver tumor ablation.
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Abstract
Focused ultrasound (FUS/HIFU) relies on ablation of pathological tissues by delivering a sufficiently high level of acoustic energy in situ of the human body. Magnetic Resonance guided FUS (MRgFUS/HIFU) and Ultrasound guided (USgFUS/HIFU) are image guided techniques combined with therapeutic FUS for monitoring purposes. The principles and technologies of FUS/HiFU are described in this paper including the basics of MR guidance techniques and MR temperature mapping. Clinical applications of FUS/HIFU gained CE and FDA approvals for the treatment of various benign and few malignant lesions in the last two decades. Current technical limitations of ultrasound guided and MRI guided Focused Ultrasound, as well as adverse effects for the application of this technique are outlined including challenges of ablating moving organs (liver and kidney). An outlook to possible applications is provided; exampling clinical trials discussing future options.
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Affiliation(s)
- Senay Mihcin
- a Institute for Medical Science and Technology , Universities Dundee & St. Andrews Ninewells Hospital and Medical School , Dundee , UK
| | - Andreas Melzer
- b Division Medical Technology, Institute for Medical Science and Technology , Universities Dundee & St. Andrews Ninewells Hospital and Medical School , Dundee , UK
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Petrusca L, Salomir R, Manasseh G, Becker CD, Terraz S. Spatio-temporal quantitative thermography of pre-focal interactions between high intensity focused ultrasound and the rib cage. Int J Hyperthermia 2015; 31:421-32. [PMID: 25753370 DOI: 10.3109/02656736.2015.1009501] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE The aim of this paper is to quantitatively investigate the thermal effects generated by the pre-focal interactions of a HIFU beam with a rib cage, in the context of minimally invasive transcostal therapy of liver malignancies. MATERIALS AND METHODS HIFU sonications were produced by a phased-array MR-compatible transducer on Turkey muscle placed on a sheep thoracic cage specimen. The thoracic wall was positioned in the pre-focal zone 3.5 to 6.5 cm below the focus. Thermal monitoring was simultaneously performed using fluoroptic sensors inserted into the medullar cavity of the ribs and high resolution MR-thermometry (voxel: 1 × 1 × 5 mm3, four multi-planar slices). RESULTS MR-thermometry data indicated nearly isotropic distribution of the thermal energy at the ribs' surface. The temperature elevation at the focus was comparable with the pericostal temperature elevation around unprotected ribs, while being systematically inferior, by more than a factor of four on average, to the intra-medullar values. The spatial profiles of the pericostal and intra-medullar thermal build-up measurements could be smoothly connected using a Gaussian function. The dynamics of the post-sonication thermal relaxation as determined by fluoroptic measurements was demonstrated to be theoretically coherent with the experimental observations. CONCLUSION The experimental findings motivate further efforts for the transfer towards clinical routine of effective rib-sparing strategies for hepatic HIFU.
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Affiliation(s)
- Lorena Petrusca
- Hepatobiliary Interventional Radiology, Faculty of Medicine, University of Geneva , Geneva, Switzerland
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Kwon OI, Chauhan M, Kim HJ, Jeong WC, Wi H, Oh TI, Woo EJ. Fast conductivity imaging in magnetic resonance electrical impedance tomography (MREIT) for RF ablation monitoring. Int J Hyperthermia 2014; 30:447-55. [PMID: 25329351 DOI: 10.3109/02656736.2014.966337] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
PURPOSE This study shows the potential of magnetic resonance electrical impedance tomography (MREIT) as a non-invasive RF ablation monitoring technique. MATERIALS AND METHODS We prepared bovine muscle tissue with a pair of needle electrodes for RF ablation, a temperature sensor, and two pairs of surface electrodes for conductivity image reconstructions. We used the injected current non-linear encoding with multi-echo gradient recalled echo (ICNE-MGRE) pulse sequence in a series of MREIT scans for conductivity imaging. We acquired magnetic flux density data induced by externally injected currents, while suppressing other phase artefacts. We used an 8-channel RF head coil and 8 echoes to improve the signal-to-noise ratio (SNR) in measured magnetic flux density data. Using the measured data, we reconstructed a time series of 180 conductivity images at every 10.24 s during and after RF ablation. RESULTS Tissue conductivity values in the lesion increased with temperature during RF ablation. After reaching 60 °C, a steep increase in tissue conductivity values occurred with relatively little temperature increase. After RF ablation, tissue conductivity values in the lesion decreased with temperature, but to values different from those before ablation due to permanent structural changes of tissue by RF ablation. CONCLUSION We could monitor temperature and also structural changes in tissue during RF ablation by producing spatio-temporal maps of tissue conductivity values using a fast MREIT conductivity imaging method. We expect that the new monitoring method could be used to estimate lesions during RF ablation and improve the efficacy of the treatment.
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Affiliation(s)
- Oh In Kwon
- Department of Mathematics, Konkuk University , Seoul , Korea and
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Woo Chul Jeong, Sajib S, Hyung Joong Kim, Oh In Kwon. Focused Current Density Imaging Using Internal Electrode in Magnetic Resonance Electrical Impedance Tomography (MREIT). IEEE Trans Biomed Eng 2014; 61:1938-46. [DOI: 10.1109/tbme.2014.2306913] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Petrusca L, Auboiroux V, Goget T, Viallon M, Muller A, Gross P, Becker CD, Salomir R. A nonparametric temperature controller with nonlinear negative reaction for multi-point rapid MR-guided HIFU ablation. IEEE TRANSACTIONS ON MEDICAL IMAGING 2014; 33:1324-1337. [PMID: 24893259 DOI: 10.1109/tmi.2014.2310704] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Magnetic resonance-guided high intensity focused ultrasound (MRgHIFU) is a noninvasive method for thermal ablation, which exploits the capabilities of magnetic resonance imaging (MRI) for excellent visualization of the target and for near real-time thermometry. Oncological quality of ablation may be obtained by volumetric sonication under automatic feedback control of the temperature. For this purpose, a new nonparametric (i.e., model independent) temperature controller, using nonlinear negative reaction, was designed and evaluated for the iterated sonication of a prescribed pattern of foci. The main objective was to achieve the same thermal history at each sonication point during volumetric MRgHIFU. Differently sized linear and circular trajectories were investigated ex vivo and in vivo using a phased-array HIFU transducer. A clinical 3T MRI scanner was used and the temperature elevation was measured in five slices simultaneously with a voxel size of 1 ×1 ×5 mm(3) and temporal resolution of 4 s. In vivo results indicated a similar thermal history of each sonicated focus along the prescribed pattern, that was 17.3 ± 0.5 °C as compared to 16 °C prescribed temperature elevation. The spatio-temporal control of the temperature also enabled meaningful comparison of various sonication patterns in terms of dosimetry and near-field safety. The thermal build-up tended to drift downwards in the HIFU transducer with a circular scan.
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Petrusca L, Viallon M, Breguet R, Terraz S, Manasseh G, Auboiroux V, Goget T, Baboi L, Gross P, Sekins KM, Becker CD, Salomir R. An experimental model to investigate the targeting accuracy of MR-guided focused ultrasound ablation in liver. J Transl Med 2014; 12:12. [PMID: 24433332 PMCID: PMC3901025 DOI: 10.1186/1479-5876-12-12] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 01/03/2014] [Indexed: 11/10/2022] Open
Abstract
Background Magnetic Resonance-guided High Intensity Focused Ultrasound (MRgHIFU) is a hybrid technology that aims to offer non-invasive thermal ablation of targeted tumors or other pathological tissues. Acoustic aberrations and non-linear wave propagating effects may shift the focal point significantly away from the prescribed (or, theoretical) position. It is therefore mandatory to evaluate the spatial accuracy of ablation for a given HIFU protocol and/or device. We describe here a method for producing a user-defined ballistic target as an absolute reference marker for MRgHIFU ablations. Methods The investigated method is based on trapping a mixture of MR contrast agent and histology stain using radiofrequency (RF) ablation causing cell death and coagulation. A dedicated RF-electrode was used for the marker fixation as follows: a RF coagulation (4 W, 15 seconds) and injection of the mixture followed by a second RF coagulation. As a result, the contrast agent/stain is encapsulated in the intercellular space. Ultrasonography imaging was performed during the procedure, while high resolution T1w 3D VIBE MR acquisition was used right after to identify the position of the ballistic marker and hence the target tissue. For some cases, after the marker fixation procedure, HIFU volumetric ablations were produced by a phased-array HIFU platform. First ex vivo experiments were followed by in vivo investigation on four rabbits in thigh muscle and six pigs in liver, with follow-up at Day 7. Results At the end of the procedure, no ultrasound indication of the marker’s presence could be observed, while it was clearly visible under MR and could be conveniently used to prescribe the HIFU ablation, centered on the so-created target. The marker was identified at Day 7 after treatment, immediately after animal sacrifice, after 3 weeks of post-mortem formalin fixation and during histology analysis. Its size ranged between 2.5 and 4 mm. Conclusions Experimental validation of this new ballistic marker method was performed for liver MRgHIFU ablation, free of any side effects (e.g. no edema around the marker, no infection, no bleeding). The study suggests that the absolute reference marker had ultrasound conspicuity below the detection threshold, was irreversible, MR-compatible and MR-detectable, while also being a well-established histology staining technique.
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Affiliation(s)
- Lorena Petrusca
- Faculty of Medicine, University of Geneva, Geneva, Switzerland.
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Viallon M, Petrusca L, Auboiroux V, Goget T, Baboi L, Becker CD, Salomir R. Experimental methods for improved spatial control of thermal lesions in magnetic resonance-guided focused ultrasound ablation. ULTRASOUND IN MEDICINE & BIOLOGY 2013; 39:1580-1595. [PMID: 23820250 DOI: 10.1016/j.ultrasmedbio.2013.03.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 03/10/2013] [Accepted: 03/13/2013] [Indexed: 06/02/2023]
Abstract
Magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU, or MRgFUS) is a hybrid technology that was developed to provide efficient and tolerable thermal ablation of targeted tumors or other pathologic tissues, while preserving the normal surrounding structures. Fast 3-D ablation strategies are feasible with the newly available phased-array HIFU transducers. However, unlike fixed heating sources for interstitial ablation (radiofrequency electrode, microwave applicator, infra-red laser applicator), HIFU uses propagating waves. Therefore, the main challenge is to avoid thermo-acoustical adverse effects, such as energy deposition at reflecting interfaces and thermal drift of the focal lesion toward the near field. We report here our investigations on some novel experimental solutions to solve, or at least to alleviate, these generally known tolerability problems in HIFU-based therapy. Online multiplanar MR thermometry was the main investigational tool extensively used in this study to identify the problems and to assess the efficacy of the tested solutions. We present an improved method to cancel the beam reflection at the exit window (i.e., tissue-to-air interface) by creating a multilayer protection, to dissipate the residual HIFU beam by bulk scattering. This study evaluates selective de-activation of transducer elements to reduce the collateral heating at bone surfaces in the far field, mainly during automatically controlled volumetric ablation. We also explore, using hybrid US/MR simultaneous imaging, the feasibility of using disruptive boiling at the focus, both as a far-field self-shielding technique and as an enhanced ablation strategy (i.e., boiling core controlled HIFU ablation).
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Affiliation(s)
- Magalie Viallon
- Department of Radiology, University Hospitals of Geneva, Geneva, Switzerland.
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Magnetic Resonance–Guided Shielding of Prefocal Acoustic Obstacles in Focused Ultrasound Therapy. Invest Radiol 2013; 48:366-80. [DOI: 10.1097/rli.0b013e31827a90d7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Oh TI, Kim HJ, Jeong WC, Chauhan M, Kwon OI, Woo EJ. Detection of temperature distribution via recovering electrical conductivity in MREIT. Phys Med Biol 2013; 58:2697-711. [DOI: 10.1088/0031-9155/58/8/2697] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kickhefel A, Rosenberg C, Roland J, Viallon M, Gross P, Schick F, Hosten N, Salomir R. A pilot study for clinical feasibility of the near-harmonic 2D referenceless PRFS thermometry in liver under free breathing using MR-guided LITT ablation data. Int J Hyperthermia 2012; 28:250-66. [PMID: 22515346 DOI: 10.3109/02656736.2012.670834] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVES The conventional implementations of proton resonance frequency shift (PRFS) magnetic resonance thermometry (MRT) require the subtraction of single or multiple temporal references, a motion sensitive critical feature. A pilot study was conducted here to investigate the clinical feasibility of near-harmonic two-dimensional (2D) referenceless PRFS MRT, using patient data from MR-guided laser ablation of liver malignancies. METHODS PRFS MRT with respiratory-triggered multi-slice gradient-recalled (GRE) acquisition was performed under free breathing in six patients. The precision of the novel referenceless MRT was compared with the reference phase subtraction. Coupling the referenceless MRT with a model-based, real-time compatible regularisation algorithm was also investigated. RESULTS The precision of MRT was improved by a factor of 3.3 when using the referenceless method as compared to the reference phase subtraction. The approach combining referenceless PRFS MRT and model-based regularisation yielded an estimated precision of 0.7° to 2.1°C, resulting in millimetre-range agreement between the calculated thermal dose and the 24 h post-treatment unperfused regions in liver. CONCLUSIONS The application of the near-harmonic 2D referenceless MRT method was feasible in a clinical scenario of MR-guided laser-induced thermal therapy (LITT) ablation in liver and permitted accurate prediction of the thermal lesion under free breathing in conscious patients, obviating the need for a controlled breathing under general anaesthesia.
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Affiliation(s)
- Antje Kickhefel
- Diagnostic and Interventional Radiology, Eberhard Karls University, Tübingen, Germany.
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Auboiroux V, Petrusca L, Viallon M, Goget T, Becker CD, Salomir R. Ultrasonography-based 2D motion-compensated HIFU sonication integrated with reference-free MR temperature monitoring: a feasibility studyex vivo. Phys Med Biol 2012; 57:N159-71. [DOI: 10.1088/0031-9155/57/10/n159] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Vogl TJ, Huebner F, Naguib NNN, Bauer RW, Mack MG, Nour-Eldin NEA, Meister D. MR-based thermometry of laser induced thermotherapy: temperature accuracy and temporal resolution in vitro at 0.2 and 1.5 T magnetic field strengths. Lasers Surg Med 2012; 44:257-65. [PMID: 22407543 DOI: 10.1002/lsm.22012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2012] [Indexed: 01/12/2023]
Abstract
PURPOSE To evaluate MR-thermometry using fast MR sequences for laser induced interstitial thermotherapy (LITT) at 0.2 and 1.5 T systems. METHODS & MATERIALS In-vitro experiments were performed using Agarose gel mixture and lobes of porcine liver. MR-thermometry was performed by means of longitudinal relaxation time (T1) and proton resonance frequency shift (PRF) methods under acquisition of amplitude and phase shift images. Four different sequences were used for T1 thermometry: A gradient-echo (GRE), a True Fast Imaging with Steady Precession (TRUFI), a Saturation Recovery Turbo-FLASH (SRTF), and an Inversion Recovery Turbo-FLASH (IRTF) sequence (FLASH-Fast Low Angle Shot). PRF was measured with four sequences: Two fast-spoiled GRE sequences (one as WIP sequence), a Turbo-FLASH (TFL) sequence (WIP sequence), and a multiecho-TrueFISP sequence. Temperature was controlled and verified using a fiber-optic Luxtron device. The temperature was correlated with the MR measurement. RESULTS All sequences showed a good linear correlation R(2) = 0.97-0.99 between the measured temperature and the MR-thermometry measurements. The only exception was the TRUFI sequence in the Agarose phantom that showed a non-linear calibration curve R(2) = 0.39-0.67. At 1.5 T, the Agarose experiments revealed similar temperature accuracies of 4-6°C for all sequences excluding TRUFI. During experiments with the liver, the PRF sequences showed better performance than the T1, with accuracies of 5-12°C, contrary to the T1 sequences at 14-18°C. The accuracy of the Siemens PRF-FLASH sequence was 5.1°C. At 0.2 T, the Agarose experiments provided the highest accuracy of 3.3°C for PRF measurement. At the liver experiments the T1 sequences SRTF and FLASH revealed the best accuracies at 6.4 and 7.0°C. CONCLUSION The accuracy and speed of MR temperature measurements are sufficient for controlling the temperature-based tumor destruction. For 0.2 T systems SRTF and FLASH sequences are recommended. For 1.5 T systems SRTF and FLASH are the most accurate.
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Affiliation(s)
- Thomas J Vogl
- Institute for Diagnostic and Interventional Radiology, Johann Wolfgang Goethe University Hospital, Frankfurt University, Frankfurt, Germany.
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Auboiroux V, Viallon M, Roland J, Hyacinthe JN, Petrusca L, Morel DR, Goget T, Terraz S, Gross P, Becker CD, Salomir R. ARFI-prepared MRgHIFU in liver: simultaneous mapping of ARFI-displacement and temperature elevation, using a fast GRE-EPI sequence. Magn Reson Med 2012; 68:932-46. [PMID: 22246646 DOI: 10.1002/mrm.23309] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 10/25/2011] [Accepted: 11/07/2011] [Indexed: 01/18/2023]
Abstract
MR acoustic radiation force imaging (ARFI) is an elegant adjunct to MR-guided high intensity focused ultrasound for treatment planning and optimization, permitting in situ assessment of the focusing and targeting quality. The thermal effect of high intensity focused ultrasound pulses associated with ARFI measurements is recommended to be monitored on line, in particular when the beam crosses highly absorbent structures or interfaces (e.g., bones or air-filled cavities). A dedicated MR sequence is proposed here, derived from a segmented gradient echo-echo planar imaging kernel by adding a bipolar motion encoding gradient with interleaved alternating polarities. Temporal resolution was reduced to 2.1 s, with in-plane spatial resolution of 1 mm. MR-ARFI measurements were executed during controlled animal breathing, with trans-costal successively steered foci, to investigate the spatial modulation of the focus intensity and the targeting offset. ARFI-induced tissue displacement measurements enabled the accurate localization, in vivo, of the high intensity focused ultrasound focal point in sheep liver, with simultaneous monitoring of the temperature elevation. ARFI-based precalibration of the focal point position was immediately followed by trans-costal MR-guided high intensity focused ultrasound ablation, monitored with a conventional proton resonance frequency shift MR thermometry sequence. The latter MR thermometry sequence had spatial resolution and geometrical distortion identical with the ARFI maps, hence no coregistration was required.
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Kickhefel A, Rosenberg C, Weiss CR, Rempp H, Roland J, Schick F, Hosten N. Clinical evaluation of MR temperature monitoring of laser-induced thermotherapy in human liver using the proton-resonance-frequency method and predictive models of cell death. J Magn Reson Imaging 2011; 33:704-12. [PMID: 21563256 DOI: 10.1002/jmri.22499] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
PURPOSE To assess the feasibility, precision, and accuracy of real-time temperature mapping (TMap) during laser-induced thermotherapy (LITT) for clinical practice in patients liver with a gradient echo (GRE) sequence using the proton resonance frequency (PRF) method. MATERIALS AND METHODS LITT was performed on 34 lesions in 18 patients with simultaneous real-time visualization of relative temperature changes. Correlative contrast-enhanced T1-weighted magnetic resonance (MR) images of the liver were acquired after treatment using the same slice positions and angulations as TMap images acquired during LITT. For each slice, TMap and follow-up images were registered for comparison. Afterwards, segmentation based on temperature (T) >52°C on TMap and based on necrosis seen on follow-up images was performed. These segmented structures were overlaid and divided into zones where the TMap was found to either over- or underestimate necrosis on the postcontrast images. Regions with T>52°C after 20 minutes were defined as necrotic tissue based on data received from two different thermal dose models. RESULTS The average intersecting region of TMap and necrotic zone was 87% ± 5%, the overestimated 13% ± 4%, and the underestimated 13% ± 5%. CONCLUSION This study demonstrates that MR temperature mapping appears reasonably capable of predicting tissue necrosis on the basis of indicating regions having greater temperatures than 52°C and could be used to monitor and adjust the thermal therapy appropriately during treatment.
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Wyatt CR, Soher BJ, MacFall JR. Correction of breathing-induced errors in magnetic resonance thermometry of hyperthermia using multiecho field fitting techniques. Med Phys 2011; 37:6300-9. [PMID: 21302786 DOI: 10.1118/1.3515462] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
PURPOSE Breathing motion can create large errors when performing magnetic resonance (MR) thermometry of the breast. Breath holds can be used to minimize these errors, but not eliminate them. Between breath holds, the referenceless method can be used to further reduce errors by relying on regions of nonheated fatty tissue surrounding the heated region. When the surrounding tissue is heated (i.e., for a hyperthermia treatment), errors can result due to phase changes of the small amounts of water in the tissue. Therefore, an extension of the referenceless method is proposed which fits for the field in fatty tissue independent of temperature change and extrapolates it to the water-rich regions. METHODS Nonheating experiments were performed with male volunteers performing breath holds on top of a phantom mimicking a breast with a tumor. Heating experiments were also conducted with the same phantom while mechanically simulated breath holds were performed. A nonheating experiment was also performed with a healthy female breast. For each experiment, a nonlinear fitting algorithm was used to fit for temperature change and B0 field inside of the fatty tissue. The field changes were then extrapolated into water-rich (tumor) portions of the image using a least-squares fit to a fifth-order equation, to correct for field changes due to breath hold changes. Similar results were calculated using the image phase, to mimic the use of the referenceless method. RESULTS Phantom results showed large reduction of mean error and standard deviation. In the non-heating experiments, the traditional referenceless method and our extended method both corrected by similar amounts. However, in the heating experiments, the average deviation of the temperature calculated with the extended method from a fiber optic probe temperature was approximately 50% less than the deviation with the referenceless method. The in vivo breast results demonstrated reduced standard deviation and mean. CONCLUSIONS In this paper, we have developed an extension of the referenceless method to correct for breathing errors using multiecho fitting methods to fit for the B0 field in the fatty tissue and using measured field changes as references to extrapolate field corrections into a water-only (tumor) region. This technique has been validated in a number of situations, and in all cases, the correction method has been shown to greatly reduce temperature error in water-rich regions. The method has also been shown to be an improvement over similar methods that use image phase changes instead of field changes, particularly when temperature changes are induced.
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Affiliation(s)
- Cory R Wyatt
- Department of Radiology, Duke University Medical Center, Duke University, P.O. Box 3808, Durham, North Carolina 27710, USA.
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Quesson B, Laurent C, Maclair G, de Senneville BD, Mougenot C, Ries M, Carteret T, Rullier A, Moonen CTW. Real-time volumetric MRI thermometry of focused ultrasound ablation in vivo: a feasibility study in pig liver and kidney. NMR IN BIOMEDICINE 2011; 24:145-153. [PMID: 21344531 DOI: 10.1002/nbm.1563] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2009] [Revised: 04/13/2010] [Accepted: 04/14/2010] [Indexed: 05/28/2023]
Abstract
MR thermometry offers the possibility to precisely guide high-intensity focused ultrasound (HIFU) for the noninvasive treatment of kidney and liver tumours. The objectives of this study were to demonstrate therapy guidance by motion-compensated, rapid and volumetric MR temperature monitoring and to evaluate the feasibility of MR-guided HIFU ablation in these organs. Fourteen HIFU sonications were performed in the kidney and liver of five pigs under general anaesthesia using an MR-compatible Philips HIFU platform prototype. HIFU sonication power and duration were varied. Volumetric MR thermometry was performed continuously at 1.5 T using the proton resonance frequency shift method employing a multi-slice, single-shot, echo-planar imaging sequence with an update frequency of 2.5 Hz. Motion-related suceptibility artefacts were compensated for using multi-baseline reference images acquired prior to sonication. At the end of the experiment, the animals were sacrificed for macroscopic and microscopic examinations of the kidney, liver and skin. The standard deviation of the temperature measured prior to heating in the sonicated area was approximately 1 °C in kidney and liver, and 2.5 °C near the skin. The maximum temperature rise was 30 °C for a sonication of 1.2 MHz in the liver over 15 s at 300 W. The thermal dose reached the lethal threshold (240 CEM(43) ) in two of six cases in the kidney and four of eight cases in the liver, but remained below this value in skin regions in the beam path. These findings were in agreement with histological analysis. Volumetric thermometry allows real-time monitoring of the temperature at the target location in liver and kidney, as well as in surrounding tissues. Thermal ablation was more difficult to achieve in renal than in hepatic tissue even using higher acoustic energy, probably because of a more efficient heat evacuation in the kidney by perfusion.
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Affiliation(s)
- Bruno Quesson
- Laboratoire d'Imagerie Moleculaire et Fonctionnelle, UMR 5231 CNRS/Université Victor Segalen Bordeaux 2, Bordeaux, France.
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Rempp H, Clasen S, Boss A, Roland J, Kickhefel A, Schraml C, Claussen CD, Schick F, Pereira PL. Prediction of cell necrosis with sequential temperature mapping after radiofrequency ablation. J Magn Reson Imaging 2009; 30:631-9. [DOI: 10.1002/jmri.21863] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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